tag:blogger.com,1999:blog-97972392024-03-08T10:41:11.914+08:00tHE tiDE cHAsERFollow the photographic trail of a nature enthusiast as he explores the various marine and terrestrial ecosystems of Singapore and the region, and find out more about our little known flora and fauna.Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.comBlogger600125tag:blogger.com,1999:blog-9797239.post-76355096238801702142013-07-28T13:09:00.000+08:002013-08-06T23:25:31.440+08:00Classification of Animals (Kingdom Animalia) for Beginners<div dir="ltr" style="text-align: left;" trbidi="on">
Animals (kingdom Animalia) are multicellular organisms that get the energy they need by consuming food. They are eukaryotes, i.e living things with cells containing a nucleus and other structures enclosed within membranes. They, however, lack rigid cell walls. All animals are able to move at least some part of their body, and many are able to move from place to place.<br />
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The various species of animals can be scientifically classified into smaller groups (called phyla) based on their physical appearances and, more recently, their DNA as well. A wide variety of animals from various phyla have been recorded from Singapore, and the members of the same phyla usually share a few physical or behavioural adaptations.<br />
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Here are some of the distinguishing features that will be useful in helping to make an educated guess of the phylum of an unfamiliar animal encountered in Singapore.<br />
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<b>1. <a href="http://tidechaser.blogspot.sg/2013/03/sponges-porifera-singapore.html">Sponges (Phylum Porifera)</a></b><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXZSs4It2u73lkwFNQt_SaZA4DjC4y2GNHPgYjecBXCVCK-W2G-ecOUtj0YKCmBLFL9oCndSaNZ8Qpw99-qMtLpd0to9YrXx0mVDRbcU2IexrJ6SHFnpYiEgjD__MvF97IWnU-/s1600/porifera.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXZSs4It2u73lkwFNQt_SaZA4DjC4y2GNHPgYjecBXCVCK-W2G-ecOUtj0YKCmBLFL9oCndSaNZ8Qpw99-qMtLpd0to9YrXx0mVDRbcU2IexrJ6SHFnpYiEgjD__MvF97IWnU-/s400/porifera.jpg" width="400" /></a>
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<b>Field characteristics:</b><br />
<ul style="text-align: left;">
<li>Usually have many small pores and one or more bigger openings.</li>
<li>Cells display considerable degree of independence.</li>
<li>Sessile and little detectable movement.</li>
<li>The body has no obvious symmetry.</li>
</ul>
<b>May be confused with:</b><br />
<ul style="text-align: left;">
<li><a href="http://tidechaser.blogspot.sg/2012/12/hard-corals-scleractinia-singapore.html">Hard corals</a> - Some of the colourful sponges are often mistaken to be hard corals. Hard corals, however, have hard, rock-like skeletons, while sponges have a spongy or rubbery feel when touch. Avoid touching sponges with your bare hands though (wear gloves!), as many species have sharp spicules.</li>
<li><a href="http://tidechaser.blogspot.sg/2012/12/soft-corals-alcyonacea-singapore.html">Soft corals</a> - Some sponges with leaf-like or tree-like growth forms may be mistaken for soft corals. Sponges tend to be covered in tiny pores of varying sizes, but not soft corals.</li>
<li><a href="http://tidechaser.blogspot.sg/2013/01/moss-animals-bryozoa-singapore.html">Bryozoans</a> - Encrusting or lace-like bryozoans may be mistaken for sponges. A closer examination will reveal <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg2p6NPaAlDSyUzF3MNb8yOT8oe-G10PmsbWj0VWdobiDQV5V70eIvAL9nfQ-x4x6Vbf5Jar5FktDQFKuAKGipFFB8pe3vHTRoNbcPUbnHXcxZS0yjpRxA_SOOwdugp5C1Qoay4/s1600/Bryozoan-4.jpg">cell-like patterns</a> in the bryozoans, which are the zooecia (or exoskeleton) of the individual zooids (the bryozoan animal).</li>
<li><a href="http://tidechaser.blogspot.sg/2013/05/tunicates-ascidians-salps-singapore.html">Tunicates</a> - Colonial tunicates are often mistaken for sponges. To differentiate them from the latter, take a closer look to spot the <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJJhbszv3Ag5Uwj8nPktCLevKxFbSFXZJ-uvlnymq_D6ruErclN0zxpBWoCqXn6WqLhM2ANImF_CTT7d-ty6GNwxWuuUsPhbKjMp5tN5Ie8BlCx2XKUyxrAEQj7e7Kk8eKBMrB/s1600/zooids.jpg">individual zooids</a> that will not be present in sponges.</li>
<li><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj1zGbISgrmCo00db27YAetwvQH80mj8QU07EcmxOTE3E8cLpOl7rYQ0QvimsAXCULRQp2jxxQsuJJ1CYSMfqPGYW0zL7DSuplglR6Wt3tUryw_RTIjLdnmt0RS2A9zHN7VhY8Dkg/s1600/seaweed.jpg">Seaweed</a> - Some <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgWm82Oc7AWKrRXLSlMrycZdEssJZF5MUulBs7EA9k_NZdee8BhvmVZ2JmJ5EuPPDwbhyphenhyphenk2UP1aoJTkK3qRvChXDXzZc9NrR7q9EI6rcA3VI6ezRjKOWPN8QZPx43JjH6fXJzA3/s1600/Halichondria-cartilaginea.JPG">sponges harbour symbiotic algae</a> in them and appear plant-like. </li>
</ul>
<div style="text-align: right;">
<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/03/sponges-porifera-singapore.html"><b>>> more</b></a></span></div>
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<b>2. <a href="http://tidechaser.blogspot.com/2013/02/comb-jellies-ctenophora-singapore.html">Comb Jellies (Phylum Ctenophora)</a></b><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQJ40jI7tP_x8hff61pWU6xT4W8-UVWLJBd0oSzz2p95diqB4cc8Vv79IVjwNKqmrXWIU9qwxntg_u7wS_gYHRkzUgmwFxkdjAYJVBAIgNgQnE_tj3CIhb9_EN0PTxt_u0IjIp/s1600/Comb-Jelly.jpg"><img alt="Comb jelly (phylum Ctenophora)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQJ40jI7tP_x8hff61pWU6xT4W8-UVWLJBd0oSzz2p95diqB4cc8Vv79IVjwNKqmrXWIU9qwxntg_u7wS_gYHRkzUgmwFxkdjAYJVBAIgNgQnE_tj3CIhb9_EN0PTxt_u0IjIp/s400/Comb-Jelly.jpg" title="Comb jelly (phylum Ctenophora)" width="400" /></a><br />
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<b>Field characteristics:</b><br />
<ul style="text-align: left;">
<li>Jellyfish-like (free-swimming ones) or flatworm-like (non-swimming ones).</li>
<li>Many of free-swimming and non-swimming ones come with a pair of long tentacles fringed with smaller tentacles. See <a href="http://upload.wikimedia.org/wikipedia/commons/thumb/e/ec/Coeloplana_astericola_%28Benthic_ctenophores%29_on_Echniaster_luzonicus_%28Seastar%29.jpg/800px-Coeloplana_astericola_%28Benthic_ctenophores%29_on_Echniaster_luzonicus_%28Seastar%29.jpg" target="_blank">this photo from Wikimedia</a> which features numerous flatworm-like ctenophores extending their long tentacles on a sea star.</li>
<li>Most free-swimming species have eight strips (called comb rows) running down the length of their body. Each strip bears bands of hair-like projections (or cilia) which resemble a comb.</li>
</ul>
<b>May be confused with:</b><br />
<ul style="text-align: left;">
<li><a href="http://tidechaser.blogspot.sg/2013/01/jellyfish-scyphozoa-singapore.html">Scyphozoan jellyfish</a> - Scyphozoan jellyfish generally have numerous (instead of only two) tentacles, and lack the comb rows.</li>
<li><a href="http://tidechaser.blogspot.sg/2013/01/hydroids-hydrozoa-singapore.html#hydromedusae">Hydromedusae</a> - Mature hydrozoans sometimes exist as a free-swimming medusa (jellyfish). They generally have numerous (instead of only two) tentacles, and lack the comb rows.</li>
<li><a href="http://tidechaser.blogspot.sg/2012/08/flatworms-platyhelminthes-singapore.html">Flatworms</a> - Non-swimming ctenophores often somewhat resemble flatworms, but they possess the long tentacles fringed with smaller tentacles which the latter lack.</li>
</ul>
<div style="text-align: right;">
<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.com/2013/02/comb-jellies-ctenophora-singapore.html"><b>>> more</b></a></span></div>
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<b>3. <a href="http://tidechaser.blogspot.sg/2013/01/cnidarians-cnidaria-singapore.html">Cnidarians (Phylum Cnidaria)</a></b><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglFzPoa00uTDV7IpehNE_SonQ_IqomWJMrAyGfsMqvmAn0HBwhyphenhyphen0Oo4EhYU7jSbX6y9XsgbUnfM7H1KjBZgA1RH2ZtEa-dFeEJkysMdqcFPxU6rW10VOxmEgRpzv2mLPNLLz_-/s1600/cnidarians.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglFzPoa00uTDV7IpehNE_SonQ_IqomWJMrAyGfsMqvmAn0HBwhyphenhyphen0Oo4EhYU7jSbX6y9XsgbUnfM7H1KjBZgA1RH2ZtEa-dFeEJkysMdqcFPxU6rW10VOxmEgRpzv2mLPNLLz_-/s400/cnidarians.jpg" width="400" /></a><br />
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<b>Field characteristics:</b><br />
<ul style="text-align: left;">
<li>Radially symmetrical animals with tentacles.</li>
<li>Possess explosive, harpoon-like cells (cnidocytes).</li>
<li>May be solitary or colonial.</li>
<li>Solitary animals can be <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTmMfeNbebfwDEs9Hu9ciTTBIvjnI3YQqzCS8C3KqP1hPWJyLADfzz-0l6sIx8Euv9GMzoNv6t7axTRjVaISSsL3aA37TZ_ZSOh8YFjLLSapYuhGdUn0hb0z7f-M_ed7lz30Ji/s1600/Cerianthus14.jpg">sessile (flower-like polyp)</a> or <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiisod7TiFDOj4z0bDndvFVCT_EWQLWywi6WfT05uoG_FzumkL7Y8ZP5ihtTVui5KgctH_rVYu8tXdKuWVJz7TH5m7d_9w4OBjKfhgu6K-pNkKj9UnRZmlYj6z9HhUiDG7cUeyY/s1600/Mastigias1.jpg">motile (medusa, commonly called jellyfish)</a>.</li>
<li>Colonial animals build skeleton which does not display the radial symmetry, but individual animals in the colony still exhibit the radial symmetry.</li>
</ul>
<b>Examples:</b><br />
<ul style="text-align: left;">
<li><a href="http://tidechaser.blogspot.sg/2013/01/sea-anemones-actiniaria-singapore.html">Sea anemones</a></li>
<li><a href="http://tidechaser.blogspot.sg/2013/01/tube-anemones-ceriantharia-singapore.html">Tube anemones</a></li>
<li><a href="http://tidechaser.blogspot.sg/2013/01/mushroom-anemones-corallimorphs.html">Corallimorphs</a></li>
<li><a href="http://tidechaser.blogspot.sg/2012/12/hard-corals-scleractinia-singapore.html">Hard corals</a></li>
<li><a href="http://tidechaser.blogspot.sg/2013/01/zoanthids-zoantharia-of-singapore.html">Zoanthids</a></li>
<li><a href="http://tidechaser.blogspot.sg/2012/12/soft-corals-alcyonacea-singapore.html">Soft corals</a></li>
<li><a href="http://tidechaser.blogspot.sg/2013/01/blue-coral-heliopora-coerulea-singapore.html">Blue corals</a></li>
<li><a href="http://tidechaser.blogspot.sg/2013/01/sea-pens-pennatulacea-singapore.html">Sea pens</a></li>
<li><a href="http://tidechaser.blogspot.sg/2013/01/hydroids-hydrozoa-singapore.html">Hydroids</a></li>
<li><a href="http://tidechaser.blogspot.sg/2013/01/jellyfish-scyphozoa-singapore.html">Jellyfish</a></li>
</ul>
<b>May be confused with:</b><br />
<ul style="text-align: left;">
<li><a href="http://tidechaser.blogspot.sg/2013/03/sponges-porifera-singapore.html">Sponges</a> - Some sponges, depending on the growth form, may be mistaken for branching, boulder or encrusting hard corals and blue corals. Some may also be confused with soft corals. Sponges can be distinguished by the numerous tiny pores of varying sizes and the lack of a rock hard skeleton (to differentiate from hard corals).</li>
<li><a href="http://tidechaser.blogspot.sg/2013/01/hydroids-hydrozoa-singapore.html#hydromedusae"></a><a href="http://tidechaser.blogspot.com/2013/02/comb-jellies-ctenophora-singapore.html">Comb Jellies</a> - Scyphozoan jellyfish and <a href="http://tidechaser.blogspot.sg/2013/01/hydroids-hydrozoa-singapore.html#hydromedusae">hydromedusae</a> may be confused with comb jellies, but the latter only have two tentacles (if present) fringed with smaller tentacles. Most comb jellies also have eight strips (called comb rows) running down the length of their body.</li>
<li><a href="http://tidechaser.blogspot.sg/2013/01/moss-animals-bryozoa-singapore.html">Bryozoans</a> - <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhf3qdWVWpcJYbZSNBi1QX0073rt0Qb_0iKo2Ckq4nWl467l-b2TuXpc8YMFd4JioHQRCYGXeUNOhTaqkn4lDBOy6EkeufI1ujI5mTSuXCn8GJQ058I12TjXO5Y3ywURy-rZBb-/s1600/Bryozoan-3.jpg">Encrusting </a>or <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgd3xrLXEGYI-cb0tHHNoBQHi-qKFaL5wduuvsx43rZfHynab3o_OCpQLI_Ub5JrAVIBGfkZ1Yiw1Nl34fbqZ-zfkVpT5gteKbzmVPAyFKF6LaK2KLqU8R-WvXC9QA_1wxmsNQV/s1600/Bryozoan-13.jpg">lace-like</a> bryozoans may be mistaken for hard corals, while<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjsyXpN9dJfU0aaJbWctOtUNuqJxW7JjNBleI0gkQIHn8s_wpStq3gC8aBteukyRg3oFiGXRsiuE_W4fMsaDLcJoKDPfVRePIJU4w-VKNDAVGa7-tgVYvtXdd8OpqMUU9VqAlbX/s1600/Bryozoan+1.jpg"> tree-like bryozoans</a> may be mistaken for hydroids. A closer examination will usually reveal cell-like patterns in the bryozoans, which are the zooecia (or exoskeleton) of the individual zooids (the bryozoan animal). Some tree-like bryozoans, however, may lack the cell-like patterns, and instead, the zooids are lined tightly along the sides of the upper branches. Hydroids generally have <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiPt39YnSd5XyKTGmhNEKC7XfmhinPpjFCq21-0bh9pZafPkr5i2DQVPSM8Xl9ecdNLJiG10VzpBOC9LP5UiecdDoluBWuwrCA375_v7kkhY4iJxiCmBGjVOKU7CCpDlT9-dJRrjA/s1600/hydroid.jpg">polyps that are arranged by the sides of the branches at regular intervals</a>.</li>
<li><a href="http://tidechaser.blogspot.sg/2012/08/annelid-worms-annelida-singapore.html#Sabellidae">Fan worms</a> - Fan worms are sometimes mistaken for sea anemones and tube anemones due to their flower-like appearances. The tentacles of fan worms, however, are feather-like (with a main "stalk" in the middle and fine hairs lining the sides.)</li>
<li><a href="http://tidechaser.blogspot.sg/2012/08/horseshoe-worm-phoronida-singapore.html">Horseshoe worms</a> - Horseshoe worms may also be mistaken for sea anemones, or a <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIyxOCyx8wTnt417tEWes_BLgDSN7vaUxz3L14yMo7PWiEOrJX3YV3rrC_RSHy8y5-lm4s3WlWFUGpxJklGcgXbQ5eAI4PwFOUmZXZx27hZzSF_fSTM2ybJwgiZTXaXagsh2Kgcw/s1600/Phoronis-australis-2.jpg">cluster of them</a> may be mistaken for zoanthids or corallimorphs. Their crown of tentacles, however, are arranged in a somewhat horseshoe shape if viewed from the top, appearing like two separate spirals but are actually connected.</li>
<li><a href="http://tidechaser.blogspot.sg/2012/03/feather-star-crinoidea-of-singapore.html">Feather stars</a> - Due to the feather-like arms and pentaradial symmetry, feather stars may be mistaken for sea anemones by some people. They, however, lack the body column, and have claw-like arms on the underside.</li>
<li><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj1zGbISgrmCo00db27YAetwvQH80mj8QU07EcmxOTE3E8cLpOl7rYQ0QvimsAXCULRQp2jxxQsuJJ1CYSMfqPGYW0zL7DSuplglR6Wt3tUryw_RTIjLdnmt0RS2A9zHN7VhY8Dkg/s1600/seaweed.jpg">Seaweed</a> - Soft corals and hydroids may have plant-like appearances, but they lack the succulence of the latter. Also, the individual polyps will be radially symmetrical, and if they have retracted, there will be small bumps or holes on the surface of the colony housing them.
</li>
<li><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibInQ8Nk5P3fkBUExzTi1ZTU2oOwtakXfS_qz8oB1aKOdslpZXybf1hAFdGh-Pj1ibJ9BRs_vqBKqSvfSOjwfz2QOHH7af7VQkqCifgo9uFsjC5VwSrgnHFA7ib-J0DTuA4-UrtQ/s1600/rocks.jpg">Rocks</a> - Hard corals may be confused with rocks. They have have <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiPWvP8vVfdgBA48qkzeNUfWRfwrMtgCV7bjBJJktqh_LyLXCKFzIvCyXaL75pZWzM7ZU7jc7F5Cg3tMrOtSUURkKlsd8vfsGPW4mn8Jt8fYNOc05ohpIVAIJOyAOLsMgEUWftdZw/s1600/Parts-of-a-corallite.jpg"> regular depressions and patterns (forming the corallites)</a> on the surface though.</li>
</ul>
<div style="text-align: right;">
<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/01/cnidarians-cnidaria-singapore.html"><b>>> more</b></a></span></div>
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<b>4. <a href="http://tidechaser.blogspot.sg/2012/08/horseshoe-worm-phoronida-singapore.html">Horseshoe Worm (Phylum Phoronida)</a></b><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEids2F9jgMSZ3glu421DwAVe68hTcPdWXbYwvKFjuFhGzWXEr7CXTsQlhZLAUvLq9VxFlq-WPMqAwZhtNUUtXIjOPIC4WEYTjk-mzX-yQw0_zPNj35PNRK2XZESaW_U0vpfHlLi4g/s1600/Phoronis-australis.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEids2F9jgMSZ3glu421DwAVe68hTcPdWXbYwvKFjuFhGzWXEr7CXTsQlhZLAUvLq9VxFlq-WPMqAwZhtNUUtXIjOPIC4WEYTjk-mzX-yQw0_zPNj35PNRK2XZESaW_U0vpfHlLi4g/s400/Phoronis-australis.jpg" width="400" /></a>
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<br />
<b>Field characteristics:</b><br />
<ul style="text-align: left;">
<li>Live in tubes and with a crown of tentacles arranged in a somewhat horseshoe shape when viewed from the top.</li>
<li>The species recorded from Singapore <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKOSJm7FfrRyMM4GUMrSU3tP0d3EGFOgYhtV6WtvJXZ3Y7vv6fUD54FWvJx3aqxOE4bb7YYjfo8Kthcl5ThQLTv8nb19ChIdKVX9kAswvxAdAS52WQ5X6w0H1L1CEtmn-bAA-XiQ/s1600/Phoronis-australis1.jpg">lives commensally with various species of tube anemones from the family Cerianthidae</a> by boring into the walls of their tubes.</li>
</ul>
<b>May be confused with:</b><br />
<ul style="text-align: left;">
<li><a href="http://tidechaser.blogspot.sg/2012/08/annelid-worms-annelida-singapore.html#Sabellidae">Fan worms</a> - Fan worms are sometimes mistaken for horseshoe worms due to their flower-like appearances. The crown of tentacles of the horseshoe worm, however, is arranged in a somewhat horseshoe shape when viewed from the top, appearing like two separate spirals but are actually connected.</li>
<li><a href="http://tidechaser.blogspot.sg/2013/01/cnidarians-cnidaria-singapore.html">Cnidarians</a> - Due to the crown of tentacles, and their habit of congregating sometimes, horseshoe worms may be mistaken for sessile cnidarians, such as <a href="http://tidechaser.blogspot.sg/2013/01/sea-anemones-actiniaria-singapore.html">sea anemones</a>, <a href="http://tidechaser.blogspot.sg/2013/01/tube-anemones-ceriantharia-singapore.html">tube anemones</a>, <a href="http://tidechaser.blogspot.sg/2013/01/zoanthids-zoantharia-of-singapore.html">zoanthids</a> or <a href="http://tidechaser.blogspot.sg/2013/01/mushroom-anemones-corallimorphs.html">corallimorphs</a>.The crown of tentacles of the horseshoe worm, however, is arranged in a somewhat horseshoe shape when viewed from the top, appearing like two separate spirals but are actually connected.</li>
</ul>
<div style="text-align: right;">
<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2012/08/horseshoe-worm-phoronida-singapore.html"><b>>> more</b></a></span></div>
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<b>5. <a href="http://tidechaser.blogspot.sg/2013/01/moss-animals-bryozoa-singapore.html">Moss Animals (Phylum Bryozoa)</a></b><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYG8fbK7fs8lvDFRVx1Iloyk0E3HKfWT4L0FVgI6qJw1N8NhBzoiIjExlufBaNYEuwkFJkyDTjHhO7hK8o0ke3nNTF9UkxPcPX0PlfH-4rVgnx5TZcuwFtS-gO4Ff_BD6Vo4sA/s1600/Bryozoa.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYG8fbK7fs8lvDFRVx1Iloyk0E3HKfWT4L0FVgI6qJw1N8NhBzoiIjExlufBaNYEuwkFJkyDTjHhO7hK8o0ke3nNTF9UkxPcPX0PlfH-4rVgnx5TZcuwFtS-gO4Ff_BD6Vo4sA/s400/Bryozoa.jpg" width="400" /></a>
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<br />
<b>Field characteristics:</b><br />
<ul style="text-align: left;">
<li>Form plant-like, lace-like or encrusting colonies.</li>
<li>The individual bryozoan animal (or zooid) usually lives in a "chamber" (or zooecium), which is a protective chitinous or calcareous exoskeleton.</li>
<li>A closer examination will usually reveal <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg2p6NPaAlDSyUzF3MNb8yOT8oe-G10PmsbWj0VWdobiDQV5V70eIvAL9nfQ-x4x6Vbf5Jar5FktDQFKuAKGipFFB8pe3vHTRoNbcPUbnHXcxZS0yjpRxA_SOOwdugp5C1Qoay4/s1600/Bryozoan-4.jpg">cell-like patterns</a> in the bryozoans, which are the zooecia (or exoskeleton) of the individual zooids (the bryozoan animal). Some tree-like bryozoans (see <a href="http://www.bryozoa.net/ctenostomata/vesiculariidae/amatwil1.gif">diagram from bryozoa.net</a>), however, may lack the cell-like patterns, and instead, the zooids are lined tightly along the sides of the upper branches.</li>
</ul>
<b>May be confused with:</b><br />
<ul style="text-align: left;">
<li><a href="http://tidechaser.blogspot.sg/2013/01/cnidarians-cnidaria-singapore.html">Cnidarians</a> - <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhf3qdWVWpcJYbZSNBi1QX0073rt0Qb_0iKo2Ckq4nWl467l-b2TuXpc8YMFd4JioHQRCYGXeUNOhTaqkn4lDBOy6EkeufI1ujI5mTSuXCn8GJQ058I12TjXO5Y3ywURy-rZBb-/s1600/Bryozoan-3.jpg">Encrusting </a>or <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgd3xrLXEGYI-cb0tHHNoBQHi-qKFaL5wduuvsx43rZfHynab3o_OCpQLI_Ub5JrAVIBGfkZ1Yiw1Nl34fbqZ-zfkVpT5gteKbzmVPAyFKF6LaK2KLqU8R-WvXC9QA_1wxmsNQV/s1600/Bryozoan-13.jpg">lace-like</a> bryozoans may be mistaken for hard corals, while<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjY_FhVoBy9c2Q4YMg-h-zZQbihjFZBWo8kLSNkh_SVgLauL1o1ciI3EC_c44sDn54JScW3YgWUREEZ4pe5DXgZeERgSuBKHAOTDIWfwTtz47thz0BXniuod1typgBLt08DfYke/s1600/Bryozoan-8.jpg"> plant-like bryozoans</a> may be mistaken for <a href="http://tidechaser.blogspot.sg/2013/01/hydroids-hydrozoa-singapore.html">hydroids</a>. A closer examination will usually reveal cell-like patterns in the bryozoans, which are the zooecia (or exoskeleton) of the individual zooids (the bryozoan animal). Some plant-like bryozoans, however, may lack the cell-like patterns, and instead, the zooids are lined tightly along the sides of the upper branches. Hydroids generally have <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiPt39YnSd5XyKTGmhNEKC7XfmhinPpjFCq21-0bh9pZafPkr5i2DQVPSM8Xl9ecdNLJiG10VzpBOC9LP5UiecdDoluBWuwrCA375_v7kkhY4iJxiCmBGjVOKU7CCpDlT9-dJRrjA/s1600/hydroid.jpg">polyps that are arranged by the sides of the branches at regular intervals</a>.</li>
<li><a href="http://tidechaser.blogspot.sg/2013/05/tunicates-ascidians-salps-singapore.html">Tunicates</a> - Colonial tunicates are sometimes mistaken for bryozoans. To differentiate them from the latter, take a closer look to spot the <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJJhbszv3Ag5Uwj8nPktCLevKxFbSFXZJ-uvlnymq_D6ruErclN0zxpBWoCqXn6WqLhM2ANImF_CTT7d-ty6GNwxWuuUsPhbKjMp5tN5Ie8BlCx2XKUyxrAEQj7e7Kk8eKBMrB/s1600/zooids.jpg">individual zooids</a>, which lack the cell-like patterns.</li>
<li><a href="http://tidechaser.blogspot.sg/2013/03/sponges-porifera-singapore.html">Sponges</a> - Encrusting or lace-like bryozoans may be mistaken to be sponges, but the latter lack the cell-like patterns found on the bryozoan colonies.</li>
<li><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj1zGbISgrmCo00db27YAetwvQH80mj8QU07EcmxOTE3E8cLpOl7rYQ0QvimsAXCULRQp2jxxQsuJJ1CYSMfqPGYW0zL7DSuplglR6Wt3tUryw_RTIjLdnmt0RS2A9zHN7VhY8Dkg/s1600/seaweed.jpg">Seaweed</a>
- Some bryozoans have plant-like appearances, but they lack the succulence of the latter. Also, a closer examination will usually reveal <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjsyXpN9dJfU0aaJbWctOtUNuqJxW7JjNBleI0gkQIHn8s_wpStq3gC8aBteukyRg3oFiGXRsiuE_W4fMsaDLcJoKDPfVRePIJU4w-VKNDAVGa7-tgVYvtXdd8OpqMUU9VqAlbX/s1600/Bryozoan+1.jpg">cell-like or segmented patterns</a> in the bryozoans.</li>
<li><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjj2t1Ajql8J4DkdEZL-GmNbyHx3pTGonM2oldJZM0y_MnHP4PeWTSOgiTBjStqC2ru-VaYk0It3ybbjgjijZv9mmx_TmggICUVea_zkA-zHGsmNlssvTT5N5CfpjxbEvRJnjm2jw/s1600/eggs.jpg">Mollusc eggs</a> - The egg ribbons and capsules of some molluscs may be confused with bryozoans, but they lack the cell-like patterns as well.</li>
</ul>
<div style="text-align: right;">
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<b>6. <a href="http://tidechaser.blogspot.sg/2013/02/lamp-shells-brachiopoda-singapore.html">Lamp Shells (Phylum Brachiopoda)</a></b><br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiSXqDZoregddZPpIMHGO_Sbdf5oKCdW93nyE4eqXaRClFbrlHqo85aeBr3gTHfAFnjCIXtMY11o3TLbgBecHG4hQ0rDzVpLCHyONEgJlT0yxG91OkGGpwPVwv_HVWK-gpJxLFa/s1600/Brachiopod.jpg"><img alt="Lamp shell (Lingula sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiSXqDZoregddZPpIMHGO_Sbdf5oKCdW93nyE4eqXaRClFbrlHqo85aeBr3gTHfAFnjCIXtMY11o3TLbgBecHG4hQ0rDzVpLCHyONEgJlT0yxG91OkGGpwPVwv_HVWK-gpJxLFa/s400/Brachiopod.jpg" title="Lamp shell (Lingula sp.)" width="400" /></a>
<br />
<br />
<b>Field characteristics:</b><br />
<ul style="text-align: left;">
<li>Appear clam-like with a two-part shell, comprising a dorsal (or "upper") valve and a ventral (or "lower") valve.</li>
<li>The two valves are usually not symmetrical, but the line of symmetry is perpendicular to the hinge line.</li>
<li>Many species, such as the one recorded from Singapore anchors itself in soft substrates with a stalk-like structure called a pedicle.</li>
</ul>
<b>May be confused with:</b><br />
<ul style="text-align: left;">
<li><a href="http://tidechaser.blogspot.sg/2012/12/marine-bivalves-of-singapore.html">Bivalves</a> - Lamp shells have a two-part shell, and hence are often confused with bivalves. Bivalves, however, have a ligament that joins the valves near the hinge, which forces the two valves open when the adductor muscles relax. Lamp shells lack this ligament, and hence their shells often remain close even after the animal is dead. And for bivalves, if a line of symmetry is present, it is usually parallel to the hinge line, while for the lamp shells the line of symmetry is perpendicular to the hinge line.</li>
</ul>
<div style="text-align: right;">
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<b>7. <a href="http://tidechaser.blogspot.sg/2013/07/acoels-acoelomorpha-flatworms-singapore.html">Acoel Worms (Phylum Acoelomorpha)</a></b><br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjf7J15YrDisigYylNUOxqiccj1RpOdXTacBMkNssWFiEm_L0AqicUU8dbpoFXGyg-y11mNajHzeRYRLs003W2fvKN6Ur_GXrZJtBIFw-E_T7YJDKnsN0dqTb7DklwjXW0Nwvk8vA/s1600/Waminoa.jpg"><img alt="Waminoa Acoel Worms (Waminoa sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjf7J15YrDisigYylNUOxqiccj1RpOdXTacBMkNssWFiEm_L0AqicUU8dbpoFXGyg-y11mNajHzeRYRLs003W2fvKN6Ur_GXrZJtBIFw-E_T7YJDKnsN0dqTb7DklwjXW0Nwvk8vA/s400/Waminoa.jpg" title="Acoel Worms (Phylum Acoelomorpha)" width="400" /></a>
<br />
<br />
<b>Field characteristics:</b><br />
<ul style="text-align: left;">
<li>Appear flat, bilaterally symmetrical, soft-bodied and unsegmented.</li>
<li>Do not have a gut cavity.</li>
<li>Have a distinctive balance sensory receptor (made up of a large cell bearing a calcareous body), appearing like a round spot near the front end. This is usually hard to see without a hand lens though.</li>
<li>The species recorded in Singapore are small (typically less than 0.5cm) and congregate on <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjeGCK87TVI6WFBnyLPJYYo9x-rcfrpti2mzdlMn1cu8CWKtLFVApPKkX8zfE1iXnokRC0zUr93z35n9aAYkqRkPUGIL7sHBIZKB_wmO_h2iHxbG5imuoi-HBHUpsBBvcaAHTZsyQ/s1600/Acoel2.jpg">hard corals</a> and <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgPS2QwNPlN5Voze9CX0PAiy1cNFNDcJxhx5csa1iZujDPaLxqDER7uX6rHnSMYbv7E4SAagTVcF-SdAW9dJLUGsmNgU0UtySj4SzG_tfB5SSBHPhKqvafN-dt_lXk8D1XQ7J0yNw/s1600/Acoel.jpg">corallimoprhs</a>.</li>
</ul>
<b>May be confused with:</b><br />
<ul style="text-align: left;">
<li><a href="http://tidechaser.blogspot.sg/2012/08/flatworms-platyhelminthes-singapore.html">Flatworms</a> - Acoels appear like tiny flatworms, but they have a distinctive balance sensory receptor near the front end, appearing like a round dot when viewed under a hand lens. The species recorded in Singapore congregate on hard corals and corallimorphs.</li>
</ul>
<div style="text-align: right;">
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<b>8. <a href="http://tidechaser.blogspot.sg/2012/04/echinoderms-of-singapore.html">Echinoderms (Phylum Echinodermata)</a></b><br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhCYFSO4LEXf8uVs_S_uqNAofUTTSi85UlILhabk-G55gWDqX6UhkWX8S0itGznY82oY1RhMNkLkOzHvbP4Yuj-UtY0ZSsetPQ33zuP04doZPvy3f-cpxPTe02pXAfLnPBKUN-UFQ/s1600/Echinodermata.jpg"><img alt="Echinoderms (Phylum Echinodermata)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhCYFSO4LEXf8uVs_S_uqNAofUTTSi85UlILhabk-G55gWDqX6UhkWX8S0itGznY82oY1RhMNkLkOzHvbP4Yuj-UtY0ZSsetPQ33zuP04doZPvy3f-cpxPTe02pXAfLnPBKUN-UFQ/s400/Echinodermata.jpg" title="Echinoderms (Phylum Echinodermata)" width="400" /></a><br />
<br />
<b>Field characteristics:</b><br />
<ul style="text-align: left;">
<li>Marine animals with penta-radial symmetry, i.e. each echinoderm can be divided into 5 equal parts, at least in some stage of life.</li>
<li>Possess a water vascular system, which is a network of water-filled vessels within their body, terminating usually at numerous tiny <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiSwIrBC5Xun5YbES5NrbhxuIeODz1PHptQyp6lWs9hp_cU85nAOLlq28_B6svFCuVvhyphenhyphenLLeQt7FoOa02TW-dPsc1AtFrq4bjEqfPFKL_Dpu9XNNtZFjNplsgAyA8krsZIvUwOBXw/s1600/Luidia.jpg">tube feet</a> on the undersides.</li>
</ul>
<b>Examples:</b><br />
<ul style="text-align: left;">
<li><a href="http://tidechaser.blogspot.sg/2012/03/sea-stars-class-asteroidea-of-singapore.html">Sea stars</a></li>
<li><a href="http://tidechaser.blogspot.sg/2012/03/feather-star-crinoidea-of-singapore.html">Feather stars</a></li>
<li><a href="http://tidechaser.blogspot.sg/2012/03/brittle-stars-ophiuroidea-of-singapore.html">Brittle stars</a></li>
<li><a href="http://tidechaser.blogspot.sg/2012/04/sea-cucumbers-holothuroidea-of.html">Sea cucumbers</a></li>
<li><a href="http://tidechaser.blogspot.sg/2012/03/sea-urchins-echinoidea-of-singapore.html">Sea urchins & sand dollars</a></li>
</ul>
<ul style="text-align: left;">
</ul>
<b>May be confused with:</b><br />
<ul style="text-align: left;">
<li><a href="http://tidechaser.blogspot.sg/2012/05/marine-slugs-gastropoda-singapore.html">Marine slugs</a> - Some smaller sea cucumbers may be mistaken for marine slugs, but can be distinguished from the latter by having oral tentacles and tube feet.</li>
<li><a href="http://tidechaser.blogspot.sg/2013/01/sea-anemones-actiniaria-singapore.html">Sea anemones</a> - Feather stars are occasionally mistaken for sea anemones due to their long arms. They, however, lack the body column, and have claw-like arms on the underside. Some sea cucumbers, especially <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgRg-Qmki2T4X72LWEGNFpr-Aa3AeeF0q0op_N59ZdOrrUTSAeXxiN-CKHOssum0vcao-Nh-z2tL6EWU8cfz3vIWfg41VbPJkIWzOdSLZbrN40u4DYZV5a534If6tOGycPHMBPePw/s1600/Phyllophorus1.jpg">the burrowing ones</a>, may be mistaken for sea anemones too when they <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglYo7LnimXNjkRGqrybrySe91vdcuphaLmwvyC1sfy-LETJ74hw9jMf7NWZbS5YZta0L-5uvHHG7uXemDYjkFBpgc6qjKl7G05hhiQ7nyWqvlIUVestzOO4aT9ljaih4OvOX8NlQ/s1600/Colochirus-quadrangularis.jpg">extend their oral tentacles</a> to feed. They have <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbKDcDpCk-Jmx3oEHTy1ZZncVqPBcXaxjk3M9v65mC9pT0nnLAi5w7Oz2fmCx8gLilyX5afZqDxre6xFfJURwezlyF6YerK4oqwfIEI5VgG64durChhecM0411melIzfjRX8Mmzg/s1600/Stichopus-ocellatus1.jpg">an anus</a> though, which sea anemones lack.</li>
<li><a href="http://tidechaser.blogspot.sg/2012/08/annelid-worms-annelida-singapore.html">Annelid worms</a> - Some sea cucumbers may be mistaken for <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjJX-2SASMNfA0ZfAHMrvtXhoww8kE8nGJNtbjA0xO12oWfhgywp_K2MKMg492o_Yanh66wFEuNHvgijMgsb3rgcWDRmZUEMCbb1Ko7NZUOmqTMLDeb3FJd57gLRbHfRX2sVUEOsw/s1600/oligochaete.jpg">earthworms</a>, <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh8cQSY8KOyIQFtST7vIOz6n3dleJUHXnexfPhaMrqViVhWjyFdkOT9ZVUdPMAds0psGYfo_iFABlmNcdtGfVw0r_FifKPzrRyPuOugJ3xVp4E9lKPAgEyxJv_T3NneGLAM-zq3Jg/s1600/peanut-worm.jpg">peanut worms</a> and other annelid worms due to their long and slim bodies, but can be distinguished by their oral tentacles and tube feet.</li>
</ul>
<div style="text-align: right;">
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<b>9. <a href="http://tidechaser.blogspot.sg/2013/02/acorn-worms-hemichordata-singapore.html">Hemichordates (Phylum Hemichordata)</a></b><br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjsiAWB22YP1vtxnRlBqKUnboND9SqmFnKi5Z-TlB_kr6RuGJm2LySzp1kmXBJwqOZ5cAQ8CE5gpnoqJmjjrq8aPCyltsr3k5T7sK4WNa2Yre0PLbf48WO6LyeFISagQLlBTeH3/s1600/Acorn-worm.jpg"><img alt="Acorn Worm Cast" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjsiAWB22YP1vtxnRlBqKUnboND9SqmFnKi5Z-TlB_kr6RuGJm2LySzp1kmXBJwqOZ5cAQ8CE5gpnoqJmjjrq8aPCyltsr3k5T7sK4WNa2Yre0PLbf48WO6LyeFISagQLlBTeH3/s400/Acorn-worm.jpg" title="Acorn Worm Cast" width="400" /></a><br />
<br />
<b>Field characteristics:</b><br />
<ul style="text-align: left;">
<li>Appear worm-like animals with a three-part body - the front end, followed by a collar, and a posterior trunk.</li>
<li>Swallow sand or mud and digest the tiny organic particles inside, and excrete the <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjsiAWB22YP1vtxnRlBqKUnboND9SqmFnKi5Z-TlB_kr6RuGJm2LySzp1kmXBJwqOZ5cAQ8CE5gpnoqJmjjrq8aPCyltsr3k5T7sK4WNa2Yre0PLbf48WO6LyeFISagQLlBTeH3/s1600/Acorn-worm.jpg">processed sediment in coils (called cast)</a> during low tide. Usually, only the casts left behind during low tide are seen.</li>
<li>The body is very fragile and breaks apart when dug out from its burrow.</li>
</ul>
<b>May be confused with:</b><br />
<ul style="text-align: left;">
<li><a href="http://tidechaser.blogspot.sg/2012/08/annelid-worms-annelida-singapore.html">Annelid worms</a> - Hemichordates seen on the shore may be mistaken for <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjJX-2SASMNfA0ZfAHMrvtXhoww8kE8nGJNtbjA0xO12oWfhgywp_K2MKMg492o_Yanh66wFEuNHvgijMgsb3rgcWDRmZUEMCbb1Ko7NZUOmqTMLDeb3FJd57gLRbHfRX2sVUEOsw/s1600/oligochaete.jpg">earthworms</a>, <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh8cQSY8KOyIQFtST7vIOz6n3dleJUHXnexfPhaMrqViVhWjyFdkOT9ZVUdPMAds0psGYfo_iFABlmNcdtGfVw0r_FifKPzrRyPuOugJ3xVp4E9lKPAgEyxJv_T3NneGLAM-zq3Jg/s1600/peanut-worm.jpg">peanut worms</a> and other annelid worms due to their long and slim bodies. The cast resembles those made by <a href="http://tidechaser.blogspot.sg/2012/08/annelid-worms-annelida-singapore.html#Arenicolidae">lug worms</a>. The only sure way to distinguish hemichordates is to check for the three-part body plan.</li>
</ul>
<div style="text-align: right;">
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<b>10. <a href="http://tidechaser.blogspot.sg/2012/08/annelid-worms-annelida-singapore.html">Annelid Worms (Phylum Annelida)</a></b><br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg-kopDN4Ts7YDLaUKV24XhKzKCA-Fd-o-rBoHoFXP6-6tykoQfd5du5Ow7Gw7JT6dQ4UYm-k0jLmoDP0IBiLsSrniQxIENoLKSMcObZ0kjAbF_u3C3PsNYkC2oSFTlxWanbz_gTw/s1600/Annelida.jpg"><img alt="Annelid Worms (Phylum Annelida)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg-kopDN4Ts7YDLaUKV24XhKzKCA-Fd-o-rBoHoFXP6-6tykoQfd5du5Ow7Gw7JT6dQ4UYm-k0jLmoDP0IBiLsSrniQxIENoLKSMcObZ0kjAbF_u3C3PsNYkC2oSFTlxWanbz_gTw/s400/Annelida.jpg" title="Annelid Worms (Phylum Annelida)" width="400" /></a>
<br />
<br />
<b>Field characteristics:</b><br />
<ul style="text-align: left;">
<li>Bilaterally symmetrical worms which may or may not be segmented.</li>
<li>Segmented species have a body comprising identical segments (excluding the head and tail) containing the same set of organs, and in some cases, external structures used for locomotion.</li>
<li>Unsegmented annelids are believed to have lost the segments through evolution, and include the <a href="http://tidechaser.blogspot.sg/2012/08/annelid-worms-annelida-singapore.html#Echiura">spoon worms</a> with a flattened proboscis resembling a spoon on their front ends, and the <a href="http://tidechaser.blogspot.sg/2012/08/annelid-worms-annelida-singapore.html#Sipuncula">peanut worms</a> with a body comprising an unsegmented trunk and a retractable structure called an "introvert".</li>
</ul>
<b>May be confused with:</b><br />
<ul style="text-align: left;">
<li><a href="http://tidechaser.blogspot.sg/2013/02/acorn-worms-hemichordata-singapore.html">Hemichordates</a> - Hemichordates may be mistaken for peanut worms and other annelid worms due to their long and slim bodies. The cast resembles those made by lug worms. The only sure way to distinguish hemichordates is to check for the three-part body plan.</li>
<li><a href="http://tidechaser.blogspot.sg/2013/06/arthropods-arthropoda-singapore.html">Arthropods</a> - Due to their segmented bodies, annelid worms are easily confused with arthropods that have elongate bodies, such as <a href="http://tidechaser.blogspot.sg/2013/06/millipedes-diplopoda-singapore.html">millipedes</a>, <a href="http://tidechaser.blogspot.sg/2013/06/centipedes-chilopoda-singapore.html">centipedes</a>, <a href="http://tidechaser.blogspot.sg/2013/06/arthropods-arthropoda-singapore.html#Symphyla">symphylans</a> and <a href="http://tidechaser.blogspot.sg/2013/06/insects-insecta-singapore.html#Lepidoptera">caterpillars of moths and butterflies</a>. Annelids, however, lack true segmented legs which the arthropods possess, and at most have bristle-like structures to aid with movement.</li>
<li><a href="http://tidechaser.blogspot.sg/2013/02/velvet-worm-onychophora-singapore.html">Velvet worms</a> - Velvet worms have elongate bodies as well, but they have true legs which the annelids lack.</li>
<li><a href="http://tidechaser.blogspot.sg/2012/08/ribbon-worms-nemertea-singapore.html">Ribbon worms</a> - Some ribbon worms, especially the <a href="http://tidechaser.blogspot.sg/2012/08/ribbon-worms-nemertea-singapore.html#terrestrial">terrestrial ones</a>, can be confused with <a href="http://tidechaser.blogspot.sg/2012/08/annelid-worms-annelida-singapore.html#Oligochaeta">earthworms</a> and <a href="http://tidechaser.blogspot.sg/2012/08/annelid-worms-annelida-singapore.html#Hirudinea">leeches</a>. Ribbon worms, however, do not have segmented bodies, unlike the earthworms and leeches.</li>
<li><a href="http://tidechaser.blogspot.sg/2012/04/sea-cucumbers-holothuroidea-of.html">Sea cucumbers</a> - Some sea cucumbers may be mistaken for earthworms, peanut worms and other annelid worms due to their long and slim bodies, but can be distinguished by their oral tentacles and tube feet.</li>
<li><a href="http://tidechaser.blogspot.sg/2012/12/polyplacophora-chitons-of-singapore.html">Chitons</a> - Short-bodied annelid worms, such as <a href="http://tidechaser.blogspot.sg/2012/08/annelid-worms-annelida-singapore.html#Polynoidae">scale worms</a>, can be confused with chitons as both are usually found on rocky shores. Chitons, however, have an-eight-part shell on their back, while scale worms have numerous overlapping plated on their back.</li>
</ul>
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<b>11. <a href="http://tidechaser.blogspot.sg/2012/08/ribbon-worms-nemertea-singapore.html">Ribbon Worms (Phylum Nemertea)</a></b><br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglhBgJNpI1tTf1Ce4whw5kDq4IIb9roSwr_tbIbockNs9aUlRSqO50b-4HOrwq22bSMHizfYnkJGxTqfCovqJfFUSEO9_2I41Wf5vUeeRrx8JxssTWrCKQo_DaOu9dSct3Rb7YKA/s1600/Nemertea.jpg"><img alt="Ribbon Worms (Phylum Nemertea)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglhBgJNpI1tTf1Ce4whw5kDq4IIb9roSwr_tbIbockNs9aUlRSqO50b-4HOrwq22bSMHizfYnkJGxTqfCovqJfFUSEO9_2I41Wf5vUeeRrx8JxssTWrCKQo_DaOu9dSct3Rb7YKA/s400/Nemertea.jpg" title="Ribbon Worms (Phylum Nemertea)" width="400" /></a><br />
<br />
<b>Field characteristics:</b><br />
<ul style="text-align: left;">
<li> Soft-bodied, bilaterally symmetrical animals which are mostly long, thin and flat.</li>
<li>Some terrestrial species may appear <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJOowKMHGWdCxscO8mXmfewLVh1lmLeMz6pDQbT8VX2D_HPArImKHzDIIGo53bVMuI5OQxDusfTUy4B1GQ_9qH3OAoCt3LRgqu60UMV_hqB4mLcskKixp-IAK3nfLQwf7rl_Xm/s1600/Terrestrial-ribbon-worm.jpg">more cylindrical than flat</a>, while others appear short and wide.</li>
<li>Have an eversible proboscis which can shoot out just above the mouth to capture/retrieve their food.</li>
</ul>
<b>May be confused with:</b><br />
<ul style="text-align: left;">
<li><a href="http://tidechaser.blogspot.sg/2012/08/annelid-worms-annelida-singapore.html">Annelid worms</a> - Some ribbon worms, especially the <a href="http://tidechaser.blogspot.sg/2012/08/ribbon-worms-nemertea-singapore.html#terrestrial">terrestrial ones</a>, can be confused with <a href="http://tidechaser.blogspot.sg/2012/08/annelid-worms-annelida-singapore.html#Oligochaeta">earthworms</a> and <a href="http://tidechaser.blogspot.sg/2012/08/annelid-worms-annelida-singapore.html#Hirudinea">leeches</a>. Ribbon worms, however, do not have segmented bodies, unlike the earthworms and leeches.</li>
<li><a href="http://tidechaser.blogspot.sg/2012/08/flatworms-platyhelminthes-singapore.html">Flatworms</a> - Shorter ribbon worms may be mistaken for flatworms. Marine species are generally not paper thin like the marine flatworms, and terrestrial ribbon worms are more cylindrical than the terrestrial flatworms. In some cases, it can be extremely hard to distinguish them without looking at the internal parts.</li>
</ul>
<div style="text-align: right;">
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<b>12. <a href="http://tidechaser.blogspot.sg/2012/08/flatworms-platyhelminthes-singapore.html">Flatworms (Phylum Platyhelminthes)</a></b><br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhS2MjYBecqeQSBdbywbZsnhANVenebY68j0mdPigqQkC636MPwRL_W14qUmzroI7MJTuO-E3U057nSEEALkIxgjF37JOmXTEMz7FHpVTH7TlpLUIGmg4nf_eWtTlaSCXSoJHTeKA/s1600/flatworm.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhS2MjYBecqeQSBdbywbZsnhANVenebY68j0mdPigqQkC636MPwRL_W14qUmzroI7MJTuO-E3U057nSEEALkIxgjF37JOmXTEMz7FHpVTH7TlpLUIGmg4nf_eWtTlaSCXSoJHTeKA/s400/flatworm.jpg" width="400" /></a><br />
<br />
<b>Field characteristics:</b><br />
<ul style="text-align: left;">
<li>Unsegmented worms with soft and bilaterally symmetrical bodies.</li>
<li>Most species have very flat bodies.</li>
<li>Most marine species appear leaf-shaped, while terrestrial species recorded in Singapore have hammer-shaped heads.</li>
</ul>
<b>May be confused with:</b><br />
<ul style="text-align: left;">
<li><a href="http://tidechaser.blogspot.sg/2013/07/acoels-acoelomorpha-flatworms-singapore.html">Acoels</a> - Acoels appear like tiny flatworms, but they have a tiny distinctive balance sensory receptor (appearing like a round dot) near the front end when viewed under a hand lens, and the species recorded in Singapore congregate on hard corals and corallimorphs.</li>
<li><a href="http://tidechaser.blogspot.sg/2012/08/ribbon-worms-nemertea-singapore.html">Ribbon worms</a> - Shorter ribbon worms may be mistaken for flatworms. Marine species are generally not paper thin like the marine flatworms, and terrestrial ribbon worms are more cylindrical than the terrestrial flatworms. In some cases, it can be extremely hard to distinguish them without looking at the internal parts.</li>
</ul>
<div style="text-align: right;">
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<b>13. <a href="http://tidechaser.blogspot.sg/2013/02/velvet-worm-onychophora-singapore.html">Velvet Worms (Phylum Onychophora)</a></b><br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgBAMycts-gNaC2RrNH7Rr_ssRoyDhyphenhyphenmPDhckLen8gxmjI0sdOC4byJU94Vfx-h4Xt_UjlY6hUdWT6oYFd_nivSXEYnUDAJpj4ttBc9xlFgzmRwtAHF2Rlo6a5HWhI4aMDL5cOmAQ/s1600/Onychophora.jpg"><img alt="Velvet Worms (Phylum Onychophora)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgBAMycts-gNaC2RrNH7Rr_ssRoyDhyphenhyphenmPDhckLen8gxmjI0sdOC4byJU94Vfx-h4Xt_UjlY6hUdWT6oYFd_nivSXEYnUDAJpj4ttBc9xlFgzmRwtAHF2Rlo6a5HWhI4aMDL5cOmAQ/s400/Onychophora.jpg" title="Velvet Worms (Phylum Onychophora)" width="400" /></a><br />
<br />
<b>Field characteristics:</b><br />
<ul style="text-align: left;">
<li>Terrestrial animals with elongate, segmented bodies and numerous pairs of walking legs.</li>
<li>Each leg has a pair of claws.</li>
<li>They lack a rigid exoskeleton, and instead, the body cavity is filled with a fluid to make them firm.</li>
</ul>
<b>May be confused with:</b><br />
<ul style="text-align: left;">
<li><a href="http://tidechaser.blogspot.sg/2013/02/velvet-worm-onychophora-singapore.html">Annelid worms</a> - Velvet worms have elongate segmented bodies like many annelids, but they have true legs which the latter lack.</li>
<li><a href="http://tidechaser.blogspot.sg/2013/06/arthropods-arthropoda-singapore.html">Arthropods</a> - Velvet worms are easily confused with arthropods that have elongate bodies, such as <a href="http://tidechaser.blogspot.sg/2013/06/millipedes-diplopoda-singapore.html">millipedes</a>, <a href="http://tidechaser.blogspot.sg/2013/06/centipedes-chilopoda-singapore.html">centipedes</a>, <a href="http://tidechaser.blogspot.sg/2013/06/arthropods-arthropoda-singapore.html#Symphyla">symphylans</a> and <a href="http://tidechaser.blogspot.sg/2013/06/insects-insecta-singapore.html#Lepidoptera">caterpillars of moths and butterflies</a>. They, however, lack the rigid exoskeleton of the arthropods, and have a pair of claws at the tip of each leg.</li>
</ul>
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<b>14. <a href="http://tidechaser.blogspot.sg/2013/06/arthropods-arthropoda-singapore.html">Arthropods (Phylum Arthropoda)</a></b><br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhl_rgjKrSER2glwkw6UbFbPVanNlOJ4qHnAAx1P2t93kT_YfrRoHpIgo6dAK-2gHEYfxjuIMU2I6BcaWW03QQNOVPW32jrvlIU2LRujqWtnxnA5X295I7taeyQBv_i9vkSOyeHpw/s1600/Arthropoda.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhl_rgjKrSER2glwkw6UbFbPVanNlOJ4qHnAAx1P2t93kT_YfrRoHpIgo6dAK-2gHEYfxjuIMU2I6BcaWW03QQNOVPW32jrvlIU2LRujqWtnxnA5X295I7taeyQBv_i9vkSOyeHpw/s400/Arthropoda.jpg" width="400" /></a>
<br />
<br />
<b>Field characteristics:</b><br />
<ul style="text-align: left;">
<li>Bilaterally symmetrical animals with segmented bodies and jointed (or segmented) limbs.</li>
<li>The body is enclosed in an external skeleton (or exoskeleton) composed largely of chitin.</li>
</ul>
<b>Examples:</b><br />
<ul style="text-align: left;">
<li><a href="http://tidechaser.blogspot.sg/2013/06/millipedes-diplopoda-singapore.html">Millipedes</a></li>
<li><a href="http://tidechaser.blogspot.sg/2013/06/centipedes-chilopoda-singapore.html">Centipedes</a></li>
<li><a href="http://tidechaser.blogspot.sg/2013/06/arthropods-arthropoda-singapore.html#Symphyla">Symphylans</a></li>
<li><a href="http://tidechaser.blogspot.sg/2013/06/horseshoe-crabs-merostomata-limulidae.html">Horseshoe crabs</a></li>
<li><a href="http://tidechaser.blogspot.sg/2013/06/spiders-scorpions-arachnida-singapore.html">Arachnids</a></li>
<li><a href="http://tidechaser.blogspot.sg/2013/06/arthropods-arthropoda-singapore.html#Pycnogonida">Sea spiders</a></li>
<li><a href="http://tidechaser.blogspot.sg/2013/06/insects-insecta-singapore.html">Insects</a></li>
<li><a href="http://tidechaser.blogspot.sg/2013/06/arthropods-arthropoda-singapore.html#Entognatha">Springtails</a></li>
<li><a href="http://tidechaser.blogspot.sg/2013/06/malacostracans-malacostraca-singapore.html">Malacostracans</a> (<a href="http://tidechaser.blogspot.sg/2013/07/true-crabs-brachyura-singapore.html">crabs</a>, <a href="http://tidechaser.blogspot.sg/2013/07/shrimps-caridea-singapore.html">shrimps</a> and <a href="http://tidechaser.blogspot.sg/2013/06/malacostracans-malacostraca-singapore.html">others</a>)</li>
<li><a href="http://tidechaser.blogspot.sg/2013/06/barnacles-cirripedia-singapore.html">Barnacles</a></li>
</ul>
<b>May be confused with:</b><br />
<ul style="text-align: left;">
<li><a href="http://tidechaser.blogspot.sg/2013/02/velvet-worm-onychophora-singapore.html">Annelid worms</a> - Due to their segmented bodies, annelid worms are easily confused with arthropods that have elongate bodies, such as millipedes, centipedes, symphylans and <a href="http://tidechaser.blogspot.sg/2013/06/insects-insecta-singapore.html#Lepidoptera">caterpillars of moths and butterflies</a>. Annelids, however, lack true segmented legs which the arthropods possess, and at most have bristle-like structures to aid with movement.</li>
<li><a href="http://tidechaser.blogspot.sg/2013/02/velvet-worm-onychophora-singapore.html">Velvet worms</a> - Velvet worms are easily confused with arthropods with elongate bodies as well. They, however, lack the rigid exoskeleton of the arthropods, and have a pair of claws at the tip of each leg.</li>
<li><a href="http://tidechaser.blogspot.sg/2012/12/molluscs-mollusca-of-singapore.html">Molluscs</a> - Barnacles may be easily confused with <a href="http://tidechaser.blogspot.sg/2012/09/limpets-nacellidae-lottiidae.html">limpets</a>, which also have conical shells. They are, however, permanently fixed on hard structures, while limpets are motile. Also, the wall of the barnacle's shell has numerous holes and gaps internally (much like a sponge!), holding many pockets of air for heat insulation. Barnacles may also be confused with sessile bivalves such as <a href="http://tidechaser.blogspot.sg/2012/12/pteriomorphia-bivalves-singapore.html#Ostreidae">oysters</a>, but the latter has a two-part shell.</li>
</ul>
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<b>15. <a href="http://tidechaser.blogspot.sg/2012/12/molluscs-mollusca-of-singapore.html">Molluscs (Phylum Mollusca)</a></b><br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5xWBt-TBiwHEiwPZsnTA5sjAUs2-xXRHebSaf-0tgUUmkcHpYubb5qO3_eBPSDrqdLFoI7Ewkr5suuDWbag47UrZUDN95KeqyqI6Bpet7TmsRno63O6ff6TVCDzf4lEP2nBWYRw/s1600/Mollusca.jpg"><img alt="Molluscs (Phylum Mollusca)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5xWBt-TBiwHEiwPZsnTA5sjAUs2-xXRHebSaf-0tgUUmkcHpYubb5qO3_eBPSDrqdLFoI7Ewkr5suuDWbag47UrZUDN95KeqyqI6Bpet7TmsRno63O6ff6TVCDzf4lEP2nBWYRw/s400/Mollusca.jpg" title="Molluscs (Phylum Mollusca)" width="400" /></a>
<br />
<br />
<b>Field characteristics:</b><br />
<ul style="text-align: left;">
<li>Soft-bodied, unsegmented and bilaterally symmetrical animals.</li>
<li>Most have a muscular foot.</li>
<li>Many have a special feeding structure called "radula", which is a tongue-like structure with rows of teeth on it.</li>
<li>Usually have a mantle with a cavity used for breathing and excretion.</li>
</ul>
<b>Examples:</b><br />
<ul style="text-align: left;">
<li><a href="http://tidechaser.blogspot.sg/2012/12/polyplacophora-chitons-of-singapore.html">Chitons</a></li>
<li><a href="http://tidechaser.blogspot.sg/2012/12/tusk-shells-scaphopoda-singapore.html">Tusk shells</a></li>
<li><a href="http://tidechaser.blogspot.sg/2012/12/cephalopoda-of-singapore.html">Cephalopods</a></li>
<li>Gastropods (<a href="http://tidechaser.blogspot.sg/2012/10/marine-snail-gastropoda-families.html">marine snails</a>, <a href="http://tidechaser.blogspot.sg/2012/05/marine-slugs-gastropoda-singapore.html">marine slugs</a> & <a href="http://tidechaser.blogspot.sg/2012/12/terrestrial-freshwater-snails-slugs.html">non-marine gastropods</a>)</li>
<li><a href="http://tidechaser.blogspot.sg/2012/12/marine-bivalves-of-singapore.html">Bivalves</a> </li>
</ul>
<b>May be confused with:</b><br />
<ul style="text-align: left;">
<li><a href="http://tidechaser.blogspot.sg/2013/06/barnacles-cirripedia-singapore.html">Barnacles</a> - Barnacles may be easily confused with <a href="http://tidechaser.blogspot.sg/2012/09/limpets-nacellidae-lottiidae.html">limpets</a>, which also have conical shells. They are, however, permanently fixed on hard structures, while limpets are motile. Also, the wall of the barnacle's shell has numerous holes and gaps internally (much like a sponge!), holding many pockets of air for heat insulation. Barnacles may also be confused with sessile bivalves such as <a href="http://tidechaser.blogspot.sg/2012/12/pteriomorphia-bivalves-singapore.html#Ostreidae">oysters</a>, but the latter have a two-part shell.</li>
<li><a href="http://tidechaser.blogspot.sg/2012/08/annelid-worms-annelida-singapore.html#Polynoidae">Scale worms</a> - Short-bodied annelid worms, such as scale worms, can be confused with chitons as both are usually found on rocky shores. Chitons, however, have an-eight-part shell on their back, while scale worms have numerous overlapping plated on their back.</li>
</ul>
<div style="text-align: right;">
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<b>16. <a href="http://tidechaser.blogspot.sg/2013/05/chordates-chordata-of-singapore.html">Chordates (Phylum Chordata)</a></b><br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiVc7Vocrj1FTWYnlZVs25uoekDbSYKxmvsH9Ym7XeICpnPKC6A3PaUj_zMKf6hnOaYr8U8_nGk7FIgry93YG0Eqi0Im-R8XinzfO3f1uCZGO9gv207mX_LglPQ8YujZNjDFJN4/s1600/chordata.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiVc7Vocrj1FTWYnlZVs25uoekDbSYKxmvsH9Ym7XeICpnPKC6A3PaUj_zMKf6hnOaYr8U8_nGk7FIgry93YG0Eqi0Im-R8XinzfO3f1uCZGO9gv207mX_LglPQ8YujZNjDFJN4/s400/chordata.jpg" width="400" /></a>
<br />
<br />
<b>Field characteristics:</b><br />
<ul style="text-align: left;">
<li>Bilaterally symmetrical animals with a nerve cord within a flexible rod-shaped structure called a notochord in their body.</li>
<li>They have pharyngeal slits - a series of openings that connect the inside of the throat to the outside, though in many chordates these are only present in the embryo.</li>
<li>They have a post-anal tail (an extended structure beyond the anal opening) that may only be present in the embryo for many species.</li>
</ul>
<b>Examples:</b><br />
<ul style="text-align: left;">
<li> <a href="http://tidechaser.blogspot.sg/2013/05/tunicates-ascidians-salps-singapore.html">Tunicates</a></li>
<li><a href="http://tidechaser.blogspot.sg/2013/05/cartilaginous-fishes-chondrichthyes.html">Cartilaginous fishes</a></li>
<li>Ray-finned fishes (<a href="http://tidechaser.blogspot.sg/2013/05/marine-ray-finned-fishes-of-singapore.html">marine</a> and <a href="http://tidechaser.blogspot.sg/2013/04/freshwater-fishes-actinopterygii.html">freshwater</a>)</li>
<li><a href="http://tidechaser.blogspot.sg/2013/03/frogs-amphibia-singapore.html">Amphibians</a></li>
<li><a href="http://tidechaser.blogspot.sg/2013/02/reptiles-reptilia-singapore.html">Reptiles</a></li>
<li><a href="http://tidechaser.blogspot.sg/2013/04/birds-aves-singapore.html">Birds</a> </li>
<li><a href="http://tidechaser.blogspot.sg/2012/09/mammals-mammalia-of-singapore.html">Mammals</a> </li>
</ul>
<b>May be confused with:</b><br />
<ul style="text-align: left;">
<li><a href="http://tidechaser.blogspot.sg/2013/03/sponges-porifera-singapore.html">Sponges</a> - Colonial tunicates are often mistaken for sponges. To differentiate them from the latter, take a closer look to spot the <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJJhbszv3Ag5Uwj8nPktCLevKxFbSFXZJ-uvlnymq_D6ruErclN0zxpBWoCqXn6WqLhM2ANImF_CTT7d-ty6GNwxWuuUsPhbKjMp5tN5Ie8BlCx2XKUyxrAEQj7e7Kk8eKBMrB/s1600/zooids.jpg">individual zooids</a>.</li>
<li><a href="http://tidechaser.blogspot.sg/2013/01/moss-animals-bryozoa-singapore.html">Bryozoans</a> - Colonial tunicates are sometimes mistaken for bryozoans. To differentiate them from the latter, take a closer look to spot the individual zooids, which lack the cell-like patterns.</li>
<li><a href="http://tidechaser.blogspot.com/2013/02/comb-jellies-ctenophora-singapore.html">Comb Jellies</a> - <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgJb1S7cqzmQxdrCAPfMy3ON1Qt9QcYMxMXtg-7oYjPPjIkUwsmmjyG3BxORBsFpkeyF9vfaz4p3z8ZthVFhaCglY6vzrhyBpn5n5xf8NuXmfBsDdkf-m2i0a06IkxKv4teQ1uM/s1600/salp.jpg">Salps (free-living tunicates)</a> are transparent and jelly-like, and are sometimes mistaken for comb jellies. They, however, lack both the comb rows and tentacles.</li>
</ul>
<div style="text-align: right;">
<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/05/chordates-chordata-of-singapore.html"><b>>> more</b></a></span></div>
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<b>References</b><br />
<ul style="text-align: left;">
<li>Burnie, D. 2001. <i>Animal</i>. London: Dorling Kindersley. 624 pp.</li>
<li>Ng, P. K .L., R. T. Corlett & H.T.W. Tan (eds.). 2011. <i>Singapore biodiversity: An encyclopedia of the natural environment and sustainable development</i>. Singapore: Editions Didier Millet. 552 pp.</li>
<li>Mayer, G. 2006. <i>Onychophora Website</i>. Retrieved Feb 4, 2013, from http://www.onychophora.com. </li>
<li>Ruppert, E.E. and R.D. Barnes. 1991. <i>Invertebrate Zoology (International Edition)</i>. Saunders College Publishing. U.S.A. 1056 pp. </li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
</div>
Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com1tag:blogger.com,1999:blog-9797239.post-20130559661885477922013-07-26T21:44:00.000+08:002013-07-27T21:32:46.515+08:00Photographic Guide to the Flora & Fauna of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
<!--- Some of the students and public participants of my nature walks had previously told me that they hope I can put up some photographic identification guides on my blog. Not only do these guides help the students with their school work, they also make it easier for other participants to check on the identity of the wildlife they see on their own nature walks. As such, since end of last year, I decided to put up a series of identification guides to some of the flora and fauna of Singapore.<br />
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There may not be a lot of information here now, but I guess this series of identification guides will always be a work-in-progress. When I have the time and when I see and learn new things, I will put up more identification guides or additional details existing content. I am hoping to eventually put up information on both marine and terrestrial organisms, so do visit this page again for updates! :)<br />
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A quick look at some of the organisms that can be found in Singapore! Will update with more organisms and information as and when I have the time! :)<br />
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<b>A) FAUNA OF SINGAPORE</b><br />
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Here are some of Singapore's fauna that I have seen and photographed so far...<br />
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<td colspan="2"><b>1. <a href="http://tidechaser.blogspot.sg/2013/03/sponges-porifera-singapore.html">Sponges (Phylum Porifera)</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.sg/2013/03/sponges-porifera-singapore.html" style="clear: left; float: left; margin-bottom: 0em; margin-right: 1em;"><img border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXZSs4It2u73lkwFNQt_SaZA4DjC4y2GNHPgYjecBXCVCK-W2G-ecOUtj0YKCmBLFL9oCndSaNZ8Qpw99-qMtLpd0to9YrXx0mVDRbcU2IexrJ6SHFnpYiEgjD__MvF97IWnU-/s200/porifera.jpg" width="200" /></a>
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<br /></td><td valign="top">Sponges are very simple multicellular animals with no true tissue and organ. They also have no body symmetry, and are just congregation of several types of cells which form an organised structure with numerous pores and channels for the circulation of water.<br />
<div style="text-align: right;">
<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/03/sponges-porifera-singapore.html"><b>>> more</b></a></span></div>
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<td colspan="2"><b>2. <a href="http://tidechaser.blogspot.com/2013/02/comb-jellies-ctenophora-singapore.html">Comb Jellies (Phylum Ctenophora)</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.com/2013/02/comb-jellies-ctenophora-singapore.html" style="clear: left; float: left; margin-bottom: 0em; margin-right: 1em;"><img alt="Comb jelly (phylum Ctenophora)" border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQJ40jI7tP_x8hff61pWU6xT4W8-UVWLJBd0oSzz2p95diqB4cc8Vv79IVjwNKqmrXWIU9qwxntg_u7wS_gYHRkzUgmwFxkdjAYJVBAIgNgQnE_tj3CIhb9_EN0PTxt_u0IjIp/s200/Comb-Jelly.jpg" title="Comb jelly (phylum Ctenophora)" width="200" /></a></td>
<td valign="top">Comb jellies are mostly free-swimming organisms that appear like jellyfish with eight strips running down the length of their bodies. Others creep over the substrate, resembling flatworms. Many comb jellies possess a pair of tentacles fringed with smaller tentacles. <br />
<div style="text-align: right;">
<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.com/2013/02/comb-jellies-ctenophora-singapore.html"><b>>> more</b></a></span></div>
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<td colspan="2"><b>3. <a href="http://tidechaser.blogspot.sg/2013/01/cnidarians-cnidaria-singapore.html">Cnidarians (Phylum Cnidaria)</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.sg/2013/01/cnidarians-cnidaria-singapore.html" style="clear: left; float: left; margin-bottom: 0em; margin-right: 1em;"><img border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglFzPoa00uTDV7IpehNE_SonQ_IqomWJMrAyGfsMqvmAn0HBwhyphenhyphen0Oo4EhYU7jSbX6y9XsgbUnfM7H1KjBZgA1RH2ZtEa-dFeEJkysMdqcFPxU6rW10VOxmEgRpzv2mLPNLLz_-/s200/cnidarians.jpg" width="200" /></a></td>
<td valign="top">Cnidarians are radially symmetrical animals with tentacles that possess explosive, harpoon-like cells (cnidocytes). Examples include <a href="http://tidechaser.blogspot.sg/2013/01/sea-anemones-actiniaria-singapore.html">sea anemones</a>, <a href="http://tidechaser.blogspot.sg/2013/01/tube-anemones-ceriantharia-singapore.html">tube anemones</a>, <a href="http://tidechaser.blogspot.sg/2013/01/mushroom-anemones-corallimorphs.html">corallimorphs</a>, <a href="http://tidechaser.blogspot.sg/2012/12/hard-corals-scleractinia-singapore.html">hard corals</a>, <a href="http://tidechaser.blogspot.sg/2013/01/zoanthids-zoantharia-of-singapore.html">zoanthids</a>, <a href="http://tidechaser.blogspot.sg/2012/12/soft-corals-alcyonacea-singapore.html">soft corals</a>, <a href="http://tidechaser.blogspot.sg/2013/01/blue-coral-heliopora-coerulea-singapore.html">blue corals</a>, <a href="http://tidechaser.blogspot.sg/2013/01/sea-pens-pennatulacea-singapore.html">sea pens</a>, <a href="http://tidechaser.blogspot.sg/2013/01/hydroids-hydrozoa-singapore.html">hydroids</a>, and <a href="http://tidechaser.blogspot.sg/2013/01/jellyfish-scyphozoa-singapore.html">jellyfish</a>.<br />
<div style="text-align: right;">
<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/01/cnidarians-cnidaria-singapore.html"><b>>> more</b></a></span></div>
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<td colspan="2"><b>4. <a href="http://tidechaser.blogspot.sg/2012/08/horseshoe-worm-phoronida-singapore.html">Horseshoe Worm (Phylum Phoronida)</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.sg/2012/08/horseshoe-worm-phoronida-singapore.html" style="clear: left; float: left; margin-bottom: 0em; margin-right: 1em;"><img border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEids2F9jgMSZ3glu421DwAVe68hTcPdWXbYwvKFjuFhGzWXEr7CXTsQlhZLAUvLq9VxFlq-WPMqAwZhtNUUtXIjOPIC4WEYTjk-mzX-yQw0_zPNj35PNRK2XZESaW_U0vpfHlLi4g/s200/Phoronis-australis.jpg" width="200" /></a>
</td><td valign="top">Horseshoe worms are marine worms living in tubes and have a crown of tentacles arranged in a somewhat horseshoe shape if viewed from the top. One species, the Black Horseshoe Worm (<i>Phoronis australis</i>) which lives with tube anemones, can be seen in Singapore.<br />
<div style="text-align: right;">
<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2012/08/horseshoe-worm-phoronida-singapore.html"><b>>> more</b></a></span></div>
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<td colspan="2"><b>5. <a href="http://tidechaser.blogspot.sg/2013/01/moss-animals-bryozoa-singapore.html">Moss Animals (Phylum Bryozoa)</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.sg/2013/01/moss-animals-bryozoa-singapore.html" style="clear: left; float: left; margin-bottom: 0em; margin-right: 1em;"><img border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYG8fbK7fs8lvDFRVx1Iloyk0E3HKfWT4L0FVgI6qJw1N8NhBzoiIjExlufBaNYEuwkFJkyDTjHhO7hK8o0ke3nNTF9UkxPcPX0PlfH-4rVgnx5TZcuwFtS-gO4Ff_BD6Vo4sA/s200/Bryozoa.jpg" width="200" /></a>
</td><td valign="top">Bryozoans are tiny organisms that mostly live in colonies (except for one solitary species). Each individual bryozoan animal has a lophophore, which is a crown of tentacles for filter feeding, and lives in a chitinous or calcareous chamber-like exoskeleton (or zooecium).<br />
<div style="text-align: right;">
<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/01/moss-animals-bryozoa-singapore.html"><b>>> more</b></a></span></div>
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<td colspan="2"><b>6. <a href="http://tidechaser.blogspot.sg/2013/02/lamp-shells-brachiopoda-singapore.html">Lamp Shells (Phylum Brachiopoda)</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.sg/2013/02/lamp-shells-brachiopoda-singapore.html" style="clear: left; float: left; margin-bottom: 0em; margin-right: 1em;"><img alt="Lamp shell (Lingula sp.)" border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiSXqDZoregddZPpIMHGO_Sbdf5oKCdW93nyE4eqXaRClFbrlHqo85aeBr3gTHfAFnjCIXtMY11o3TLbgBecHG4hQ0rDzVpLCHyONEgJlT0yxG91OkGGpwPVwv_HVWK-gpJxLFa/s200/Brachiopod.jpg" title="Lamp shell (Lingula sp.)" width="200" /></a>
</td><td valign="top">Brachiopods, or lamp shells, are solitary, clam-like animals with a two-part shell. Unlike a clam which has a left valve and a right valve (based on how the valves are oriented to the body), a lamp shell has a dorsal (or "upper") valve and a ventral (or "lower") valve.<br />
<div style="text-align: right;">
<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/02/lamp-shells-brachiopoda-singapore.html"><b>>> more</b></a></span></div>
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<td colspan="2"><b>7. <a href="http://tidechaser.blogspot.sg/2013/07/acoels-acoelomorpha-flatworms-singapore.html">Acoel Worms (Phylum Acoelomorpha)</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.sg/2013/07/acoels-acoelomorpha-flatworms-singapore.html" style="clear: left; float: left; margin-bottom: 0em; margin-right: 1em;"><img alt="Waminoa Acoel Worms (Waminoa sp.)" border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjf7J15YrDisigYylNUOxqiccj1RpOdXTacBMkNssWFiEm_L0AqicUU8dbpoFXGyg-y11mNajHzeRYRLs003W2fvKN6Ur_GXrZJtBIFw-E_T7YJDKnsN0dqTb7DklwjXW0Nwvk8vA/s200/Waminoa.jpg" title="Acoel Worms (Phylum Acoelomorpha)" width="200" /></a>
</td><td valign="top">The acoels are flat, bilaterally symmetric, soft-bodied unsegmented worms typically found in the marine environment. They do not have a gut cavity, and have a distinctive balance sensory receptor (made up of a large cell bearing a calcareous body) at the front end.<br />
<div style="text-align: right;">
<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/07/acoels-acoelomorpha-flatworms-singapore.html"><b>>> more</b></a></span></div>
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<td colspan="2"><b>8. <a href="http://tidechaser.blogspot.sg/2012/04/echinoderms-of-singapore.html">Echinoderms (Phylum Echinodermata)</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.sg/2012/04/echinoderms-of-singapore.html" style="clear: left; float: left; margin-bottom: 0em; margin-right: 1em;"><img border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhHiyKoWiwYz_0DnOFJ6V90OWnwY6RetJmk_s7gT-0XdzElcKZlW6xwtXuRsb5hmYPqDJ4tRZyHjdMYcWkmOb2rObzs3EuqFpCvDJ7xiRuR0iGmEW4ZDyW-035PEQL_CREbWI3RtQ/s200/echinoderms.jpg" width="200" /></a></td>
<td valign="top">Echinoderms are marine animals with penta-radial symmetry, i.e. each echinoderm can be divided into 5 equal parts, at least in some stage of life. They include the various species of <a href="http://tidechaser.blogspot.sg/2012/03/sea-stars-class-asteroidea-of-singapore.html">sea stars</a>, <a href="http://tidechaser.blogspot.sg/2012/03/feather-star-crinoidea-of-singapore.html">feather stars</a>, <a href="http://tidechaser.blogspot.sg/2012/03/brittle-stars-ophiuroidea-of-singapore.html">brittle stars</a>, <a href="http://tidechaser.blogspot.sg/2012/04/sea-cucumbers-holothuroidea-of.html">sea cucumbers</a>, <a href="http://tidechaser.blogspot.sg/2012/03/sea-urchins-echinoidea-of-singapore.html">sea urchins and sand dollars</a>.<br />
<div style="text-align: right;">
<a href="http://tidechaser.blogspot.sg/2012/04/echinoderms-of-singapore.html"><span style="font-size: x-small;"><b>>> more</b></span></a></div>
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<td colspan="2"><b>9. <a href="http://tidechaser.blogspot.sg/2013/02/acorn-worms-hemichordata-singapore.html">Hemichordates (Phylum Hemichordata)</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.sg/2013/02/acorn-worms-hemichordata-singapore.html" style="clear: left; float: left; margin-bottom: 0em; margin-right: 1em;"><img alt="Acorn Worm Cast" border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjsiAWB22YP1vtxnRlBqKUnboND9SqmFnKi5Z-TlB_kr6RuGJm2LySzp1kmXBJwqOZ5cAQ8CE5gpnoqJmjjrq8aPCyltsr3k5T7sK4WNa2Yre0PLbf48WO6LyeFISagQLlBTeH3/s200/Acorn-worm.jpg" title="Acorn Worm Cast" width="200" /></a></td>
<td valign="top">Hemichordates are worm-like animals characterised by a three-part body - the front end, followed by a collar, and a posterior trunk. There is a flexible, hollow tube (the stomochord) in the collar region, somewhat resembling the notochord found in chordates.<br />
<div style="text-align: right;">
<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/02/acorn-worms-hemichordata-singapore.html"><b>>> more</b></a></span></div>
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<td colspan="2"><b>10. <a href="http://tidechaser.blogspot.sg/2012/08/annelid-worms-annelida-singapore.html">Annelid Worms (Phylum Annelida)</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.sg/2012/08/annelid-worms-annelida-singapore.html" style="clear: left; float: left; margin-bottom: 0em; margin-right: 1em;"><img border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg-kopDN4Ts7YDLaUKV24XhKzKCA-Fd-o-rBoHoFXP6-6tykoQfd5du5Ow7Gw7JT6dQ4UYm-k0jLmoDP0IBiLsSrniQxIENoLKSMcObZ0kjAbF_u3C3PsNYkC2oSFTlxWanbz_gTw/s200/Annelida.jpg" width="200" /></a>
</td><td valign="top">Annelids are bilaterally symmetrical worms which may or may not be segmented. The segmented annelids will have a body comprising identical segments. Recent studies have shown that unsegmented worms such as the spoon worms and peanut worms are also annelids.<br />
<div style="text-align: right;">
<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2012/08/annelid-worms-annelida-singapore.html"><b>>> mor<span style="font-size: x-small;">e</span> </b></a></span></div>
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<td colspan="2"><b>11. <a href="http://tidechaser.blogspot.sg/2012/08/ribbon-worms-nemertea-singapore.html">Ribbon Worms (Phylum Nemertea)</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.sg/2012/08/ribbon-worms-nemertea-singapore.html" style="clear: left; float: left; margin-bottom: 0em; margin-right: 1em;"><img border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjpGoQ6gPYTeqP05YA7qc_IjR48bOdKfW-8q42K9yiT5Y1E7n3hhMHI8NFvQbV_fJvxHonkaZJ1P4_yrt6DrLbwWrcuIpvtKCgjO_Epa7JSmwFHJ5Focjc0QkpBUqXAJOlriJx4lQ/s200/ribbonworms.jpg" width="200" /></a>
</td><td valign="top">Ribbon worms are soft-bodied, bilaterally symmetrical animals that are mostly long, thin and flat (like a ribbon). Some species, however, have short and wide bodies. They have an eversible proboscis which can shoot out just above the mouth to capture/retrieve their food.<br />
<div style="text-align: right;">
<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2012/08/ribbon-worms-nemertea-singapore.html"><b>>> more</b></a></span></div>
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<td colspan="2"><b>12. <a href="http://tidechaser.blogspot.sg/2012/08/flatworms-platyhelminthes-singapore.html">Flatworms (Phylum Platyhelminthes)</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.sg/2012/08/flatworms-platyhelminthes-singapore.html" style="clear: left; float: left; margin-bottom: 0em; margin-right: 1em;"><img border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhS2MjYBecqeQSBdbywbZsnhANVenebY68j0mdPigqQkC636MPwRL_W14qUmzroI7MJTuO-E3U057nSEEALkIxgjF37JOmXTEMz7FHpVTH7TlpLUIGmg4nf_eWtTlaSCXSoJHTeKA/s200/flatworm.jpg" width="200" /></a></td>
<td valign="top">Flatworms are unsegmented worms with soft and bilaterally symmetrical bodies. They are mostly very flat, and hence the common name "flatworm". While many flatworms are parasites of other animals, we can still see many pretty free-living flatworms on our shores and forests.<br />
<div style="text-align: right;">
<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2012/08/flatworms-platyhelminthes-singapore.html"><b>>> more</b></a></span></div>
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<td colspan="2"><b>13. <a href="http://tidechaser.blogspot.sg/2013/02/velvet-worm-onychophora-singapore.html">Velvet Worms (Phylum Onychophora)</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.sg/2013/02/velvet-worm-onychophora-singapore.html" style="clear: left; float: left; margin-bottom: 0em; margin-right: 1em;"><img alt="Velvet Worms (Phylum Onychophora)" border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9xXvscu4HuOH2JURyQVZ2ZEWyGl7jN7sWc1B0yZDstJLHj_XDB4Jywl7SGnqvoht0oNx1wgQDJtaZtQtRXWz5igwLbU_Qz3PMxtbzbodtqSeYF4dwLHjjwzCmwqp71avVIYge/s200/Onychophora.jpg" title="Velvet Worms (Phylum Onychophora)" width="200" /></a></td>
<td valign="top">Velvet worms are segmented, centipede-like organisms with numerous pairs of walking legs. Each leg has a pair of claws. They lack a rigid exoskeleton, and instead, the body cavity is filled with a fluid to make them firm. They hunt small invertebrates with a glue-like slime.<br />
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<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/02/velvet-worm-onychophora-singapore.html"><b>>> more</b></a></span></div>
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<td colspan="2"><b>14. <a href="http://tidechaser.blogspot.sg/2013/06/arthropods-arthropoda-singapore.html">Arthropods (Phylum Arthropoda)</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.sg/2013/06/arthropods-arthropoda-singapore.html" style="clear: left; float: left; margin-bottom: 0em; margin-right: 1em;"><img border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhl_rgjKrSER2glwkw6UbFbPVanNlOJ4qHnAAx1P2t93kT_YfrRoHpIgo6dAK-2gHEYfxjuIMU2I6BcaWW03QQNOVPW32jrvlIU2LRujqWtnxnA5X295I7taeyQBv_i9vkSOyeHpw/s200/Arthropoda.jpg" width="200" /></a>
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<td valign="top">Arthropods have segmented bodies, jointed limbs, and external skeletons. They need to moult as they develop. Examples include <a href="http://tidechaser.blogspot.sg/2013/06/millipedes-diplopoda-singapore.html">millipedes</a>, <a href="http://tidechaser.blogspot.sg/2013/06/centipedes-chilopoda-singapore.html">centipedes</a>, <a href="http://tidechaser.blogspot.sg/2013/06/arthropods-arthropoda-singapore.html#Symphyla">symphylans</a>, <a href="http://tidechaser.blogspot.sg/2013/06/horseshoe-crabs-merostomata-limulidae.html">horseshoe crabs</a>, <a href="http://tidechaser.blogspot.sg/2013/06/spiders-scorpions-arachnida-singapore.html">arachnids</a>, <a href="http://tidechaser.blogspot.sg/2013/06/arthropods-arthropoda-singapore.html#Pycnogonida">sea spiders</a>, <a href="http://tidechaser.blogspot.sg/2013/06/insects-insecta-singapore.html">insects</a>, <a href="http://tidechaser.blogspot.sg/2013/06/arthropods-arthropoda-singapore.html#Entognatha">springtails</a>, <a href="http://tidechaser.blogspot.sg/2013/06/malacostracans-malacostraca-singapore.html">malacostracans</a> and <a href="http://tidechaser.blogspot.sg/2013/06/barnacles-cirripedia-singapore.html">barnacles</a>.<br />
<div style="text-align: right;">
<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/06/arthropods-arthropoda-singapore.html"><b>>> more</b></a></span></div>
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<td colspan="2"><b>15. <a href="http://tidechaser.blogspot.sg/2012/12/molluscs-mollusca-of-singapore.html">Molluscs (Phylum Mollusca)</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.sg/2012/12/molluscs-mollusca-of-singapore.html" style="clear: left; float: left; margin-bottom: 0em; margin-right: 1em;"><img border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjzyrTjmaYZby3T5q14kJeTx4DlwDcENvA7v3UOZ9DO_p-yE3QfnE6_1yKZN_3R8koHCCjTbDoBV95rGLxsU8pzNEwvDWn-ib3xrFG7Sg3Ja5NjOMNk3ZRtKdROzdZtlVtqJkx-3w/s200/mollusca.jpg" width="200" /></a>
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<td valign="top">Molluscs are soft-bodied animals. Most species have shells (can be very reduced), a mantle, a muscular foot and a radula. Examples include <a href="http://tidechaser.blogspot.sg/2012/12/polyplacophora-chitons-of-singapore.html">chitons</a>, <a href="http://tidechaser.blogspot.sg/2012/12/tusk-shells-scaphopoda-singapore.html">tusk shells</a>, <a href="http://tidechaser.blogspot.sg/2012/12/cephalopoda-of-singapore.html">cephalopods</a>, gastropods (<a href="http://tidechaser.blogspot.sg/2012/10/marine-snail-gastropoda-families.html">marine snails</a>, <a href="http://tidechaser.blogspot.sg/2012/05/marine-slugs-gastropoda-singapore.html">marine slugs</a>, <a href="http://tidechaser.blogspot.sg/2012/12/terrestrial-freshwater-snails-slugs.html">non marine gastropods</a>) and <a href="http://tidechaser.blogspot.sg/2012/12/marine-bivalves-of-singapore.html">bivalves</a>.<br />
<div style="text-align: right;">
<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2012/12/molluscs-mollusca-of-singapore.html"><b>>> more</b></a></span></div>
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<td colspan="2"><b>16. <a href="http://tidechaser.blogspot.sg/2013/05/chordates-chordata-of-singapore.html">Chordates (Phylum Chordata)</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.sg/2013/05/chordates-chordata-of-singapore.html" style="clear: left; float: left; margin-bottom: 0em; margin-right: 1em;"><img border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiVc7Vocrj1FTWYnlZVs25uoekDbSYKxmvsH9Ym7XeICpnPKC6A3PaUj_zMKf6hnOaYr8U8_nGk7FIgry93YG0Eqi0Im-R8XinzfO3f1uCZGO9gv207mX_LglPQ8YujZNjDFJN4/s200/chordata.jpg" width="200" /></a>
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<br /></td><td valign="top">Chordates are characterised by having a nerve cord within a flexible rod-shaped structure called a notochord in their body. Examples include the <a href="http://tidechaser.blogspot.sg/2013/05/tunicates-ascidians-salps-singapore.html">tunicates</a>, <a href="http://tidechaser.blogspot.sg/2013/05/cartilaginous-fishes-chondrichthyes.html">cartilaginous fishes</a>, ray-finned fishes (<a href="http://tidechaser.blogspot.sg/2013/05/marine-ray-finned-fishes-of-singapore.html">marine</a> and <a href="http://tidechaser.blogspot.sg/2013/04/freshwater-fishes-actinopterygii.html">freshwater</a>), <a href="http://tidechaser.blogspot.sg/2013/03/frogs-amphibia-singapore.html">amphibians</a>, <a href="http://tidechaser.blogspot.sg/2013/02/reptiles-reptilia-singapore.html">reptiles</a>, <a href="http://tidechaser.blogspot.sg/2013/04/birds-aves-singapore.html">birds</a> and <a href="http://tidechaser.blogspot.sg/2012/09/mammals-mammalia-of-singapore.html">mammals</a>.<br />
<div style="text-align: right;">
<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/05/chordates-chordata-of-singapore.html"><b>>> more</b></a></span></div>
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<b>B) FLORA OF SINGAPORE</b><br />
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Kindly note the plant guides below can only be used in Singapore, as the same species may have different morphological features in other places.<br />
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<td colspan="2" valign="top"><b>1. <a href="http://tidechaser.blogspot.sg/2011/11/identifying-true-mangrove-plants-of.html">True Mangrove Plants</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.sg/2011/11/identifying-true-mangrove-plants-of.html" imageanchor="1" style="clear: left; float: left; margin-bottom: 0em; margin-right: 1em; text-align: center;"><img border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrikE1ikv5Bh9X-MaFEuS0teSDAQ1nuTMcszbV48VpZhWsPKJeT8iQBYojkQFN3UgkTgNWvkwOaYX-Du6N94mMTGG6Vtc8NtEBTfsRF9MKI9D3HrWHrwLROLYtfNrraXSxyG3S5Q/s200/Mangroves.jpg" width="200" /></a></td>
<td valign="top">True mangrove species refer to those that grow only in mangrove environment. They are adapted to survive in saline, waterlogged and anaerobic conditions. Based on Tomlinson’s list, Singapore has 30 true mangrove species, and here's an ID key that I have developed to identify them.<br />
<div style="text-align: right;">
<span style="font-size: x-small;"><b><a href="http://tidechaser.blogspot.sg/2011/11/identifying-true-mangrove-plants-of.html">>> more</a></b></span></div>
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<td colspan="2"><b>2. <a href="http://tidechaser.blogspot.com/2012/07/coastal-shrubs-trees-simple-leaves.html">Coastal Shrubs & Trees (with Simple Leaves)</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.com/2012/07/coastal-shrubs-trees-simple-leaves.html" imageanchor="1" style="clear: left; float: left; font-weight: bold; margin-bottom: 0em; margin-right: 1em; text-align: center;"><img border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhs2pRtPrYNhrFRaTEzONq1jSQuizqnm_Q26N_kGxksAOcKkgRw0H49E9LmvRoT1m5DjcJWX9FmCk7J48b-YNNOd5XYFo86T5vxR-4EL-tjZfEfqPcSzBOPVavq44KvYFCcP8wz1w/s200/Simple-Leaves.jpg" width="200" /></a></td>
<td valign="top">These plants have simple leaves, i.e. leaves that are not divided into leaflets. They may have <a href="http://tidechaser.blogspot.sg/2012/07/coastal-shrubs-trees-simple-leaves.html#C">opposite leaves</a>, <a href="http://tidechaser.blogspot.sg/2012/07/coastal-shrubs-trees-simple-leaves.html#D">alternate leaves</a>, or spirally arranged leaves (especially in <a href="http://tidechaser.blogspot.sg/2012/07/coastal-shrubs-trees-simple-leaves.html#A">monocot plants</a>). Sometimes, the <a href="http://tidechaser.blogspot.sg/2012/07/coastal-shrubs-trees-simple-leaves.html#B">leaves are so reduced</a> that it is hard to determine the arrangement.<br />
<div style="text-align: right;">
<a href="http://tidechaser.blogspot.com/2012/07/coastal-shrubs-trees-simple-leaves.html"><b><span style="font-size: x-small;">>>more</span></b></a></div>
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<td colspan="2"><b>3. <a href="http://tidechaser.blogspot.com/2012/07/coastal-shrubs-trees-compound-leaves.html">Coastal Shrubs & Trees (with Compound Leaves)</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.com/2012/07/coastal-shrubs-trees-compound-leaves.html" style="clear: left; float: left; font-weight: bold; margin-bottom: 0em; margin-right: 1em; text-align: center;"><img border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiCEqWcSfRxiIube-Vqns49RyPhs6MnWqV3KpXFfQAwzxhMVkXn6hQr491Sp23JEFTMv4EQGq9C_zb7abRO0za1sl2cB8f2kFthOZnUXW5v_rZ_spy6iG5XIqcsN1ycv_JB0kLSvg/s200/Compound-leaves.jpg" width="200" /></a></td>
<td valign="top">These plants have each of their leaves fully subdivided into leaflets. Compound leaves can be differentiated from simple leaves by identifying where the petiole (the leaf stalk attaching the leaf to the stem) occurs. A new compound leaf also occurs as one with many small new leaflets.<br />
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<b><a href="http://tidechaser.blogspot.com/2012/07/coastal-shrubs-trees-compound-leaves.html"><b><span style="font-size: x-small;">>> more</span></b></a></b></div>
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<td colspan="2"><b style="font-weight: bold;">4. <a href="http://tidechaser.blogspot.com/2012/04/mangrove-climbers-creepers-singapore.html">Coastal Creepers & Climbers</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.com/2012/04/mangrove-climbers-creepers-singapore.html" style="clear: left; float: left; font-weight: bold; margin-bottom: 0em; margin-right: 1em;"><img border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwTg058EX6MT0ljSjLteBmtc8jzO4t2gmxa3aJtoJONMFhCSWCL2jhZtJ776xPupNHvZ-0aEsyPgb8XToFGW-k5KelK1V025Q-Rsx6E8aMj1U510RjQTni0JQtvxx40Sc421xxzg/s200/CreepersClimbers.jpg" width="200" /></a></td>
<td valign="top">The creepers and climbers featured here refer to plants with long and narrow stem that spread over the ground and lower structures (i.e. creepers) and those that climbing onto taller structures and trees (i.e. climbers), but exclude the grasses and grass-like plants. <br />
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<b><a href="http://tidechaser.blogspot.sg/2012/04/mangrove-climbers-creepers-singapore.html"><b><span style="font-size: x-small;">>> more</span></b></a></b></div>
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<td colspan="2"><b>5. <a href="http://tidechaser.blogspot.com/2012/07/coastal-epiphytes-mistletoes-herbs.html">Coastal Epiphytes, Ferns & Ground-dwelling Herbs</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.com/2012/07/coastal-epiphytes-mistletoes-herbs.html" imageanchor="1" style="clear: left; float: left; font-weight: bold; margin-bottom: 0em; margin-right: 1em; text-align: center;"><img border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgiIJjl2QiNWmTJEuW50PW2sidPn9r3NrHg9Zrcz4cPFgPYhZIyA5Yto4TE5HR23iaalYgX5qDkZXcxU4g7PqokDLqBYuaQwtwwpPdzBGzum9quT5A6OWahyphenhyphenwpZ4VO616gWKm1P_g/s200/herbs.jpg" width="200" /></a></td>
<td valign="top">An epiphyte is a plant that grows upon another plant. True epiphytes do not derive nutrients from the host plant, unlike parasitic epiphytes. Ferns are vascular plants which do not produce seeds but reproduce via spores. Herbs are flowering plant with no persistent woody stems.<br />
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<a href="http://tidechaser.blogspot.com/2012/07/coastal-epiphytes-mistletoes-herbs.html"><b><span style="font-size: x-small;">>> more</span></b></a></div>
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<td colspan="2"><b>6. <a href="http://tidechaser.blogspot.sg/2012/11/mistletoes-of-singapore.html">Mistletoes of Singapore</a></b></td>
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<td valign="top"><a href="http://tidechaser.blogspot.sg/2012/11/mistletoes-of-singapore.html" style="clear: left; float: left; margin-bottom: 0em; margin-right: 1em;"><img alt="Mistletoes" border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhPngWkuuWdk5BjFU15Hd6KdjoGdsgljMDo7kQ4_KshttCx5O8pOxQzTfF82PyKVE5OjQMG_CtebxHcG8SyU85yoFSfENKUvoC_J6VcuxHKxODrlXSbjnFN3axH1J3Ej5uov-V5Nw/s200/Mistletoes.jpg" title="Mistletoes" width="200" /></a></td>
<td valign="top">Mistletoes are obligate hemiparasitic shrubs from the order Santalales. They have modified roots called "haustoria" which penetrate into the host plants' tissues to draw water and non-organic nutrients, but are able to photosynthesize to produce their own sugar.<br />
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<a href="http://tidechaser.blogspot.sg/2012/11/mistletoes-of-singapore.html"><b><span style="font-size: x-small;">>> more</span></b></a></div>
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Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com8tag:blogger.com,1999:blog-9797239.post-16844511872764279252013-07-26T21:42:00.001+08:002013-07-27T21:01:22.190+08:00Acoel Worms (Phylum Acoelomorpha) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
The acoels, or acoel worms (phylum Acoelomorpha), are flat, bilaterally symmetric, soft-bodied unsegmented worms typically found in the marine environment. <br />
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They do not have a gut cavity, and hence the name "acoel", which means "no cavity" in Latin. Depending on the species, the mouth can be anywhere on the body, though for most species it is located in the middle of the underside. The ingested food is encompassed and digested by special digestive tissues. Some acoels feed on algae and detritus (i.e. tiny decaying organic particles), while others form symbiotic relationships with <a href="http://tidechaser.blogspot.sg/2013/01/cnidarians-cnidaria-singapore.html">cnidarians</a> and feed on any tiny organic matter trapped in the mucus produced by the latter, or harbour symbiotic algae which are able to photosynthesise and share food with the host acoels.<br />
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Acoels do not have excretory organs, and waste is usually excreted by some of the cells.<br />
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As they are mostly very flat, they were previously classified as <a href="http://tidechaser.blogspot.sg/2012/08/flatworms-platyhelminthes-singapore.html">flatworms (phylum Platyhelminthes)</a>. Studies have shown that they are more primitive than flatworms though, and can be distinguished from the latter by having a distinctive balance sensory receptor (or statocyst) at the front end. This statocyst is made up of a large cell bearing one calcareous body (or statolith) within a capsule formed by two cells. Sometimes, those that have been reproduced asexually may not have the statocyst though.<br />
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Despite the fact that they are very simple animals, acoels possess a very simple brain which may be shaped like a ring, a barrel or a two-lobed structure.<br />
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Acoels can reproduce sexually or asexually. They are simultaneous hermaphrodites (with both male and female reproductive parts), and in sexual reproduction, some may exchange sperms, while in other cases one may perform the role of a male while another the female. Some species have a specific opening for the female reproductive part, and for these species, the male reproductive part tends to be soft and muscular to be inserted into the female opening for sperm transffer. Other species may have female reproductive parts scattered around the body, and possess needle-like male reproductive parts to penetrate the skin of another acoel to inject the sperm. The fertilised eggs will then be laid. In asexual reproduction, they may split into two, or grow a new acoel from the body (this process is known as budding), which eventually detaches and develops into a separate animal.<br />
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Like many other simple animals, acoels are able to regenerate lost body parts.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjf7J15YrDisigYylNUOxqiccj1RpOdXTacBMkNssWFiEm_L0AqicUU8dbpoFXGyg-y11mNajHzeRYRLs003W2fvKN6Ur_GXrZJtBIFw-E_T7YJDKnsN0dqTb7DklwjXW0Nwvk8vA/s1600/Waminoa.jpg"><img alt="Waminoa Acoel Worms (Waminoa sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjf7J15YrDisigYylNUOxqiccj1RpOdXTacBMkNssWFiEm_L0AqicUU8dbpoFXGyg-y11mNajHzeRYRLs003W2fvKN6Ur_GXrZJtBIFw-E_T7YJDKnsN0dqTb7DklwjXW0Nwvk8vA/s400/Waminoa.jpg" title="Waminoa Acoel Worms (Waminoa sp.)" width="400" /></a><br />
The only acoel I have personally seen in Singapore are those that infest cnidarians. They are tentatively identified as <b>Waminoa Acoels (<i>Waminoa </i>sp.)</b>. They are typically less than 0.5cm long.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXj1gM2tNAted2caiSytqw23vHV3Gjh_BjTlQpgdUMUmM1qyLK1RzBgtfOO2uUJ8p1CYsf8x73NUDWR_zy9pt9GapymK3uXsJCy0xEOfYtK1B-7hnXgi0veMuvXsKOI1WI1QAEKw/s1600/Waminoa2.jpg"><img alt="Waminoa Acoel Worms (Waminoa sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXj1gM2tNAted2caiSytqw23vHV3Gjh_BjTlQpgdUMUmM1qyLK1RzBgtfOO2uUJ8p1CYsf8x73NUDWR_zy9pt9GapymK3uXsJCy0xEOfYtK1B-7hnXgi0veMuvXsKOI1WI1QAEKw/s400/Waminoa2.jpg" title="Waminoa Acoel Worms (Waminoa sp.)" width="400" /></a><br />
Waminoa Acoels are known to harbour symbiotic algae which photosynthesise and contribute to the host acoel's nutritional needs. Their brownish coloration is probably due to the colour of the symbiotic algae. It is suggested that Waminoa Acoels feed on the organic particles trapped in the mucus produced by the host cnidarian to supplement their nutritional needs as well.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjeGCK87TVI6WFBnyLPJYYo9x-rcfrpti2mzdlMn1cu8CWKtLFVApPKkX8zfE1iXnokRC0zUr93z35n9aAYkqRkPUGIL7sHBIZKB_wmO_h2iHxbG5imuoi-HBHUpsBBvcaAHTZsyQ/s1600/Acoel2.jpg"><img alt="Waminoa Acoel Worms (Waminoa sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjeGCK87TVI6WFBnyLPJYYo9x-rcfrpti2mzdlMn1cu8CWKtLFVApPKkX8zfE1iXnokRC0zUr93z35n9aAYkqRkPUGIL7sHBIZKB_wmO_h2iHxbG5imuoi-HBHUpsBBvcaAHTZsyQ/s400/Acoel2.jpg" title="Waminoa Acoel Worms (Waminoa sp.)" width="400" /></a><br />
The Waminoa Acoels have been observed to infest many hard coral species, such as the favid coral (family Faviidae, probably <i>Goniastrea</i> spp.) above.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgbSvKg2V20S1xLXk0Lf8KxwNYmrfwROZqJbS1iz4QcGhN4gBs-fhIAnuWBpZkHpkdxcP0a6-UKzONh_kN7Nmv64452dV9iyIkSb0HlbqYXE5A25zvehYoxC23K1PJU-FcxLs0wTQ/s1600/Acoel1.jpg"><img alt="Waminoa Acoel Worms (Waminoa sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgbSvKg2V20S1xLXk0Lf8KxwNYmrfwROZqJbS1iz4QcGhN4gBs-fhIAnuWBpZkHpkdxcP0a6-UKzONh_kN7Nmv64452dV9iyIkSb0HlbqYXE5A25zvehYoxC23K1PJU-FcxLs0wTQ/s400/Acoel1.jpg" title="Waminoa Acoel Worms (Waminoa sp.)" width="400" /></a><br />
They also infest mushroom corals (family Fungiidae), such as the <i>Podabacia </i>sp. above.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbPpB0Z9vmv1zplF1euMZVDIXQAHK7f6287sF5v4tNWEK1j1p7MluGmIA52U2hmoHUINCWDPqnLIsl1xFvROCQgwfVD1Vpi-iSMXPoEBG2oh3kufkrNqaV2yEs-s9xCB53NTDHvQ/s1600/Waminoa4.jpg"><img alt="Waminoa Acoel Worms (Waminoa sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbPpB0Z9vmv1zplF1euMZVDIXQAHK7f6287sF5v4tNWEK1j1p7MluGmIA52U2hmoHUINCWDPqnLIsl1xFvROCQgwfVD1Vpi-iSMXPoEBG2oh3kufkrNqaV2yEs-s9xCB53NTDHvQ/s400/Waminoa4.jpg" title="Waminoa Acoel Worms (Waminoa sp.)" width="400" /></a><br />
While the acoels may not feed on the corals directly, it has been observed that some corals infested by them appear less healthy, such as the <b>Sunflower Mushroom Coral (<i>Heliofungia actiniformis</i>)</b> featured above. This coral appears sickly compared to the time <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjg5zcX5-op-Zkk0b5BuWo_wHTtFz2sjLjrxo84pk5bcFkUaKjqdsMP45YxCFDkNmC186PdAtM9D-P-_s7UwKEog7tbWhVIzyo4K2bHVYx0cjtUWcQsSkOKVPObjT0Ve4Py5IsJkg/s1600/Heliofungia-actiniformis.jpg">when it was not yet infested</a>.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgPS2QwNPlN5Voze9CX0PAiy1cNFNDcJxhx5csa1iZujDPaLxqDER7uX6rHnSMYbv7E4SAagTVcF-SdAW9dJLUGsmNgU0UtySj4SzG_tfB5SSBHPhKqvafN-dt_lXk8D1XQ7J0yNw/s1600/Acoel.jpg"><img alt="Acoels (Phylum Acoelomorpha)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgPS2QwNPlN5Voze9CX0PAiy1cNFNDcJxhx5csa1iZujDPaLxqDER7uX6rHnSMYbv7E4SAagTVcF-SdAW9dJLUGsmNgU0UtySj4SzG_tfB5SSBHPhKqvafN-dt_lXk8D1XQ7J0yNw/s400/Acoel.jpg" title="Acoels (Phylum Acoelomorpha)" width="400" /></a><br />
Acoel worms have been observed to infest <a href="http://tidechaser.blogspot.sg/2013/01/mushroom-anemones-corallimorphs.html">corallimorphs (order Corallimorpharia)</a> as well.<br />
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<b>References</b><br />
<ul style="text-align: left;">
<li>Achatz, J.G., M. Chiodin, W. Salvenmoser, S. Tyler & P. Martinez. 2012. The Acoela: on their kind and kinships, especially with nemertodermatids and xenoturbellids (Bilateria incertae sedis). <i>Organisms Diversity & Evolution</i>. </li>
<li>Burnie, D. 2001. <i>Animal</i>. London: Dorling Kindersley. 624 pp.</li>
<li>Hikosaka-Katayama T, Koike K, Yamashita H, Hikosaka A, Koike K. (2012) Mechanisms of Maternal Inheritance of Dinoflagellate Symbionts in the Acoelomorph Worm <i>Waminoa litus</i>. <i>Zool. Sci</i>. 29:559-567. </li>
<li>Mwinyi, A., X. Bailly, S J. Bourlat, U. Jondelius, D. T. J. Littlewood & L. Podsiadlowski. 2010. The phylogenetic position of Acoela as revealed by the complete mitochondrial genome of Symsagittifera roscoffensis. <i>BMC Evolutionary Biology</i> 10: 309. </li>
<li>Ng, P. K .L., R.T. Corlett & H.T.W. Tan (eds.). 2011. <i>Singapore Biodiversity: An Encyclopedia of the Natural Environment and Sustainable Development</i>. Singapore: Editions Didier Millet. 552 pp.</li>
<li>Philippe, H., H. Brinkmann, R. R. Copley, L. L. Moroz, H. Nakano, A. Poustka, A. Wallberg, K. J. Peterson & M. J. Telford. 2011. Acoelomorph flatworms are deuterostomes related to Xenoturbella. Nature, 470, 255–260.</li>
<li>Ruppert, E.E. and R.D. Barnes. 1991. <i>Invertebrate Zoology (International Edition)</i>. Saunders College Publishing. U.S.A. 1056 pp.</li>
</ul>
</div>
Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com0tag:blogger.com,1999:blog-9797239.post-82629717197743801062013-07-26T18:05:00.000+08:002013-07-26T18:09:19.085+08:00Malacostracans (Phylum Arthropoda: Class Malacostraca) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
The malacostracans (phylum Arthropoda, subphylum Crustacea, class Malacostraca) include the crustaceans that many people are familiar, such as crabs, lobsters, prawns and woodlice.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYoLvSl7Nal9VVyexx2UGxtOBxKEFBRvfgIA1DhYFjcTuPpBd0sVEZ-EYxwI4JX78_gSKuROYDjfpQ2eqRC0ouUJUUWVB1oaE256abMlA_Arcrl-oHIKPS2dGVp3AJJ7B3YNUnzQ/s1600/Malacostraca.jpg"><img alt="Malacostracans (class Malacostraca)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYoLvSl7Nal9VVyexx2UGxtOBxKEFBRvfgIA1DhYFjcTuPpBd0sVEZ-EYxwI4JX78_gSKuROYDjfpQ2eqRC0ouUJUUWVB1oaE256abMlA_Arcrl-oHIKPS2dGVp3AJJ7B3YNUnzQ/s400/Malacostraca.jpg" title="Malacostracans (class Malacostraca)" width="400" /></a><br />
While they may be very diverse in their appearances, they have several common features. Their body typically comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head may be fused with the thorax to form a cephalothorax. They often have a tough exoskeleton strengthened with calcium carbonate, and the carapace (if present) covers the gills but not the abdomen. They have prominent antennae, and up to three pairs of appendages may be modified into mouthparts for manipulating food.<br />
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As with other crustaceans, most malacostracans have two pairs of antennae and compound eyes on stalks. The abdomen ends off with a tail-like structure called a telson, and a flattened tail fan is usually present at the tip.<br />
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Most malacostracans reproduce sexually, though some are known to reproduce by parthenogenesis (the embryos develop without fertilisation). They usually have separate sexes, though a number of species are hermaphroditic (possessing both male and female reproductive parts), and some may change sex during the course of their lives. Most species carry the eggs until they are ready to hatch, though some release their eggs into the water. For aquatic species, the eggs will hatch into larvae that usually appear very different from the adults. For terrestrial species like the woodlouse, the young may appear similar to the adult but has fewer legs.<br />
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A wide variety of malacostracans can be found in Singapore, but only a few groups are readily seen and easy enough to distinguish from others. Hence, I will only include the few malacostracan groups that I have photographed in Singapore in this entry.<br />
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<u><b>A) Mantis Shrimps (Order Stomatopoda)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiFHeqW-hHDNHl0Dpd1_MOmGTtKAXRpUrDe3r3O3PquDir0MKxhVCJjJHWupNliquP4QWoe_aW0HP79fvpIeoTXzNUcLoOQ1aaoqv5WFBsAieCm7ULOeiQ7hrLgiQ2a_nWXeINSxQ/s1600/Stomatopods.jpg"><img alt="Mantis Shrimps (Order Stomatopoda)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiFHeqW-hHDNHl0Dpd1_MOmGTtKAXRpUrDe3r3O3PquDir0MKxhVCJjJHWupNliquP4QWoe_aW0HP79fvpIeoTXzNUcLoOQ1aaoqv5WFBsAieCm7ULOeiQ7hrLgiQ2a_nWXeINSxQ/s400/Stomatopods.jpg" title="Mantis Shrimps (Order Stomatopoda)" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/06/mantis-shrimps-stomatopoda-singapore.html">Mantis shrimps (order stomatopoda)</a> are elongate crustaceans with a pair of enlarged appendages that they carry folded beneath the head, somewhat similar to the forelimbs of a praying mantis. They can be divided into two main groups - the smashers and the spearers - based on the appearance of their striking appendages and how they are used. The smashers have a heavily calcified knob at the tip of the appendages for punching their prey, while the spearers have numerous sharps spines on the last segment of their claws to impale their prey.<br />
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<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/06/mantis-shrimps-stomatopoda-singapore.html">>> more</a></span></div>
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<u><b>B) Amphipods (Order Amphipoda)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9Cn8612UwnWS_FASMIbYyWHYW2K63wysLR4eKoa3DLyNE2pS4AgKUfOvfooVpfWM2F6jWNaNNDwxqqgGTZrEEPDlkaVScWijADJKAhqbaTaKXU__lvUXRieLDjX2YTsn80CyzGQ/s1600/Amphipods.jpg"><img alt="Amphipods (Order Amphipoda)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9Cn8612UwnWS_FASMIbYyWHYW2K63wysLR4eKoa3DLyNE2pS4AgKUfOvfooVpfWM2F6jWNaNNDwxqqgGTZrEEPDlkaVScWijADJKAhqbaTaKXU__lvUXRieLDjX2YTsn80CyzGQ/s400/Amphipods.jpg" title="Amphipods (Order Amphipoda)" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/06/sandhoppers-amphipods-amphipoda.html">Amphipods (order Amphipoda)</a> are crustaceans that lack a carapace and often appear laterally compressed. They are very diverse but often overlooked due to the small sizes of terrestrial and intertidal species. Unlike many crustaceans, their eyes are unstalked, and in front of the eyes are two pairs of antennae. They typically have seven pairs of walking legs (pereopods), with the first two pairs modified to assist in feeding. They have an additional three pairs of swimming legs (pleopods) at the back, and three more appendages (uropods) to help with locomotion.<br />
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<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/06/sandhoppers-amphipods-amphipoda.html">>> more</a></span></div>
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<u><b>C) Isopods (Order Isopoda)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgSNs3-frgBk8ARCgCdvdRyIg2__nQJVz9snZrxbYsQfmbnYi1fG_-Gkv37k8Khfd1PQDrjZDHcYN8LovO__5DmgNo3LOJEDLbY_4AsWiGQ3RvkHt11sdun-nR2NNQ8VzIjS8Y3bA/s1600/Isopods.jpg"><img alt="Isopods (Order Isopoda)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgSNs3-frgBk8ARCgCdvdRyIg2__nQJVz9snZrxbYsQfmbnYi1fG_-Gkv37k8Khfd1PQDrjZDHcYN8LovO__5DmgNo3LOJEDLbY_4AsWiGQ3RvkHt11sdun-nR2NNQ8VzIjS8Y3bA/s400/Isopods.jpg" title="Isopods (Order Isopoda)" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/06/woodlice-slaters-isopoda-singapore.html">Isopods (order Isopoda)</a> probably have the most diverse appearance among the crustaceans, ranging from flattened and bug-like, to longish and worm-like. Most of the ones seen on land and in shallow water have the former appearance though. They lack an obvious carapace, or have a much reduced one. With regards to their diet, some species are scavengers or detrital feeders, some are known to feed on algae, and some parasitise other animals, but generally, little is known about most isopods.<br />
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<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/06/woodlice-slaters-isopoda-singapore.html">>> more</a></span></div>
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<u><b>D) Decapods (Order Decapoda)</b></u><br />
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Decapods (order Decapoda) are very important to human, as many species are edible and important in the fishing and aquaculature industry. The body shapes of different groups differ greatly, from the elongate shrimps and lobsters to the short-bodied crabs. They can, however, be distinguished from other crustaceans by their five pairs of legs ("deca" means "ten", while "poda" means "feet") attached to the thorax. Some of these legs may have been modified to assist with feeding though, and some species may have additional appendages to help with locomotion. <br />
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Here are some of the decapods that I have photographed in local waters.<br />
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<b>1. Prawns (Suborder Dendrobranchiata)</b><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjWWIdhQSElw70CbLjYDInRz6RuyytnUZgJDcGlYBswQfNTWAjOhJ5GQe2H_FHxQ1gBAWLt3k1tS1VHjZQfVForQvdAKROe6Jbn_HH3SQ1f-xftMRQlWrtE2eH4ZN1ugBPuJWzI0Q/s1600/Prawns.jpg"><img alt="Prawns (Suborder Dendrobranchiata)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjWWIdhQSElw70CbLjYDInRz6RuyytnUZgJDcGlYBswQfNTWAjOhJ5GQe2H_FHxQ1gBAWLt3k1tS1VHjZQfVForQvdAKROe6Jbn_HH3SQ1f-xftMRQlWrtE2eH4ZN1ugBPuJWzI0Q/s400/Prawns.jpg" title="Prawns (Suborder Dendrobranchiata)" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/06/prawns-penaeidae-dendrobranchiata.html">Prawns (suborder Dendrobranchiata)</a> are distinguished from other similar-looking decapods by having gills that are branch-like. They also do not hold their eggs until they hatch, but release the fertilised eggs directly into the water column. While they are commonly called prawns in the region, they may be referred to as shrimps (not to be confused with the caridean shrimps) in other countries. They have an elongate body, and the first three pairs of legs have small pincers at the tip to assist with feeding. Most of the species seen in Singapore are of the family Penaeidae, and hence they are also often called penaeid prawns.<br />
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<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/06/prawns-penaeidae-dendrobranchiata.html">>> more</a></span></div>
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<b>2. Pleocyemates (Suborder Pleocyemata)</b><br />
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Members of this suborder typically have leaf-like gills or gills made up of unbranched filaments. They usually brood their eggs until they are ready to hatch.<br />
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<u><b>Crabs (Infraorder Brachyura)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhtLHz1yfm0KuS_bukKHRDIIXyp2H-GW066FQSEtYIxtfpypYNxkAyHyBnf9_nFlB33hXCdwz2MUMVp9tSeESQukaOOZyD6QWNhs7FyJ8ONQC1mMGjAKzyIUHT4qAMSa5B9w5w5/s1600/Crabs.jpg"><img alt="Crabs (Infraorder Brachyura)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhtLHz1yfm0KuS_bukKHRDIIXyp2H-GW066FQSEtYIxtfpypYNxkAyHyBnf9_nFlB33hXCdwz2MUMVp9tSeESQukaOOZyD6QWNhs7FyJ8ONQC1mMGjAKzyIUHT4qAMSa5B9w5w5/s400/Crabs.jpg" title="Crabs (Infraorder Brachyura)" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/true-crabs-brachyura-singapore.html">Crabs (infraorder Brachyura)</a> can be recognised by their four pairs of walking legs, a pair of clawed arms, a broad carapace, and a very short and flattened abdomen which is usually folded underneath the body. The abdomen of females is usually broader, so as to carry the eggs. Their antennae are relatively short, and their eyes are on stalks. As this is a very huge group with many species, I will provide more details and photos of local examples in a separate page in the near future.<br />
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<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/07/true-crabs-brachyura-singapore.html">>> more</a></span></div>
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<u><b>Anomurans (Infraorder Anomura)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhIRahK9fU1PfZYeY1JcPs8CTLhy1npWWLitT0qBcZ2_hdtErN3eNcjjwORmU5uj9rk_OJsmqYzIX_Tby-0C0XgrgUv1jBxfzbDNVHPC1oj2Xlt1k8PVATDVV4V8Oa3SA5F1OWU/s1600/Anomura.jpg"><img alt="Anomurans (Infraorder Anomura)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhIRahK9fU1PfZYeY1JcPs8CTLhy1npWWLitT0qBcZ2_hdtErN3eNcjjwORmU5uj9rk_OJsmqYzIX_Tby-0C0XgrgUv1jBxfzbDNVHPC1oj2Xlt1k8PVATDVV4V8Oa3SA5F1OWU/s400/Anomura.jpg" title="Anomurans (Infraorder Anomura)" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/porcelain-hermit-crabs-anomura-singapore.html">Anomurans (infraorder Anomura)</a> include the hermit crabs, porcelain crabs, king crabs and their allies. They are often crab-like, but have long antennae and three or less pairs of obvious walking legs. The number of walking legs may not always be a useful feature though, as some true crabs have some of their legs modified for functions other than walking, and hence may have fewer than four pairs of walking legs. As there are a number of species in this group that I have photographed, I will provide more details and photos in a separate page in the near future.<br />
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<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/07/porcelain-hermit-crabs-anomura-singapore.html">>> more</a></span></div>
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<u><b>Caridean Shrimps (Infraorder Caridea)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEinb6CULBktT8SLf6PVLqb2onZTVIocmzJ-f6yydcbqqbpdo1r5Tm9omVbCFvgq0AUBLl0DgWeK9XS0nZPcRjkWtyDrFzjcqnXeoF3B0vZipjOv6hgBAv0_9qNtGbTtDfL4ikN2gQ/s1600/Shrimps.jpg"><img alt="Caridean Shrimps (Infraorder Caridea)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEinb6CULBktT8SLf6PVLqb2onZTVIocmzJ-f6yydcbqqbpdo1r5Tm9omVbCFvgq0AUBLl0DgWeK9XS0nZPcRjkWtyDrFzjcqnXeoF3B0vZipjOv6hgBAv0_9qNtGbTtDfL4ikN2gQ/s400/Shrimps.jpg" title="Caridean Shrimps (Infraorder Caridea)" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/shrimps-caridea-singapore.html">Caridean shrimps (infraorder Caridea)</a> appear very similar to penaeid prawns, with their elongate abdomen. Their five pairs of legs are all well-developed, but unlike the penaeid prawns, the third pair does not have pincers at the tip. Also, the second horizontal plate of the abdomen is enlarged, covering part of the first segment and the third segment. Unlike the prawns that release their eggs into the water, caridean shrimps brood their eggs under their abdomen until they hatch. As there are a number of species in this group that I have photographed, I will provide more details and photos in a separate page in the near future.<br />
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<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/07/shrimps-caridea-singapore.html">>> more</a></span></div>
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<u><b>Mud Lobsters & Mud Shrimps (Infraorder Gebiidea) </b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQqx1ZOVOl0NqjadvZZYOFK0zdVHK0_LLRGS0Ax3MT8gQJpIG_2srXJNlh7jMc5P0Bjf8LVCKiHe05R1H4Rc_ynizY5q-v3NjtWdPYz2lsSdOV-Gf6KE5psi4mIrVRDuKpeltG_w/s1600/Gebiidea.jpg"><img alt="Mud Lobsters & Mud Shrimps (Infraorder Gebiidea" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQqx1ZOVOl0NqjadvZZYOFK0zdVHK0_LLRGS0Ax3MT8gQJpIG_2srXJNlh7jMc5P0Bjf8LVCKiHe05R1H4Rc_ynizY5q-v3NjtWdPYz2lsSdOV-Gf6KE5psi4mIrVRDuKpeltG_w/s400/Gebiidea.jpg" title="Mud Lobsters & Mud Shrimps (Infraorder Gebiidea" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/06/mud-lobsters-shrimps-gebiidea-singapore.html">Mud lobsters & mud shrimps (Infraorder Gebiidea)</a> are burrowing crustaceans with elongate and somewhat flattened abdomens that live mostly in soft-bottoms of intertidal or subtidal areas. The ones with a heavily calcified exoskeleton decorated with spines and tubercles are usually referred to as mud lobsters, while the more delicate members are referred to as mud shrimps. Some species may appear similar to the coral ghost shrimps of the infraorder Axiidea, but can be distinguished from the latter by having pincers on the first pair of legs, and very reduced or no pincers on the second pair, instead of having well-developed pincers on the first two pairs of legs. I will provide more details and photos in a separate page in the near future.<br />
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<u><b>Spiny Lobsters & Allies (Infraorder Achelata)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjEBDwaWPr9ifvllhB-JMCtHBN5Rj3o4ZIVtegVXpzoh5liaKWtyqUu4A0ArwQg-5VTNroTOdvCrMlUcWalo4IAUwrqth_3Ur3Dtasqa8MZtY4DpeeDQvLSUM9LWs1lt9RixlIT0A/s1600/Lobsters.jpg"><img alt="Spiny Lobsters & Allies (Infraorder Achelata)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjEBDwaWPr9ifvllhB-JMCtHBN5Rj3o4ZIVtegVXpzoh5liaKWtyqUu4A0ArwQg-5VTNroTOdvCrMlUcWalo4IAUwrqth_3Ur3Dtasqa8MZtY4DpeeDQvLSUM9LWs1lt9RixlIT0A/s400/Lobsters.jpg" title="Spiny Lobsters & Allies (Infraorder Achelata)" width="400" /></a><br />
Spiny lobsters and allies (infraorder Achelata) are not true lobsters, and they can be distinguished from the latter by the lack of true claws with pincers. They have a soft and flexible tail, and a broad tail fan which allows them to swim rapidly backwards over a short distance. The rostrum (a pointy structure at the front of the head) is usually very small or absent. Many species are scavengers, though studies suggest that they may be opportunists which take a variety of food. While lobsters are occasionally seen by divers in local waters, some of the bigger specimens seen could be those released for religious merit-making. The above picture features a Painted Spiny Lobster (<i>Panulirus versicolor</i>) in the main image, and a dead Mud Spiny Lobster (<i>Panulirus polyhagus</i>) in the inset.<br />
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<b>References</b><br />
<ul style="text-align: left;">
<li>Bartlett, T. & J. VanDyk. 2003. <i>BugGuide</i>. Retrieved May 24, 2013, http://bugguide.net.</li>
<li>Burnie, D. 2001. <i>Animal</i>. London: Dorling Kindersley. 624 pp.</li>
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>Carpenter, K. E. & V. H. Niem (eds), 1998-2001. <i>FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific</i>. Volumes 1 to 6. FAO, Rome. pp. 1-4218.</li>
<li>Debelius, H. 1999. <i>Crustacea - Guide of the world</i>. IKAN, Frankfurt. 321pp. </li>
<li>Dworschak, P. C., D. L. Felder & C. C. Tudge. 2012. Infraorders Axiidea de Saint Laurent, 1979 and Gebiidea de Saint Laurent, 1979 (formerly known collectively as Thalassinidea). In: Schram, F.R., J.C. von Vaupel Klein, M. Charmantier-Daures, and J. Forest (eds.) <i>Treatise on zoology - Anatomy, taxonomy, biology - The crustacea, decapoda</i>, Volume 9 Part B Decapoda: Astacidea P.P. (Enoplometopoidea, Nephropoidea), Glypheidea, Axiidea, Gebiidea, and Anomura. Vol. 9B. Pp. 109–219 </li>
<li>McGavin, G. 2000. <i>Dorling Kindersley Handbooks: Insects, spiders and other terrestrial arthropods</i>. London: Dorling Kindersley. 255 pp.</li>
<li>Moh, H. H. & Chong, V. C. 2009. A new species of Thalassina (Crustacea: Decapoda: Thalassinidea) from Malaysia. <i>Raffles Bulletin of Zoology</i>, 57, 465-473. </li>
<li>Ng, P. K. L., S. S. L. Lim, L. K. Wang & L. W. H. Tan. 2007. <i>Private lives: An exposé of Singapore's shores</i>. The Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 212 pp.</li>
<li>Ng, P. K .L., R.T. Corlett & H.T.W. Tan (eds.). 2011. <i>Singapore biodiversity: An encyclopedia of the natural environment and sustainable development</i>. Singapore: Editions Didier Millet. 552 pp.</li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
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Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com0tag:blogger.com,1999:blog-9797239.post-44305175341930790952013-07-26T18:01:00.001+08:002013-07-26T18:02:08.673+08:00True Crabs (Phylum Arthropoda: Infraorder Brachyura) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
True crabs (phylum Arthropoda, subphylum Crustacea, class Malacostraca, order Decapoda, suborder Pleocyemata, infraorder Brachyura) are a group of crustaceans that most people in the region are familiar with, since many species are widely consumed in the region.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhtLHz1yfm0KuS_bukKHRDIIXyp2H-GW066FQSEtYIxtfpypYNxkAyHyBnf9_nFlB33hXCdwz2MUMVp9tSeESQukaOOZyD6QWNhs7FyJ8ONQC1mMGjAKzyIUHT4qAMSa5B9w5w5/s1600/Crabs.jpg"><img alt="Crabs (Infraorder Brachyura)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhtLHz1yfm0KuS_bukKHRDIIXyp2H-GW066FQSEtYIxtfpypYNxkAyHyBnf9_nFlB33hXCdwz2MUMVp9tSeESQukaOOZyD6QWNhs7FyJ8ONQC1mMGjAKzyIUHT4qAMSa5B9w5w5/s400/Crabs.jpg" title="Crabs (Infraorder Brachyura)" width="400" /></a><br />
They are of the order Decapoda, and like other members of this order, they have five pairs of "legs", including the clawed arms ("deca" means "ten", while "poda" means "feet"). They also have leaf-like gills, a distinctive characteristic of decapods from the suborder Pleocyemata. And as with other crustaceans from the class Malacostraca, their body comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head is fused with the thorax to form a cephalothorax. They have a tough exoskeleton strengthened with calcium carbonate, and the carapace covers the gills but not the abdomen.<br />
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They can be distinguished from other similar-looking decapods by having a broad carapace, a very short and flattened abdomen which is usually folded underneath the body, a pair of clawed arms, and four pairs of walking legs. Sometimes, one or more pairs of legs may be modified for swimming or other purposes. Their antennae are relatively short, and their eyes are on stalks.<br />
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They have separate sexes, and reproduce sexually. The females can usually be distinguished from the males by having a broader abdomen. This is an adaptation to allow them to carry the eggs under the abdomen until they hatch.<br />
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Here are some of the families of marine crabs that I have photographed in local waters. I will elaborate on the <a href="http://tidechaser.blogspot.sg/2013/07/freshwater-crabs-shrimps-singapore.html">freshwater crabs in a separate page</a>.<br />
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<u><b>A) Elbow Crabs (Family Parthenopidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhstAOqXH_-TGx7GYogHDqQLdoirpSjtXSIs1Wb51Liq6ZzSPvBHKbqn8xt5W651QWbPvpRHulc3ZmgMjhvD3OyX75b9Cmbq2BOvUKhXVVS73TmAngVaRNw5vc1JT5XEJcDnBm3qA/s1600/Parthenopidae.jpg"><img alt="Elbow Crabs (Family Parthenopidae)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhstAOqXH_-TGx7GYogHDqQLdoirpSjtXSIs1Wb51Liq6ZzSPvBHKbqn8xt5W651QWbPvpRHulc3ZmgMjhvD3OyX75b9Cmbq2BOvUKhXVVS73TmAngVaRNw5vc1JT5XEJcDnBm3qA/s400/Parthenopidae.jpg" title="Elbow Crabs (Family Parthenopidae)" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/elbow-crabs-parthenopidae-singapore.html">Elbow crabs (superfamily Parthenopoidea, family Parthenopidae)</a> typically have long to very long chelipeds (clawed arms) that they usually cannot hide completely beneath the carapace. These long chelipeds gave them their common name, as the joint in the middle resembles an elbow. Despite the chelipeds being so long, the fingers (or pincers) at the tip are usually unable to reach the back of the carapace. Many species have fine hair on the exoskeleton, which traps sediment and help the animal to camouflage. The surface of the exoskeleton is often uneven with ridges, bumps and spines. Studies suggest that they have a omnivorous diet, and possibly hunt for small invertebrates by ambush using their long chelipeds, with aid from their excellent camouflage.<br />
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<u><b>B) Box Crabs (Family Calappidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhB4RZBbmDUiGkNHya_iSUqTFfs10QjfHcXkFIcGFTbh42oriQj_8K5Ohv3pXrRUdVE12ur9TH9QFDzr0QhtmHFxREIdLsNtqhA9_lAcn7qMUxL_8f5h7fFpd1xgkz3ejNVeEdjQw/s1600/Calappidae.jpg"><img alt="Box Crabs (Family Calappidae)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhB4RZBbmDUiGkNHya_iSUqTFfs10QjfHcXkFIcGFTbh42oriQj_8K5Ohv3pXrRUdVE12ur9TH9QFDzr0QhtmHFxREIdLsNtqhA9_lAcn7qMUxL_8f5h7fFpd1xgkz3ejNVeEdjQw/s400/Calappidae.jpg" title="Box Crabs (Family Calappidae)" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/box-crabs-calappidae-singapore.html">Box crabs (superfamily Calappoidea, family Calappidae)</a> got their common name from their box-like appearances (with some imagination). They can be recognised by the somewhat rounded or oval carapace, the relatively narrow gap between the eye, and the laterally compressed chelipeds (which are usually held close to their mouthparts). The chelipeds are asymmetrical. The right pincer has a curved tooth near the base of the upper finger, which the crab will stick it into the opening of a snail, and use it much like a can-opening to cut a channel through the shell. The crab will then use the left pincer, which is more slender and has forcep-like fingers, to extract the exposed snail from its shell. Most species are good burrowers, and are found on sandy substrates.<br />
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<u><b>C) Moon Crabs (Family Matutidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhS0r4FLVlfi8mY3gXpT68rXfyWlTGu7zXTLZOqaegYdoH8Zb6TIAFgMSR_Q2_5Sr2FZ2SukE-y6aAGUjO7wV6TNtm4Auuqm2xIfMiMijd_2po8fLLSDssy1BoVz7kr0XG5TgdI5g/s1600/Matutidae.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhS0r4FLVlfi8mY3gXpT68rXfyWlTGu7zXTLZOqaegYdoH8Zb6TIAFgMSR_Q2_5Sr2FZ2SukE-y6aAGUjO7wV6TNtm4Auuqm2xIfMiMijd_2po8fLLSDssy1BoVz7kr0XG5TgdI5g/s400/Matutidae.jpg" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/moon-crabs-matutidae-singapore.html">Moon crabs (superfamily Calappoidea, family Matutidae)</a> are mostly nocturnal, and got their common name from their typically pale round carapace. A long spine is usually present on the left and right sides of the carapace, and all their legs are distinctly flattened laterally into paddle-like structures. They are good swimmers and burrowers, and are usually found on sandy substrates. Most moon crabs feed on small invertebrates or scavenges.<br />
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<u><b>D) Swimming Crabs (Family Portunidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiIuogIP8xBAJInCwvAsLQqprbAq6orJqgGYm6tTrqXx0XNfX-YyK4RT4U1t7XZNzcfn3NDxv9RhbaCISqJMceRR6XFAyz_-RTTJlVPzwJQL_Ipn_FBTHzT1bDNszVe2wBLg3lr3g/s1600/Portunidae.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiIuogIP8xBAJInCwvAsLQqprbAq6orJqgGYm6tTrqXx0XNfX-YyK4RT4U1t7XZNzcfn3NDxv9RhbaCISqJMceRR6XFAyz_-RTTJlVPzwJQL_Ipn_FBTHzT1bDNszVe2wBLg3lr3g/s400/Portunidae.jpg" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/swimming-crabs-portunidae-singapore.html">Swimming crabs (superfamily Portunoidea, family Portunidae)</a> are so-named as the last pair of legs are paddle-like, making them good swimmers. The carapaces of most species are somewhat hexagonal, and the margin of the front half is often lined with sharp teeth. The various species live in a variety of habitats, from soft substrates like mudflats and sandflats to harder bottoms like coral reefs and rubble. The diet varies between the species as well, ranging from slow-moving prey such as snails and annelids to fast-moving ones such as fish and shrimps.<br />
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<u><b>E) Rubble Crabs (Family Xanthidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglx3C6a21rS4Q6zF2PeAyBmJLDuSJ28YlNGNGQlRAIi0K3cxG8MWFDlxPtD_sedjgQUhJT-rHrRtVGKP4YK41hbT5SDjOu3TW5k9OGmEllipvrrXQG8XFD2DtIkvQUZxnRhTXo5Q/s1600/Xanthidae.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglx3C6a21rS4Q6zF2PeAyBmJLDuSJ28YlNGNGQlRAIi0K3cxG8MWFDlxPtD_sedjgQUhJT-rHrRtVGKP4YK41hbT5SDjOu3TW5k9OGmEllipvrrXQG8XFD2DtIkvQUZxnRhTXo5Q/s400/Xanthidae.jpg" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/rubble-crabs-xanthidae-singapore.html">Rubble crabs (superfamily Xanthoidea, family Xanthidae)</a> are mostly found living among coral rubble, in coral reefs, and rocky shores. They come in a variety of shapes, and the carapace can be hexagonal to rounded. Some species may have numerous sharp spines, while others may have blunt lobes or are unarmed. The fingers of the pincers of some species may be spoon-tipped to aid with the scraping of algae from rocks. For most species, the frontal margin between the eyes usually have a notch in the middle. Many species feed on algae, and as a result a number of them are known to be poisonous, due to the toxin in the algae they feed on. Some of the most poisonous crabs in the region are of this family.<br />
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<u><b>F) Stone Crabs (Family Menippidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQOeWutX8-TGgGWIlaXRBPGIS5jfMBzjGL89Yj54JmLAVKEaUYveSozNYijHKs7L8whYEUDi4sKPHnDfez9hxWWvOfDEfjDXukiX8UigBTKHyQ_mcIxfCmJqvnOII5oSqEXbiuPw/s1600/Menippidae.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQOeWutX8-TGgGWIlaXRBPGIS5jfMBzjGL89Yj54JmLAVKEaUYveSozNYijHKs7L8whYEUDi4sKPHnDfez9hxWWvOfDEfjDXukiX8UigBTKHyQ_mcIxfCmJqvnOII5oSqEXbiuPw/s400/Menippidae.jpg" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/stone-crabs-menippidae-singapore.html">Stone crabs (superfamily Eriphioidea, family Menippidae)</a> are commonly found in rocky areas or areas with coral rubble. Their carapace is usually somewhat hexagonal to ovate, and the margin near the front is usually marked with crested teeth (i.e. the top surface of the teeth is not flat, but ridge-like, somewhat like the corner of a roof). They typically have large and powerful asymmetrical chelipeds, and a large molar-like tooth can be found near the base of the top finger, allowing them to crush and break shells of molluscan prey. <br />
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<u><b>G) Forcep Crabs (Family Oziidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhBYg6bqzp8Bgbk7E7hvBLunVp1gZDmq3mXRCc7NldqHZWeVzTjNeGfLl_WEvMexux_5Kv5ebuZEmZuDsjU10o2nv2EyFT1qlOXH9ju9D1nlvg9V1vgYiGu7x4H30_TLL3Sx9Q_zw/s1600/Oziidae.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhBYg6bqzp8Bgbk7E7hvBLunVp1gZDmq3mXRCc7NldqHZWeVzTjNeGfLl_WEvMexux_5Kv5ebuZEmZuDsjU10o2nv2EyFT1qlOXH9ju9D1nlvg9V1vgYiGu7x4H30_TLL3Sx9Q_zw/s400/Oziidae.jpg" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/forceps-crabs-oziidae-singapore.html">Forceps crabs (superfamily Eriphioidea, family Oziidae)</a> typically have asymmetrical chelipeds, with the larger one having a gently curved tooth at the base of the top finger, and the smaller cheliped with slender fingers, much like a pair of forceps. Like the box crabs, the curved tooth is for cutting into the opening of snails, while the forcep-like pincers extract the flesh from the shell. Some species may develop a molariform tooth as the crab matures, which allows the crab to crush snail shells as well. The carapace may be hexagonal or ovate, the front half of the margin is lined with numerous teeth. Forceps crabs are usually found hiding among rocks or roots.<br />
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<u><b>H) Red-eyed Crabs (Family Eriphiidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiaTo6L3dBHskzlAL7OQS71w3xzQu-cHqfw5p-q-uFwjJJ2rJs5xQSmf8AT6glCCdvAdaTcyxTTN1j4ZvFGHV6U-4BzckmIK5n3NO98yqxp0amy8sLdMkz5IuaJy3zTzVZwHZrZYQ/s1600/Eriphiidae.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiaTo6L3dBHskzlAL7OQS71w3xzQu-cHqfw5p-q-uFwjJJ2rJs5xQSmf8AT6glCCdvAdaTcyxTTN1j4ZvFGHV6U-4BzckmIK5n3NO98yqxp0amy8sLdMkz5IuaJy3zTzVZwHZrZYQ/s400/Eriphiidae.jpg" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/red-eyed-crabs-eriphiidae-singapore.html">Red-eyed crabs (superfamily Eriphioidea, family Eriphiidae)</a> typically have red eyes, though this is not a useful distinguishing feature since may other crabs share this characteristic. They have hexagonal to ovate carapace, and the chelipeds are usually large and powerful. Both carapace and chelipeds are usually covered in fine, spiky bumps, and the front margin of the carapace is usually marked with lobes or spines. They typically have large and powerful asymmetrical chelipeds, and a large molar-like tooth can be found near the base of the top finger, allowing them to crush and break shells of molluscan prey. Studies suggest that some species include algae as part of their diet as well.<br />
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<u><b>I) Hairy Crabs (Family Pilumnidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjuuBSIqp_VJHeZIWzA5pC_aYCG7WBFthFvOsEHDIQE58v9ty8bzIl8Fw4s3cmT3BpE5Cy63yCLIcP-TUpGBDCtyffZwS1kWbv7-tbZu4YsYCOh4o14IZOi48fcDJC1z3wR8qRIOA/s1600/Pilumnidae.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjuuBSIqp_VJHeZIWzA5pC_aYCG7WBFthFvOsEHDIQE58v9ty8bzIl8Fw4s3cmT3BpE5Cy63yCLIcP-TUpGBDCtyffZwS1kWbv7-tbZu4YsYCOh4o14IZOi48fcDJC1z3wR8qRIOA/s400/Pilumnidae.jpg" width="400" /></a>
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<a href="http://tidechaser.blogspot.sg/2013/07/hairy-crabs-pilumnidae-singapore.html">Hairy crabs (superfamily Pilumnoidea, family Pilumnidae)</a>, despite the common name, do not always spot a hairy appearance. Most of the commonly seen species in Singapore have hairy or granulated exoskeletons though. The hair helps to break the shape of the animal and trap sediment, and hence allows it to camouflage with the surrounding. Some species can be confused with those from the previous family, but they can be distinguished by the lack of a large tooth at the base of the upper finger of the pincer. The carapace is usually hexagonal or somewhat ovate. Some hairy crabs are found to be poisonous, possibly due to their diet of marine algae and sessile cnidarians (such as zoanthids) which may harbour toxins.<br />
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<u><b>J) Acropora Crabs (Family Tetraliidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWvNqTiOtIf4mtW1RI4mdAw-CM0cmdJ2_RLWwTKrgAO2A0OCSR-A06U8B3hPdIiK-PY_QeIQfNn0j10xQq9aHoJn0KmIvCEdynAgG04jfyDtN3XTOIJIqgwPBWYZZpAh3xjeGseQ/s1600/Tetralia-nigrolineata.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWvNqTiOtIf4mtW1RI4mdAw-CM0cmdJ2_RLWwTKrgAO2A0OCSR-A06U8B3hPdIiK-PY_QeIQfNn0j10xQq9aHoJn0KmIvCEdynAgG04jfyDtN3XTOIJIqgwPBWYZZpAh3xjeGseQ/s400/Tetralia-nigrolineata.jpg" width="400" /></a><br />
<b>Acropora crabs (superfamily Trapezioidea, family Tetraliidae)</b> are often found living in Acropora corals (<i>Acropora </i>spp.). They were previously placed in the family Trapeziidae, but were recently placed in their own family. Acropora Crabs typically have a smooth trapezoidal to somewhat ovate carapace, usually with the back end narrower than the front end. One cheliped is conspicuously bigger than the other. The front margin of the carapace is straight but serrated (those of trapeziid crabs have four lobes or spines). They can be most readily distinguished from trapeziid crabs by having six movable abdominal segments instead of the third to fifth segments being fused. In addition, there is usually an obvious band of a different colour from the rest of the body running across the face of the crab. These crabs feed on the mucus produced by the corals, and in return defend the host with their powerful claws from potential coral predators. I have only seen one species in Singapore so far - the <b>Zorro Crab (<i>Tetralia nigrolineata</i>)</b> which got its common name from the black band on its head.<br />
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<u><b>K) Trapeziid Crabs (Family Trapeziidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiW-ckLdR0NR9hOPTtXu7jKBaeQ9utHbtdnqstOltOFLGZxAI50wr-VjUdVSi_73gBRdQiRTVyU9gOIJrDra8WndaPSEXU1wqB522DroOOUpyrf8wfES9qcZ9xJ-BzXASJ6cwxFOg/s1600/Trapeziidae.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiW-ckLdR0NR9hOPTtXu7jKBaeQ9utHbtdnqstOltOFLGZxAI50wr-VjUdVSi_73gBRdQiRTVyU9gOIJrDra8WndaPSEXU1wqB522DroOOUpyrf8wfES9qcZ9xJ-BzXASJ6cwxFOg/s400/Trapeziidae.jpg" width="400" /></a>
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<b>Trapeziid crabs (superfamily Trapezioidea, family Trapeziidae)</b> are known to live several genera of hard corals. The chelipeds are usually equal or somewhat equal in sizes. They can be distinguished from the previous group by having the third to fifth segments of the abdomen being fused. The carapace may be trapezoidal, hexagonal, octogonal or somewhat ovate, with the surface being smooth, polished, or finely granular, while the front margin is marked with four lobes or broad teeth. The outer surfaces of the pincers are usually smooth. The species seen in Singapore are mostly found on the hard coral, <i>Pocillopora damicornis</i>. Apologies for the poor picture feature above, as I have yet to get good photos of this group. It features a <b>Red Coral Crab (<i>Trapezia cymodoce</i>)</b>.<br />
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<u><b>L) Sesarmid Crabs (Family Sesarmidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioYlrN3IF37QPx5auzNm7aaeYOKO8zymsXut2BfOeJ7daTXRMgTj4Y1aMR5uhWIiDIJG8Ap34Loyz6g2qmTgdKBZKhgpVjCOL_MEZzt9P25KT6H7cZ884FU4gbHcjNHBJmBmrAIA/s1600/Sesarmidae.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioYlrN3IF37QPx5auzNm7aaeYOKO8zymsXut2BfOeJ7daTXRMgTj4Y1aMR5uhWIiDIJG8Ap34Loyz6g2qmTgdKBZKhgpVjCOL_MEZzt9P25KT6H7cZ884FU4gbHcjNHBJmBmrAIA/s400/Sesarmidae.jpg" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/climber-crabs-sesarmidae-singapore.html">Sesarmid crabs (superfamily Grapsidoidea, family Sesarmidae)</a> typically have a squarish carapace that is rough and covered with granules. They are often good climbers, with the tips of their legs pointed and hook-like, allowing them to easily climb up trees or mud mounds. Their "face" - the area below the eyes by the two sides of the mouthparts - is densely covered with short, stiff hair (or setae) in a network-like (reticulated) pattern. The eyes are wide apart at the two front corners of the carapace. Also, the male's abdomen rarely cover the space between the last pair of legs. They are mostly found in mangroves, and feed mostly on plant materials. The inner edges of the pincers are usually quite sharp, allowing them to cut up leaves.<br />
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<u><b>M) Grapsid Crabs (Family Grapsidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5Tg12mlHw7BCHCHnUWLCV4VQmQNYr4YbAMHRs1Izd6CJSLpo7V2K_CU6p3NCAiqbXF-njcHOqY5g6347oSxoNPkhyxEK4rmVHQk5CdNCS_nSnGiyQESf8bqdhbq5PO2-emJlwJg/s1600/Grapsidae.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5Tg12mlHw7BCHCHnUWLCV4VQmQNYr4YbAMHRs1Izd6CJSLpo7V2K_CU6p3NCAiqbXF-njcHOqY5g6347oSxoNPkhyxEK4rmVHQk5CdNCS_nSnGiyQESf8bqdhbq5PO2-emJlwJg/s400/Grapsidae.jpg" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/grapsid-crabs-grapsidae-singapore.html">Grapsid crabs (superfamily Grapsidoidea, family Grapsidae)</a> have squarish, rectangular, trapezoidal or circular carapaces. Unlike the previous family, the short hair on the face of grapsid crabs do not form network-like patterns. In addition, the abdomen of the males generally fill up the whole space between the last pair of legs. They can be found in mangroves or rocky shores, feeding on both plant materials and also small shore animals. The sharply pointed tips of their legs allow them to climb up trees and over rocks effectively. Grapsid crabs can be confused with members of the next family, the plagusiids. They can be distinguished by their mouthparts - the gap between the third pair of feeding appendages (or maxillipeds)
is not distinctly rhomboidal, unlike those of the plagusiids. In addition, the third to fifth abdominal segments of grapsid crabs are freely movable for most species, while those of the plagusiids are fused and immovable.<br />
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<u><b>N) Plagusiid Crabs (Family Plagusiidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTrnimHsrI3LyIWKATAAEw7yFST9IHBSUaQBdkweZn5tofBwYLyPg9PxWsRyxbwm422C_ayh5oiWCy42Iz0Mf8ohHzrRgXkzWVdpg23yXXMxTi2P4IEVo59Lgu_4xGeQSCqYlpZQ/s1600/Plagusia-squamosa.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTrnimHsrI3LyIWKATAAEw7yFST9IHBSUaQBdkweZn5tofBwYLyPg9PxWsRyxbwm422C_ayh5oiWCy42Iz0Mf8ohHzrRgXkzWVdpg23yXXMxTi2P4IEVo59Lgu_4xGeQSCqYlpZQ/s400/Plagusia-squamosa.jpg" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/plagusia-plagusiid-crabs-singapore.html">Plagusiid crabs (superfamily Grapsidoidea, family Plagusiidae)</a> are easily confused with species of the previous family, except that the third to sixth segments of the abdomen are fused and immovable, while the third to fifth abdominal segments of grapsid crabs are freely movable for most species. In addition, the mouthparts are different - the gap between the third pair of feeding appendages (or maxillipeds) is not distinctly rhomboidal, unlike those of the grapsids. These differences can be hard to examine in the field, but fortunately, this family is only represented by one genus in Singapore, <i>Plagusia</i>, which can be easily recognised by the numerous tiny bumps covering the exoskeleton. They are usually found on rocky shores, and the relatively long legs allow them to move from rock to rock quickly. They feed mostly on seaweed, and occasionally small animals. They are commonly called Rafting Crabs as they are often found living on flotsam and even pelagic marine animals.<br />
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<u><b>O) Varunid Crabs (Family Varunidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhy9_qTTsv37uhUVHkMsxfPEeEzZcUlRzLrI69ePq-T5L5usRLE6PBXjGVw76S8e0vWu3pwxpohNQXE_ObrqGyWAeGV5xanKRVmx5UqUsBALWh3L1NOVC38HPDypTJfLrNb3457Vg/s1600/Varunidae.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhy9_qTTsv37uhUVHkMsxfPEeEzZcUlRzLrI69ePq-T5L5usRLE6PBXjGVw76S8e0vWu3pwxpohNQXE_ObrqGyWAeGV5xanKRVmx5UqUsBALWh3L1NOVC38HPDypTJfLrNb3457Vg/s400/Varunidae.jpg" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/varunid-crabs-varunidae-singapore.html">Varunid crabs (superfamily Grapsidoidea, family Varunidae)</a> typically have smooth, squarish carapaces with the front margin lacking any lobes or teeth. The abdomen of the males rarely covers the whole space between the last pair of legs, and all abdominal segments are movable. Most species live in the mangrove or mudflats, though some may also be found on drift woods and flotsam out in the sea. Some are known to be able to survive in both fresh and salt water. Their legs are broad and often lined with hair, allowing them to swim for short distances. Varunid crabs are omnivorous, and some have been observe to scavenge.<br />
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<u><b>P) Sentinel Crabs (Family Macrophthalmidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiLW6VMUjHVUnhZjuuki0ZiGs8x8vz0aW6VjfwIlMMFlk6HVDfH8UZ1lYP_MArIOUGH-XipI_Kix5mUFWk8xcW1EEFZgFyDUbJ-HsYoWaN1uNA-Ne_5_tJHcSMtzdNcBmfYJUjj8Q/s1600/Macrophthalmidae.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiLW6VMUjHVUnhZjuuki0ZiGs8x8vz0aW6VjfwIlMMFlk6HVDfH8UZ1lYP_MArIOUGH-XipI_Kix5mUFWk8xcW1EEFZgFyDUbJ-HsYoWaN1uNA-Ne_5_tJHcSMtzdNcBmfYJUjj8Q/s400/Macrophthalmidae.jpg" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/sentinel-crabs-macrophthalmus.html">Sentinel crabs (superfamily Ocypodoidea, family Macrophthalmidae)</a> can usually be recognised by their extremely long and thin eyestalks. The carapace is usually quadrilateral, broader than long, and lined with teeth by the sides. The chelipeds are somewhat equal in size. They are usually found on soft substrates, such as mud and sand. The long eyestalks allow them to see all around (even behind), so that they can quickly burrow into the soft substrate to hide from predator. They feed on tiny decaying organic materials (or detritus) and small invertebrates. These crabs often build burrows with a distinctive opening - either rectangular or ovate in shape.<br />
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<u><b>Q) Ocypodid Crabs (Family Ocypodidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkvDOlERdmUKNkAQWfGJ55vWK0uCOhw7CQhtq9IpWqjbaKOpjX_obmlUPOHIjC5msIk0eeJ7QO6KcQ2pauhvdL6BvmdFlZFny72xUN_-_peR4D1h25o1rT0FvE5Z1VZvrTAeu0OA/s1600/Ocypodidae.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkvDOlERdmUKNkAQWfGJ55vWK0uCOhw7CQhtq9IpWqjbaKOpjX_obmlUPOHIjC5msIk0eeJ7QO6KcQ2pauhvdL6BvmdFlZFny72xUN_-_peR4D1h25o1rT0FvE5Z1VZvrTAeu0OA/s400/Ocypodidae.jpg" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/crabs-ocypodidae-singapore.html">Ocypodid crabs (superfamily Ocypodoidea, family Ocypodidae)</a> typically have long eyestalks, but are usually not as long or as narrow as the ones found in the previous related family. The carapace may be squarish, rectangular or trapezoidal, and many species have a lobe at the front between the bases of the eyestalks. The chelipeds are usually unequal-sized, especially in the males of some species, whereby one cheliped is much larger than the other. Ocypodid crabs are usually found on sandy or muddy substrates, hiding in their burrows with trapped pockets of air when the tide is high, and emerge only during low tide to feed. Some species feed mainly on detritus, while other scavenge or actively hunt for prey.<br />
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<u><b>R) Silt Crabs (Family Camptandriidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhBdVt4t08BOqM-kbuSG4Z8JwWELb136Y72mOgB9Kl3lEdxZKhUYMc2W278qPwrQdY3IeRaqSfuNCtOUgs83j_g5WDwzJtlt_xHoVzIQc25VFkyubiEsp2yeOECMWKgGXdc3R2w7w/s1600/Paracleistostoma-depressum.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhBdVt4t08BOqM-kbuSG4Z8JwWELb136Y72mOgB9Kl3lEdxZKhUYMc2W278qPwrQdY3IeRaqSfuNCtOUgs83j_g5WDwzJtlt_xHoVzIQc25VFkyubiEsp2yeOECMWKgGXdc3R2w7w/s400/Paracleistostoma-depressum.jpg" width="400" /></a><br />
Silt crabs (superfamily Ocypodoidea, family Camptandriidae) typically have rounded to trapezoidal carapace and long eye stalks. The margins of the carapace are seldom broken by teeth or spines. The chelipeds are either equal or somewhat equal in shape and sizes, though the ones in males tend to be more swollen. Their first and last pair of walking legs tend to be shorter than the second and third pair. They are usually found on the mud, feeding on tiny decaying organic matter on the surface. I have only photographed one species in Singapore, the <b>Red Silt Crab (<i>Paracleistostoma depressum</i>)</b>. This small crab with a maximum carapace width of about 1.5cm has bright red claws. The trapezoidal carapace has a pale outline when viewed from the top.<br />
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<u><b>S) Dotillid Crabs (Family Dotillidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhd_27MK-ZDhxplONATAhhU4Xm4-qlIuN19I0d1F_P0iK7SfN7XS0v2njC-9JCzVw-OqIpIWXvWrLRNUYCVcZZGxMswyrnT15nOSbXo65Yweixjy7tR0y9y-5UDWDxTUu-3Vz04_g/s1600/Dotillidae.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhd_27MK-ZDhxplONATAhhU4Xm4-qlIuN19I0d1F_P0iK7SfN7XS0v2njC-9JCzVw-OqIpIWXvWrLRNUYCVcZZGxMswyrnT15nOSbXo65Yweixjy7tR0y9y-5UDWDxTUu-3Vz04_g/s400/Dotillidae.jpg" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/soldier-sandbubbler-crabs-dotillidae.html">Dotillid crabs (superfamily Ocypodoidea, Family Dotillidae)</a> are typically small crabs with rounded carapaces. The eyestalks are elongate, giving them a good view of the surrounding. They include the Sand Bubbler and Soldier Crabs that are usually found on sandy or muddy upper shores, hiding in their burrows during high tide, and emerge only during low tide to feed. Dotillid crabs are typical deposit feeders, meaning they feed on the detritus deposited on the substrate. They will put the sand into their mouthparts to extract the layer of detritus covering the sand grains, then push the cleansed sand grains out of the mouthparts where they will gather into a sand ball, and toss the sand ball aside when it gets too big. The numerous tiny sand balls found on sandy beaches are usually made by them.<br />
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<u><b>T) Porter Crabs (Family Dorippidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjqmx1ZOn4mLY6YRBEktB_rhPGz7b7ynLmgkFDNNWLWQ3kpHccHEw6jnFe-tT_Q7oZqhJmsiSA-2zM39UKKw8lx_Kwy6R7W9J55zMVtcy0ml9EhXgbXHzCFIhzpODeThqmRER36FA/s1600/Dorippidae.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjqmx1ZOn4mLY6YRBEktB_rhPGz7b7ynLmgkFDNNWLWQ3kpHccHEw6jnFe-tT_Q7oZqhJmsiSA-2zM39UKKw8lx_Kwy6R7W9J55zMVtcy0ml9EhXgbXHzCFIhzpODeThqmRER36FA/s400/Dorippidae.jpg" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/porter-crabs-dorippidae-singapore.html">Porter crabs (superfamily Dorippoidea, family Dorippidae)</a> are often not easy to spot on the seashore, as they usually camouflage themselves by carrying a leaf, broken shell or other small items on their back. Sometimes, they can also be seen swimming upside-down near the water surface, with the item they are carrying facing downwards, appearing just like a floating debris when viewed from below! Without the item they are carrying, they can be recognised by their last two pairs of legs, which are oriented upwards for carrying things instead of downwards for walking. The carapace is usually trapezoidal, with the front margin narrower than the rear margin, and longer than broad. They are mostly scavengers.<br />
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<u><b>U) Epialtid Spider Crabs (Family Epialtidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtw9sLp-7635-crm9NHGFI7NnowJeqtDD4w8uuGKzajsxlkaP3UKlnaodv9IdbhkBxE8RUXE3wQf_otvtqHVivlUTfF6y4KtZExTseKrNDTggdCeiS3iw0k63BPxI7x6ZpoKpUfA/s1600/Menaethius_monoceros.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtw9sLp-7635-crm9NHGFI7NnowJeqtDD4w8uuGKzajsxlkaP3UKlnaodv9IdbhkBxE8RUXE3wQf_otvtqHVivlUTfF6y4KtZExTseKrNDTggdCeiS3iw0k63BPxI7x6ZpoKpUfA/s400/Menaethius_monoceros.jpg" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/epialtidae-spider-crabs-singapore.html">Epialtid spider crabs (superfamily Majoidea, family Epialtidae)</a> typically have a triangular, longer than broad, flattish carapace, and the entire exoskeleton is mostly covered in hooked hairs (which helps to cling on to encrusting organisms or collect sediment for camouflage). The rostrum (nose-like tip at the front) is relatively huge and beak-like, and may be simple or two-spined. Epialtid spider crabs can usually be distinguished from other spider crabs (superfamily Majoidea) found on our shores by their very shot eyestalks and the lack of eyeholes (or orbits). However, this is not a very useful feature in the field as they are usually overgrown with algae or other encrusting organisms. The epialtid spider crabs that occur in Singapore waters are usually very small (not more than one or two cm long), and hence, the small size, relatively huge rostrum and elongate triangular shape are often more useful. These crabs feed mainly on marine algae or other plant materials.<br />
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<u><b>V) Inachid Spider Crabs (Family Inachidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZxVykEKg3lERmUdqT9BDFvivcEJ3J4yE2bx60LFX9gqZHxD9zJx5CGWkDHJ_x9SLT5S0HvVGrj-ENfAOdJqcaJztQibjW3ksAJRuimXyoSI9J0Y5o1cnoTPkIg3aphnCE6goEyg/s1600/Inachidae.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZxVykEKg3lERmUdqT9BDFvivcEJ3J4yE2bx60LFX9gqZHxD9zJx5CGWkDHJ_x9SLT5S0HvVGrj-ENfAOdJqcaJztQibjW3ksAJRuimXyoSI9J0Y5o1cnoTPkIg3aphnCE6goEyg/s400/Inachidae.jpg" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/velcro-crabs-inachidae-singapore.html">Inachid spider crabs (superfamily Majoidea, family Inachidae)</a> often have velcro-like hooked hairs on their exoskeleton, which helps to hold on to sponges, asidians and small bits of debris for camouflage purposes. The hooked hair is present in other spider crabs (superfamily Majoidea) though. They can be distinguished from other spider crabs by their visibly long eyestalks and the lack of obvious orbits (i.e. eyeholes). The carapace is triangular or teardrop-shaped, with a short rostrum that may come with a single spine. Studies suggest that they either scavenge or feed on small invertebrates. Unlike most other crabs, inachid spider crabs can move forward-backwards instead of just sideways.<br />
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<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/07/velcro-crabs-inachidae-singapore.html">>> more</a></span></div>
<u><b>W) True Spider Crabs (Family Majidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhOKC67OuuoDLhXzASFXOuTIieo2PQH6uP7psKffV-o7k8DjxfRojkAOS2PCe4SByjpHDj_3bOCKocUmS9q85VMgOZItPLBIhBv277HMNnWJ9f6TrwsJ0n7R3bUHWE2JjtXS2xVAg/s1600/Majidae.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhOKC67OuuoDLhXzASFXOuTIieo2PQH6uP7psKffV-o7k8DjxfRojkAOS2PCe4SByjpHDj_3bOCKocUmS9q85VMgOZItPLBIhBv277HMNnWJ9f6TrwsJ0n7R3bUHWE2JjtXS2xVAg/s400/Majidae.jpg" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/spider-crabs-majidae-singapore.html">True spider crabs (superfamily Majoidea, family Majidae)</a> can be distinguished from other spider crabs by having eyes with nearly complete or complete orbits. A pair of sharp spines can usually be found at the front near the eye, and sometimes the spines may bear smaller spinelets. The carapace is usually triangular or pear-shaped, often with spines by the sides. The entire exoskeleton is usually covered in hooked hairs which trap sediment and other sessile organisms such as ascidians and sponges, allowing it to blend into the surrounding. Unlike most other crabs, true spider crabs can move forward-backwards instead of just sideways. True spider crabs are usually scavengers, though some are known to actively hunt small invertebrates as well. Some of the smaller species can be mistaken for sponge crabs (see below). Spider crabs, however, attached the sessile organisms to the hooked hairs on their backs, unlike the sponge crabs which carry them using their rear legs.<br />
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<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/07/spider-crabs-majidae-singapore.html">>> more</a></span></div>
<u><b>X) Sponge Crabs (Family Dromiidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXp-tUGlQhEpvmhdmeiCZKdvLeIvEooDUfWZNTrrT_cITa6ZN2OK_7GzUiMrzTRbBg6YED7ysduGKNPUDdYXdiJqglJvtRsECaDr95KXA9vet3Fw-zd3XJMI0-631jbsMT3hSH4w/s1600/Dromiidae.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXp-tUGlQhEpvmhdmeiCZKdvLeIvEooDUfWZNTrrT_cITa6ZN2OK_7GzUiMrzTRbBg6YED7ysduGKNPUDdYXdiJqglJvtRsECaDr95KXA9vet3Fw-zd3XJMI0-631jbsMT3hSH4w/s400/Dromiidae.jpg" width="400" /></a><br />
<a href="http://tidechaser.blogspot.sg/2013/07/sponge-crabs-dromiidae-singapore.html">Sponge crabs (superfamily Dromioidea, family Dromiidae)</a> are so-named for their habit of carrying a piece of living sponge or colonial ascidian for camouflage purposes. Some sponge crabs may be mistaken for spider crabs, but their method of carrying the ascidians and sponges are different. Sponge crabs carry the ascidians or sponges with their last two pairs of legs. These legs are inserted obliquely on the circular to hexagonal carapace, directed upwards. Hence, sponge crabs only use two pair of legs for walking. Spider crabs, on the other hand, stick the ascidians or sponges to the hooked hairs on their exoskeletons, and use all four pairs of legs for walking. They are mostly scavengers.<br />
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<span style="font-size: x-small;"><a href="http://tidechaser.blogspot.sg/2013/07/sponge-crabs-dromiidae-singapore.html">>> more</a></span></div>
<u><b>Y) Pebble Crabs (Family Leucosiidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7AeHI4ItKg3hcaihPKAaUhs14xmb4nuQLWemsPRWZO1a30__g7Ve1y_se142n1tZObxymFl1RnH-SG1RuFYPgl_1mEDhnrPAtCAheLLi6SnhjjKsgRBbma_SHve48WpOBpKC5jA/s1600/Leucosiidae.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7AeHI4ItKg3hcaihPKAaUhs14xmb4nuQLWemsPRWZO1a30__g7Ve1y_se142n1tZObxymFl1RnH-SG1RuFYPgl_1mEDhnrPAtCAheLLi6SnhjjKsgRBbma_SHve48WpOBpKC5jA/s400/Leucosiidae.jpg" width="400" /></a><br />
<b>Pebble crabs (superfamily Leucosioidea, family Leucosiidae)</b> usually have circular, oval or pentagonal carapaces. Many species have a convex carapace, and appear much like round pebbles, and hence the common name. The eyes and antennae are very tiny and hardly noticeable, and the chelipeds are symmetrical. Most pebble crabs are adapted for burrowing, and are found in soft substrates like sand or mud. Many species feed on tiny invertebrates by probing the top layer of the sediment and capturing the ones disturbed. So far, I have not been able to identify the pebble crabs that I have seen yet. Apart from the one above, I have also seen <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFilB-yuSv5nHAifIjx9IZfKa4gEnB3H86Rro74rg6mJyKmMZys4yHsoRqEqxlzTvSl9f_T4caJTbUfhwR5I7pq2_rqdncIg2TWHadURqOoAxalo43AJEiQrYbqFj7BXrccXY9ng/s1600/Leucosiidae.jpg">another one with a more reddish brown tint</a>.<br />
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<u><b>Z) Masked Crabs (Family Corystidae)</b></u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEizjPJws8lxZBwOW9QykWPXDp4MCsR3I7NCEev3pTBz81BZCB-20o8puoRW4rHkBFQLDXHQx1RozQtgihcVleNmt_7ccWmGgJFzmqXW8oMC2y53gKOdE3EgFVllSXy_o_Xd9jR-tw/s1600/Gomeza-bicornis.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEizjPJws8lxZBwOW9QykWPXDp4MCsR3I7NCEev3pTBz81BZCB-20o8puoRW4rHkBFQLDXHQx1RozQtgihcVleNmt_7ccWmGgJFzmqXW8oMC2y53gKOdE3EgFVllSXy_o_Xd9jR-tw/s400/Gomeza-bicornis.jpg" width="400" /></a><br />
<b>Masked crabs (superfamily Corystoidea, family Corystidae)</b> can usually be recognised by their long and hairy antennae, which can be as long as or longer than their body. The carapace is ovate or somewhat circular, usually longer than broad. Most species are good burrowers, and are found on soft substrates such as sand or mud. They are called masked crabs due to <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKsZnm7iI29nWxZSV5AxHQU-hSDwe3iI7Xu03FVjpFGqMOOghYSNxWPTxMkVGnfMiiTvLrVeyKIOo6eKfN-cyeCGgaHxHW_XfSR5_WMXrs56HDYHQrwmitHkrJ2_OUSF1rcFBPmw/s1600/Gomeza_bicornis.jpg">the shape of their carapaces and the patterns on them</a>, which somewhat resemble human faces. They usually feed on small invertebrates in the sediment. So far I have only seen one species in Singapore, and it was tentatively identified as the <b>Masked Burrowing Crab (<i>Gomeza bicornis</i>)</b>.<br />
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<b>References</b><br />
<ul style="text-align: left;">
<li>Burnie, D. 2001. <i>Animal</i>. London: Dorling Kindersley. 624 pp.</li>
<li>Carpenter, K. E. & V. H. Niem (eds), 1998-2001. <i>FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific</i>. Volumes 1 to 6. FAO, Rome. pp. 1-4218.</li>
<li>Castro, P., P. K L. Ng & S. T. Ahyong. 2004. Phylogeny and systematics of the Trapeziidae Miers, 1886 (Crustacea: Brachyura), with the description of a new family. <i>Zootaxa </i>643:1–70.</li>
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>Debelius, H. 1999. <i>Crustacea - Guide of the world</i>. IKAN, Frankfurt. 321pp.</li>
<li>ETI BioInformatics. 2012. <i>Marine species identification portal</i>. Retrieved Jul 8, 2013, from http://species-identification.org.</li>
<li>Mendoza, J. C. E. & P. K. L. Ng, 2007. Macrophthalmus (Euplax) H. Milne Edwards, 1852, a valid subgenus of ocypodoid crab (Decapoda: Brachyura: Macrophthalmidae), with description of a new species from the Philippines. <i>Journal of Crustacean Biology</i>, 27(4): 670–680.</li>
<li>Ng, P. K. L., L. K. Wang & K. K. P. Lim (eds.). 2008. <i>Private lives: An exposé of Singapore’s mangroves</i>. Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 240 pp.</li>
<li>Ng, P. K. L. & N. Sivasothi (eds.), 1999. <i>A guide to the mangroves of Singapore II: animal diversity</i>. Singapore Science Centre. 168p.</li>
<li>Ng, P. K. L., S. S. L. Lim, L. K. Wang & L. W. H. Tan. 2007. <i>Private lives: An exposé of Singapore's shores</i>. Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 212 pp.</li>
<li>Ng, P. K .L., R. T. Corlett & H.T.W. Tan (eds.). 2011. <i>Singapore biodiversity: An encyclopedia of the natural environment and sustainable development</i>. Singapore: Editions Didier Millet. 552 pp.</li>
<li>Štev cic , Z., 1983. Revision of the Calappidae. <i>Memoirs of the Australian Museum</i>, 18: 165–172.</li>
<li>Tan, L. W. H. & P. K. L. Ng. 1988. <i>A Guide to Seashore Life</i>. Singapore Science Centre. Singapore. 160 pp.</li>
<li>Tan, S. H. 2004. A Systematic Revision of the Parthenopidae(Crustacea: Decapoda: Brachyura). Unpublished PhD Thesis, National University of Singapore. 729 pp.</li>
<li>Vasconcelos M. A., T. C. Mendes, W. L. S. Fortes& R. C. Pereira. 2009. Feeding and decoration preferences of the Epialtidae Crab Acanthonix scutiforms. <i>Brazilian Journal of Oceanography</i>, 57: 137-143.</li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
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Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com2tag:blogger.com,1999:blog-9797239.post-52587117467907639952013-07-26T17:41:00.000+08:002013-07-26T18:04:28.214+08:00Freshwater Crabs & Shrimps of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
Several species of freshwater crabs and shrimps are recorded from Singapore, with the native species being found mostly in clear forest streams, and the introduced species in reservoirs and ponds.<br />
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Crabs and shrimps are of the order Decapoda, and like other members of this order, they have five pairs of "legs", including the clawed arms ("deca" means "ten", while "poda" means "feet"). They also have leaf-like gills, a distinctive characteristic of decapods from the suborder Pleocyemata. And as with other crustaceans from the class Malacostraca, their body comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head is fused with the thorax to form a cephalothorax. They have a tough exoskeleton strengthened with calcium carbonate, and the carapace covers the gills but not the abdomen.<br />
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Crabs (infraorder Brachyura) can be distinguished from other similar-looking decapods by having a broad carapace, a very short and flattened abdomen which is usually folded underneath the body, a pair of clawed arms, and four pairs of walking legs. Sometimes, one or more pairs of legs may be modified for swimming or other purposes. Their antennae are relatively short, and their eyes are on stalks.<br />
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The shrimps found in our freshwater environments are caridean shrimps (infraorder Caridea). They have an elongate abdomen bearing five pairs of swimming appendages (or pleopods) and ending off with a tail fan. The tail fan comprises a pointed, tail-like structure (or telson) in the middle and a pair of flattened appendages (or uropods) by the sides. The pleopods are used for brooding the eggs and for swimming, while the uropods are used for steering while swimming. They can be distinguished from the similar-looking prawns (suborder Dendrobranchiata) by the lack of pincers at the tips of their third pair of walking legs. Also, the "shell" of the second abdominal segment is enlarged, overlapping and covering part of the first segment and the third segment. Internally, caridean shrimps have gills that are leaf-like, while prawns have gills that are branch-like.<br />
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Crabs and shrimps reproduce sexually, and have separate sexes. Unlike penaeid prawns that release their eggs into the water, they brood their eggs under their abdomen until they hatch.<br />
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Here are some of the freshwater crabs and shrimps that I have photographed in Singapore. The marine crabs and shrimps will be treated in separate entries.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1dQtBQ9lzzM0C_rB3LWrriQuDdmWx_wPRyrlxM9yysSnqo2Kk7UElgXFV8sINvhtH_oCpcMwVBBg_RjE1AgkaAVgepYjOUrgt-hr86lFVWrwD4TENms6PA8tNFAnjVvyN_cp4Vg/s1600/Johora-singaporensis.jpg"><img alt="Singapore Freshwater Crab (Johora singaporensis)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1dQtBQ9lzzM0C_rB3LWrriQuDdmWx_wPRyrlxM9yysSnqo2Kk7UElgXFV8sINvhtH_oCpcMwVBBg_RjE1AgkaAVgepYjOUrgt-hr86lFVWrwD4TENms6PA8tNFAnjVvyN_cp4Vg/s400/Johora-singaporensis.jpg" title="Singapore Freshwater Crab (Johora singaporensis)" width="400" /></a><br />
The <b>Singapore Freshwater Crab (<i>Johora singaporensis</i>)</b> is one of the rarest animals in the world, and was in fact listed recently as the top 100 most threatened species in the world during the International Union for the Conservation of Nature's World Conservation Congress. Its colour varies from a dirty brown to purplish brown, with the big ones being more purplish. It can be distinguished from other native brownish freshwater crabs by the fine and stiff hair covering its carapace and legs. The carapace usually does not get more than 3cm wide. This species was previously confused with other crab species, and was only discovered to be a separate species in 1986! It is endemic to Singapore (i.e. not found any where else in the world).<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjSWHd-ALXDXTWOe2MOgK5WG9t_xzdzniQIbqoUG6sfVolMrH0mQHdWFrQ7oS0qD-Mq5YCfQ3_57uxKivnLPVay7ZmgnCYkq_jPu8-cLp1SferKwj-BoMvQ2dLSKpQSEOCarJ3B3g/s1600/Johora-singaporensis.jpg"><img alt="Singapore Freshwater Crab (Johora singaporensis)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjSWHd-ALXDXTWOe2MOgK5WG9t_xzdzniQIbqoUG6sfVolMrH0mQHdWFrQ7oS0qD-Mq5YCfQ3_57uxKivnLPVay7ZmgnCYkq_jPu8-cLp1SferKwj-BoMvQ2dLSKpQSEOCarJ3B3g/s400/Johora-singaporensis.jpg" title="Singapore Freshwater Crab (Johora singaporensis)" width="400" /></a><br />
The above is a smaller specimen that is more uniformly brownish in colour. The carapace of the Singapore Freshwater Crab is somewhat trapezoidal with rounded corners. This species usually occurs in clear, clean water, oxygen-rich and fast-flowing forest streams, usually at higher elevations. <br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiZJQRqMGivMirCAzIVaACHKHTVwkVVUT0zIFHv4VeY0VTERjkQ9x1RRuWjeiPGnj8S-nPyDYTa5XKmR4CS72zZM_iRCaW53hLTOURjQs5QQ_erl9F4TLYZZUVSlKS_72lkxUv1cA/s1600/Johora_singaporensis.jpg"><img alt="Singapore Freshwater Crab (Johora singaporensis)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiZJQRqMGivMirCAzIVaACHKHTVwkVVUT0zIFHv4VeY0VTERjkQ9x1RRuWjeiPGnj8S-nPyDYTa5XKmR4CS72zZM_iRCaW53hLTOURjQs5QQ_erl9F4TLYZZUVSlKS_72lkxUv1cA/s400/Johora_singaporensis.jpg" title="Singapore Freshwater Crab (Johora singaporensis)" width="400" /></a><br />
Bigger specimens tend to have pale bands on the legs, purplish-red pincers, and a generally more purplish overall coloration. Singapore Freshwater Crabs feed on plant materials and small invertebrates. They are usually found under the leaf litter or rocks.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioXkQ22fF1p4Wtav4FUeK1dZTdF0PEUTxvlPjYr7Erf_-K5TG5VMTOriKok1r7h474_O16sRQa_T6t8lrsYvNLvfcY1vmeK4iZwNSPbkNTaSTjeYHRCl93zmrwCYh2Iftih_0vqA/s1600/Irmengardia-johnsoni1.jpg"><img alt="Johnson's Freshwater Crab (Irmengardia johnsoni)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioXkQ22fF1p4Wtav4FUeK1dZTdF0PEUTxvlPjYr7Erf_-K5TG5VMTOriKok1r7h474_O16sRQa_T6t8lrsYvNLvfcY1vmeK4iZwNSPbkNTaSTjeYHRCl93zmrwCYh2Iftih_0vqA/s400/Irmengardia-johnsoni1.jpg" title="Johnson's Freshwater Crab (Irmengardia johnsoni)" width="400" /></a><br />
The <b>Johnson's Freshwater Crab (<i>Irmengardia johnsoni</i>)</b> can sometimes be confused with the previous species due to its brownish coloration, but it lacks the numerous fine hairs covering the body of the latter. This species is endemic to Singapore (i.e. not found any where else in the world), and was only identified as a new species in 1985.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_o6dSTK747HpIw5A36Y-_bCSRYbfIsUEqGQ0PpYqkM229mqXDhf6nB2dqB1AIVAEU5txxoKm34nHI_FcF1dTftGl4z26R5HlXehT85bSB_nXAftkyPWSKce30NpS1MTWTbmlaFQ/s1600/Irmengardia-johnsoni.jpg"><img alt="Johnson's Freshwater Crab (Irmengardia johnsoni)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_o6dSTK747HpIw5A36Y-_bCSRYbfIsUEqGQ0PpYqkM229mqXDhf6nB2dqB1AIVAEU5txxoKm34nHI_FcF1dTftGl4z26R5HlXehT85bSB_nXAftkyPWSKce30NpS1MTWTbmlaFQ/s400/Irmengardia-johnsoni.jpg" title="Johnson's Freshwater Crab (Irmengardia johnsoni)" width="400" /></a><br />
The carapace can get to about 3cm wide, and is often marked with dark brown botches or speckles.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTBfMageu1UD78DS2pZXf4dePJAcmwwk9L21QGEoKSdnthb6CK1Q1R3MUpgK52fW-qvmhozVCAM0D1k7aBln1yvSs2Kkp5w_Cl5O73aJiFpoTzVRHz94oe2H-BHC45o16i0W-7Nw/s1600/Irmengardia_johnsoni.jpg"><img alt="Johnson's Freshwater Crab (Irmengardia johnsoni)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTBfMageu1UD78DS2pZXf4dePJAcmwwk9L21QGEoKSdnthb6CK1Q1R3MUpgK52fW-qvmhozVCAM0D1k7aBln1yvSs2Kkp5w_Cl5O73aJiFpoTzVRHz94oe2H-BHC45o16i0W-7Nw/s400/Irmengardia_johnsoni.jpg" title="Johnson's Freshwater Crab (Irmengardia johnsoni)" width="400" /></a><br />
It is usually found at slower parts of shaded streams, and sometimes, at the edges of reservoirs. Its diet comprises dead leaves and freshwater invertebrates.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjyvGIhjym4_SjIg77CporZ2xhGJB23BD3tEov8h2hw9zmkN_2A2XHDBJOwNDeTw8boJPYiSGNomxEenzqoicyMyBPLj0UPz-c9tIdYxPRttSXohTiTirS80kakI2hhLAt1sVrW5w/s1600/Parathelphusa_maculata.jpg"><img alt="Maculate Freshwater Crab (Parathelphusa maculata)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjyvGIhjym4_SjIg77CporZ2xhGJB23BD3tEov8h2hw9zmkN_2A2XHDBJOwNDeTw8boJPYiSGNomxEenzqoicyMyBPLj0UPz-c9tIdYxPRttSXohTiTirS80kakI2hhLAt1sVrW5w/s400/Parathelphusa_maculata.jpg" title="Maculate Freshwater Crab (Parathelphusa maculata)" width="400" /></a><br />
The <b>Maculate Freshwater Crab (<i>Parathelphusa maculata</i>)</b> or Lowland Freshwater Crab is usually found in lowland streams. It appears to be able to tolerate low oxygen conditions, and hence is found in stagnant pools sometimes. This species is known to dig deep burrows up to 1m deep at the banks of the stream. The burrow opening is usually above the water level, but the lower part is usually filled with water.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6QUeo1xzIlrhEKABwBVw-SNO0N-8KUhj0T3e5w-2LQkDH8E_3VHxfCfabTvkjpEZJdjqYalpF99xg1zLYFFsdZMti1Kx8naKlGzTKN5IGKtiwAjfPLHWPFUQZfVLBAsa4wS0OHA/s1600/Parathelphusa-maculata.jpg"><img alt="Maculate Freshwater Crab (Parathelphusa maculata)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6QUeo1xzIlrhEKABwBVw-SNO0N-8KUhj0T3e5w-2LQkDH8E_3VHxfCfabTvkjpEZJdjqYalpF99xg1zLYFFsdZMti1Kx8naKlGzTKN5IGKtiwAjfPLHWPFUQZfVLBAsa4wS0OHA/s400/Parathelphusa-maculata.jpg" title="Maculate Freshwater Crab (Parathelphusa maculata)" width="400" /></a><br />
The colour varies from light brown with spots and speckles to dark brown. They are known to feed on both plant materials and small animals.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0RPKUu_xEjT1OSlI6Vx8BkZkeWVtw4yfRVU7-gdyKuV-DXy49a_FqCuo6vMyqpsPUSEY-LdSTnc66EhhuVc3oogeTCh28gE7_cQ4LW18dMsm6chSz9xjS0PHCKlYWsuBBPQ7_bA/s1600/Parathelphusa-maculata-closeup.jpg"><img alt="Maculate Freshwater Crab (Parathelphusa maculata)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0RPKUu_xEjT1OSlI6Vx8BkZkeWVtw4yfRVU7-gdyKuV-DXy49a_FqCuo6vMyqpsPUSEY-LdSTnc66EhhuVc3oogeTCh28gE7_cQ4LW18dMsm6chSz9xjS0PHCKlYWsuBBPQ7_bA/s400/Parathelphusa-maculata-closeup.jpg" title="Maculate Freshwater Crab (Parathelphusa maculata)" width="400" /></a><br />
It can be distinguished from the previous two species by the two sharp spines at the two front corners of the carapace. Apart from the Maculate Freshwater Crab, another <i>Parathelphusa </i>species, <i>P. reticulata</i>, can also be found in Singapore. This species is not featured here as I still do not have photos of it. It is endemic to Singapore, and has dark, honeycomb patterns on its back.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjEO6XXAh5exhM8ns4IWNfS28ImYOgFLdmAL1Y-5FrxQub_D84CwfzQgdPpRpkQRtoqwVyqQ-fN-Tl-WOlqNUn8u_GqyNhtvxfnXUNP81B2F7ldP-_-jI2K3zU002fE9y1Mpytt4A/s1600/Geosesarma-nemesis.jpg"><img alt="Little Land Crab (Geosesarma nemesis)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjEO6XXAh5exhM8ns4IWNfS28ImYOgFLdmAL1Y-5FrxQub_D84CwfzQgdPpRpkQRtoqwVyqQ-fN-Tl-WOlqNUn8u_GqyNhtvxfnXUNP81B2F7ldP-_-jI2K3zU002fE9y1Mpytt4A/s400/Geosesarma-nemesis.jpg" title="Little Land Crab (Geosesarma nemesis)" width="400" /></a><br />
Two <i>Geosesarma </i>species occur in Singapore, and the above is a <b>Little Land Crab (<i>Geosesarma nemesis</i>)</b>. It can be distinguished from the other species (<i>G. perracae</i> that is not featured here) by its squarish carapace (the latter has a trapezoidal carapace). The maximum carapace width is about 1.5cm. The color ranges from bright red to brownish. It is mostly a scavenger.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj4DU8MeN2rdq3ZclhRIKtrqI38Furj2pD0ZA7qnSVpvAqifCJLyB88CpKJO_uyPaQKTRR7fxCcZZkTNcNTfxmCakeqRNUf8GKBSFdejVr-WQwf5Etk1FAaOhZC_mc61XO8X5uGHA/s1600/Geosesarma-nemesis-female.jpg"><img alt="Little Land Crab (Geosesarma nemesis)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj4DU8MeN2rdq3ZclhRIKtrqI38Furj2pD0ZA7qnSVpvAqifCJLyB88CpKJO_uyPaQKTRR7fxCcZZkTNcNTfxmCakeqRNUf8GKBSFdejVr-WQwf5Etk1FAaOhZC_mc61XO8X5uGHA/s400/Geosesarma-nemesis-female.jpg" title="Little Land Crab (Geosesarma nemesis)" width="400" /></a><br />
The Little Land Crab is mostly terrestrial, and is known to burrow under rocks near the stream. This species prefer highlands, unlike the other local land crab which prefers lowland areas. The above features a female with smaller claws.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijloEo65wpANPqG_ivzlJXJqEG4b_SQvbCco7hlFGxTlrozrZ-DScVkKPZbfFk9iDaBt27iLNfBQg4359bVwW1Kg9mpU5RCWSyr61nE-bfSmw6mUPDWvOVV7zoyP6DjdwkWk-Dzw/s1600/Geosesarma-nemesis-male.jpg"><img alt="Little Land Crab (Geosesarma nemesis)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijloEo65wpANPqG_ivzlJXJqEG4b_SQvbCco7hlFGxTlrozrZ-DScVkKPZbfFk9iDaBt27iLNfBQg4359bVwW1Kg9mpU5RCWSyr61nE-bfSmw6mUPDWvOVV7zoyP6DjdwkWk-Dzw/s400/Geosesarma-nemesis-male.jpg" title="Little Land Crab (Geosesarma nemesis)" width="400" /></a><br />
The male Little Land Crab has a pair of larger chelipeds. It can be distinguished from <i>G. perracae</i> by the lacking of a wide gap between the fingers of the pincers.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEilQiN6kq2_aUr5hwIYjYw_FFPc1Gnm-3xXAuVKBibuuSc34T43uIj9Ol_If9lrNvredqoj8w3sTcnW8uA1wzMb3cRnyVX-PBh9GBY46GUPD1EjD50sQHXUg19I9455Z1JUJ-df_w/s1600/Macrobrachium.jpg"><img alt="Macrobrachium sp." border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEilQiN6kq2_aUr5hwIYjYw_FFPc1Gnm-3xXAuVKBibuuSc34T43uIj9Ol_If9lrNvredqoj8w3sTcnW8uA1wzMb3cRnyVX-PBh9GBY46GUPD1EjD50sQHXUg19I9455Z1JUJ-df_w/s400/Macrobrachium.jpg" title="Macrobrachium sp." width="400" /></a><br />
Several species of freshwater shrimps occur in Singapore, and the most easily seen ones are the <i>Macrobrachium </i>shrimps (<i>Macrobrachium</i> spp.) They usually have a pair of much enlarged claws. The above photo features an unidentified species. The above <i>Macrobrachium </i>shrimp is found in a clear, fast-flowing, hill-side forest stream. It si about 5cm long.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhtcBSXsjxid3AesHCF6DrcvXXo_-FwhgLtCvnOasKSLtWWQobBgC7iLtRDMB9WEnZjV2devpgdmLsktz3benOoc8rZdp2DRXodDlD1rYQLk4lBnlqfOuTXgCeRumrghnIzy6aMig/s1600/Macrobrachium1.jpg"><img alt="Macrobrachium sp." border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhtcBSXsjxid3AesHCF6DrcvXXo_-FwhgLtCvnOasKSLtWWQobBgC7iLtRDMB9WEnZjV2devpgdmLsktz3benOoc8rZdp2DRXodDlD1rYQLk4lBnlqfOuTXgCeRumrghnIzy6aMig/s400/Macrobrachium1.jpg" title="Macrobrachium sp." width="400" /></a><br />
<i>Macrobrachium </i>shrimps are usually hard to identify unless they are caught and examine carefully. And hence I will not attempt to identify them here. The above is another example of a <i>Macrobrachium </i>shrimp. It is found in a clear, fast flowing, hill-side forest stream. It is about 5cm long.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj4JS48iKnOvi_9KS8RgLVGJrIGOvDnsGp1hSz2ThbaZW4hDHfjNAU-fy2-ekzC3-x6zJGuICF4VyDO_8eYomWOh9Hg7pdo1E_XcUjmOxnj6tf2R2B3LUN8XeEYS04oiKvyc2h3fw/s1600/Macrobrachium2.jpg"><img alt="Macrobrachium sp." border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj4JS48iKnOvi_9KS8RgLVGJrIGOvDnsGp1hSz2ThbaZW4hDHfjNAU-fy2-ekzC3-x6zJGuICF4VyDO_8eYomWOh9Hg7pdo1E_XcUjmOxnj6tf2R2B3LUN8XeEYS04oiKvyc2h3fw/s400/Macrobrachium2.jpg" title="Macrobrachium sp." width="400" /></a><br />
The above <i>Macrobrachium </i>species is found on a wide and slower-flowing, lowland forest stream. It is about 4cm long.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEid4TSpCBR_VNPsDSAgw7vDuPYVpGuJ1KimBjkaSlWBecmuoiT09n65awWqg8oKzjtBIfaxJfKBlygTgbUPAgZCXUk4QXCS9w8ZuMNs-8UQFRKzGpU-WyPPIbItVI-xdXIaTgVOVQ/s1600/Macrobrachium-nipponense.jpg"><img alt="Oriental River Prawn (Macrobrachium nipponense)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEid4TSpCBR_VNPsDSAgw7vDuPYVpGuJ1KimBjkaSlWBecmuoiT09n65awWqg8oKzjtBIfaxJfKBlygTgbUPAgZCXUk4QXCS9w8ZuMNs-8UQFRKzGpU-WyPPIbItVI-xdXIaTgVOVQ/s400/Macrobrachium-nipponense.jpg" title="Oriental River Prawn (Macrobrachium nipponense)" width="400" /></a><br />
The <b>Oriental River Prawn (<i>Macrobrachium nipponense</i>)</b> has been introduced into some of our reservoirs, and the mature ones can be recognised by the long and large claws. It is native to East Asia, and grows to about 8cm long (excluding the claws).<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0xT3orgzvQFoQipN0EVQn6PkHFiFDy_uQVQiqgsq_cR62ahqiaqaVP89lKeLjdByzVZNsrM-EtGJSVWiw7w7MAMk1iL1KUbmuzPlCvrfPb579A5Ld_1lyUlQOfisI8qzkfYwEdA/s1600/Cherax-quadricarinatus.jpg"><img alt="Redclaw Crayfish (Cherax quadricarinatus)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0xT3orgzvQFoQipN0EVQn6PkHFiFDy_uQVQiqgsq_cR62ahqiaqaVP89lKeLjdByzVZNsrM-EtGJSVWiw7w7MAMk1iL1KUbmuzPlCvrfPb579A5Ld_1lyUlQOfisI8qzkfYwEdA/s400/Cherax-quadricarinatus.jpg" title="Redclaw Crayfish (Cherax quadricarinatus)" width="400" /></a><br />
The <b>Redclaw Crayfish (<i>Cherax quadricarinatus</i>)</b> is possibly introduced by irresponsible pet owners into several of our reservoirs and ponds. It is easily recognised by its bluish coloration. This species is native to Australia, and can grow to about 25cm long (excluding the claws)<br />
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<b>References</b><br />
<ul style="text-align: left;">
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>Debelius, H. 1999. <i>Crustacea - Guide of the world</i>. IKAN, Frankfurt. 321pp.</li>
<li>Ng, P. K. L. 1988. <i>The freshwater crabs of Peninsular Malaysia and Singapore</i>. Shinglee Press. Singapore. vii + 156. pp. 4. color pls.</li>
<li>Ng, P. K .L., R. T. Corlett & H.T.W. Tan (eds.). 2011. <i>Singapore biodiversity: An encyclopedia of the natural environment and sustainable development</i>. Singapore: Editions Didier Millet. 552 pp.</li>
<li>Yeo, D C. J. 2010. Introduced decapod crustaceans in Singapore's reservoirs, <i>Cosmos </i>6(1): 83-88 </li>
<li>Yeo, D. C. J., L. K. Wang & K. K. P. Lim (eds..) 2010. <i>Private lives: An exposé of Singapore's freshwaters</i>. Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 258 pp.</li>
</ul>
</div>
Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com0tag:blogger.com,1999:blog-9797239.post-58009558834634740462013-07-26T17:40:00.000+08:002013-07-26T18:04:28.219+08:00Box Crabs (Phylum Arthropoda: Family Calappidae) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
Box crabs (phylum Arthropoda, subphylum Crustacea, class Malacostraca, order Decapoda, suborder Pleocyemata, infraorder Brachyura, superfamily Calappoidea, family Calappidae) got their common name from their box-like appearances (with some imagination). They can be recognised by the somewhat rounded or oval carapace, the relatively narrow gap between the eye, and the laterally compressed chelipeds (which are usually held close to their mouthparts).<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhB4RZBbmDUiGkNHya_iSUqTFfs10QjfHcXkFIcGFTbh42oriQj_8K5Ohv3pXrRUdVE12ur9TH9QFDzr0QhtmHFxREIdLsNtqhA9_lAcn7qMUxL_8f5h7fFpd1xgkz3ejNVeEdjQw/s1600/Calappidae.jpg"><img alt="Box crabs (superfamily Calappoidea, family Calappidae)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhB4RZBbmDUiGkNHya_iSUqTFfs10QjfHcXkFIcGFTbh42oriQj_8K5Ohv3pXrRUdVE12ur9TH9QFDzr0QhtmHFxREIdLsNtqhA9_lAcn7qMUxL_8f5h7fFpd1xgkz3ejNVeEdjQw/s400/Calappidae.jpg" title="Box crabs (superfamily Calappoidea, family Calappidae)" width="400" /></a><br />
Box crabs have asymmetrical chelipeds. The right pincer has a curved tooth near the base of the upper finger, which the crab will stick into the opening of a snail, and use it much like a can-opening to cut a channel around the opening. The left pincer, which is more slender with forcep-like fingers, will then be used to extract the exposed snail from its shell.<br />
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Like other true crabs, box crabs have a broad carapace, and a very short and flattened abdomen which is usually folded underneath the body. They also have five pairs of "legs" (including the clawed arms), and hence they are placed in the order Decapoda ("deca" means "ten", while "poda" means "feet"). The gills are leaf-like - a distinctive characteristic of decapods from the suborder Pleocyemata. And as with other crustaceans from the class Malacostraca, their body comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head is fused to the thorax, forming a cephalothorax. They have a tough exoskeleton strengthened with calcium carbonate, and the carapace covers the gills but not the abdomen.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjdLDs0gFnVIc1HMXrbuCqNN_qJG_13vPTNmsViUITStspKQVhwiuSbA25VkjUGHlFO5QklLZ5QXcs56TVhyW15hJKYRoqbxtq0LjzuMok1dblH9LY0mcNh956nLkltXeIq4zhadA/s1600/Calappa_philargius.jpg"><img alt="Spectacled Box Crab (Calappa philargius)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjdLDs0gFnVIc1HMXrbuCqNN_qJG_13vPTNmsViUITStspKQVhwiuSbA25VkjUGHlFO5QklLZ5QXcs56TVhyW15hJKYRoqbxtq0LjzuMok1dblH9LY0mcNh956nLkltXeIq4zhadA/s400/Calappa_philargius.jpg" title="Spectacled Box Crab (Calappa philargius)" width="400" /></a><br />
Most box crabs are good burrowers, and are found on sandy to muddy substrates. The bigger ones are often collected for food by the locals but seldom sold in market due to the limited numbers caught.<br />
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They reproduce sexually, and have separate sexes. The females can usually be distinguished from the males by having a broader abdomen. This is an adaptation to allow them to carry the eggs under the abdomen until they hatch.<br />
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Here are some of the box crabs that can be seen Singapore.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj1eTHcqEFCPjH3RDUE5ezkgHdvp94ENC9MNHWjlPadBCpIJCiWogL3Md5Ol5K2mhCE_lrncjPaHlPXsb2RPa4FykazySF9QB9pAyI8lfdnh9uf8GGCUtrROxaN5eGI0DnuR-oyQA/s1600/Calappa-philargius.jpg"><img alt="Spectacled Box Crab (Calappa philargius)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj1eTHcqEFCPjH3RDUE5ezkgHdvp94ENC9MNHWjlPadBCpIJCiWogL3Md5Ol5K2mhCE_lrncjPaHlPXsb2RPa4FykazySF9QB9pAyI8lfdnh9uf8GGCUtrROxaN5eGI0DnuR-oyQA/s400/Calappa-philargius.jpg" title="Spectacled Box Crab (Calappa philargius)" width="400" /></a><br />
The <b>Spectacled Box Crab (<i>Calappa philargius</i>)</b> is usually found in sandy to slightly muddy substrates. It can be recognised by the two dark spots on each chelipad, and the dark patch around each eye (which gives it its common name).<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg8vL5iZntQFCLAUWLC74Xjm1Y0JXlbK2KZOvXIcPNFqkp_rykhJ1mCWUmXLy3mcrcouRYbX-1usnsSS6PyvDqrO-eoCJfONKYol_J-94Xr5SxFLPgxN9GJ2NwcwOgiFBnKOr99KQ/s1600/Calappa_philargius.jpg"><img alt="Spectacled Box Crab (Calappa philargius)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg8vL5iZntQFCLAUWLC74Xjm1Y0JXlbK2KZOvXIcPNFqkp_rykhJ1mCWUmXLy3mcrcouRYbX-1usnsSS6PyvDqrO-eoCJfONKYol_J-94Xr5SxFLPgxN9GJ2NwcwOgiFBnKOr99KQ/s400/Calappa_philargius.jpg" title="Spectacled Box Crab (Calappa philargius)" width="400" /></a><br />
It is usually of a light orangy-brown colour, and the back margin of the carapace is lined with spines. Dark markings can be seen on the inner sides of the chelipeds. The Spectacled Box Crab can grow to about 12cm broad (carapace only). It is often collected for food, but is rarely sold in the market.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQulDDt2W-e8iElfoC_iWSvVTgymSh1_0iQ0fzOgjm6EWLJurIO_i1Q8ht1GJ5ccTz159tMS4yKQ0Q3CvSqpMd55IGHWsc__foL_ffj4h8Wyi1NIQjkDvyTb6mWM5hn4YaBW7q9Q/s1600/Calappa-hepatica.jpg"><img alt="Reef Box Crab (Calappa hepatica)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQulDDt2W-e8iElfoC_iWSvVTgymSh1_0iQ0fzOgjm6EWLJurIO_i1Q8ht1GJ5ccTz159tMS4yKQ0Q3CvSqpMd55IGHWsc__foL_ffj4h8Wyi1NIQjkDvyTb6mWM5hn4YaBW7q9Q/s400/Calappa-hepatica.jpg" title="Reef Box Crab (Calappa hepatica)" width="400" /></a><br />
The <b>Reef Box Crab (<i>Calappa hepatica</i>)</b> is sometimes seen on sandy and shelly substrates, often in or near reefs or among seagrass. It can be distinguished from the previous species by the numerous small bumps on its carapace and chelipeds. This crab grows to about 8cm wide (carapace only).<br />
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<b>References</b><br />
<ul style="text-align: left;">
<li>Carpenter, K. E. & V. H. Niem (eds), 1998-2001. <i>FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific</i>. Volumes 1 to 6. FAO, Rome. pp. 1-4218.</li>
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>Debelius, H. 1999. <i>Crustacea - Guide of the world</i>. IKAN, Frankfurt. 321pp.</li>
<li>ETI BioInformatics. 2012. <i>Marine species identification portal</i>. Retrieved Jul 8, 2013, from http://species-identification.org.</li>
<li>Ng, P. K. L., S. S. L. Lim, L. K. Wang & L. W. H. Tan. 2007. <i>Private lives: An exposé of Singapore's shores</i>. The Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 212 pp.</li>
<li>Ng, P. K .L., R. T. Corlett & H.T.W. Tan (eds.). 2011. <i>Singapore biodiversity: An encyclopedia of the natural environment and sustainable development</i>. Singapore: Editions Didier Millet. 552 pp.</li>
<li>Štev cic , Z., 1983. Revision of the Calappidae. <i>Memoirs of the Australian Museum</i>, 18: 165–172.</li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
</div>
Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com0tag:blogger.com,1999:blog-9797239.post-58504846933084302252013-07-26T17:34:00.001+08:002013-07-26T18:04:28.221+08:00Rubble Crabs (Phylum Arthropoda: Family Xanthidae) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
Rubble crabs (phylum Arthropoda, subphylum Crustacea, class Malacostraca, order Decapoda, superfamily Xanthoidea, family Xanthidae) are mostly found living among coral rubble, in coral reefs, and rocky shores.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglx3C6a21rS4Q6zF2PeAyBmJLDuSJ28YlNGNGQlRAIi0K3cxG8MWFDlxPtD_sedjgQUhJT-rHrRtVGKP4YK41hbT5SDjOu3TW5k9OGmEllipvrrXQG8XFD2DtIkvQUZxnRhTXo5Q/s1600/Xanthidae.jpg"><img alt="Rubble Crabs (Family Xanthidae)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglx3C6a21rS4Q6zF2PeAyBmJLDuSJ28YlNGNGQlRAIi0K3cxG8MWFDlxPtD_sedjgQUhJT-rHrRtVGKP4YK41hbT5SDjOu3TW5k9OGmEllipvrrXQG8XFD2DtIkvQUZxnRhTXo5Q/s400/Xanthidae.jpg" title="Rubble Crabs (Family Xanthidae)" width="400" /></a><br />
They come in a variety of shapes, and the carapace can be hexagonal to round. Some species may have numerous sharp spines, while others may have blunt lobes or are unarmed. The fingers of the pincers of some species may be spoon-tipped to aid with the scraping of algae from rocks. For most species, the frontal margin between the eyes usually has a notch in the middle.<br />
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Like other true crabs, rubble crabs have a broad carapace, and a very short and flattened abdomen which is usually folded underneath the body. They also have five pairs of "legs" (including the clawed arms, or chelipeds), and hence they are placed in the order Decapoda ("deca" means "ten", while "poda" means "feet"). The gills are leaf-like - a distinctive characteristic of decapods from the suborder Pleocyemata. And as with other crustaceans from the class Malacostraca, their body comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head is fused to the thorax, forming a cephalothorax. They have a tough exoskeleton strengthened with calcium carbonate, and the carapace covers the gills but not the abdomen.<br />
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Rubble crabs reproduce sexually, and have separate sexes. They mate face-to-face, usually with the male on top and the female below. The females can usually be distinguished from the males by having a broader abdomen. This is an adaptation to allow them to carry the eggs under their abdomen until they hatch. <br />
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Rubble crabs are sometimes confused with <a href="http://tidechaser.blogspot.sg/2013/07/swimming-crabs-portunidae-singapore.html">swimming crabs (family Portunidae)</a> due to the hexogonal carapaces of some species, though they lack the paddle-like back legs found in swimming crabs. Some of the species with bigger claws may also be confused with crabs of the superfamily Eriphioidea [such as <a href="http://tidechaser.blogspot.sg/2013/07/forceps-crabs-oziidae-singapore.html">forceps crabs (family Oziidae)</a>, <a href="http://tidechaser.blogspot.sg/2013/07/stone-crabs-menippidae-singapore.html">stone crabs (family Menippidae)</a> and <a href="http://tidechaser.blogspot.sg/2013/07/red-eyed-crabs-eriphiidae-singapore.html">red-eyed crabs (family Eriphiidae)</a>], but the latter usually have huge teeth at the base of the fingers of the pincers. Some rubble crabs may also be confused with <a href="http://tidechaser.blogspot.sg/2013/07/hairy-crabs-pilumnidae-singapore.html">hairy crabs (family Pilumnidae)</a> due to their hairy appearance, but the hairy crabs usually lack the distinctive notch on the frontal margin of the carapace.<br />
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Many species feed on algae, and as a result a number of them are known to be poisonous, due to the toxins in the algae or animals they feed on. Some of the most poisonous crabs in the region are of this family.<br />
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Here are some of the rubble crabs that can be seen Singapore.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0RMxYPvKtcZlXmZx_j8F6dKMOWaEQmHMBFs-5CPZR4qaf6lylxe9umuh8enTg1OVMBP24BDxDGbOPj4VWVsTYlhzTCQ1r4IP0bkwfG3bFSbn99LC6Q56fcM69RMQpPm70IOaftw/s1600/Lophozozymus-pictor.jpg"><img alt="Mosaic Crab (Lophozozymus pictor)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0RMxYPvKtcZlXmZx_j8F6dKMOWaEQmHMBFs-5CPZR4qaf6lylxe9umuh8enTg1OVMBP24BDxDGbOPj4VWVsTYlhzTCQ1r4IP0bkwfG3bFSbn99LC6Q56fcM69RMQpPm70IOaftw/s400/Lophozozymus-pictor.jpg" title="Mosaic Crab (Lophozozymus pictor)" width="400" /></a><br />
The <b>Mosaic Crab (<i>Lophozozymus pictor</i>)</b> is the most poisonous crab in Singapore, with several recorded cases of people being killed by its poison after consuming it. It can be recognised by its smooth red carapace marked with whitish mosaic-like patterns. Juvenile crabs have less of the whitish patterns and more red patches. Studies showed that several toxins are found in this species, though the main toxin is palytoxin, a highly toxic chemical from <a href="http://tidechaser.blogspot.sg/2013/01/zoanthids-zoantharia-of-singapore.html">zoanthids</a>. This crab has been observed to feed on both algae and small animals. It is possible that it can accumulate the toxins from the food it has eaten. A research has also shown that some specimens are not poisonous, adding weight to the theory that it gets the toxins from external sources. The toxin cannot be broken down by heat, making it equally dangerous either cooked or uncooked. The maximum carapace width is about 8cm. It is usually found in or near coral reefs.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBCZDmuh7AChelLQPGkp1i7Z6CmNDfLSb5SsfqOag1RaKDKCVFG9Ec5BhXUwuxw9o1Zfj2758IM4jky1dc4q6-allYIGAOQkqpyRIRaugtepztSDlF8kL8bgLGNKnkmAMj3r-Yww/s1600/Atergatis-integerrimus.jpg"><img alt="Red Egg Crab (Atergatis integerrimus)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBCZDmuh7AChelLQPGkp1i7Z6CmNDfLSb5SsfqOag1RaKDKCVFG9Ec5BhXUwuxw9o1Zfj2758IM4jky1dc4q6-allYIGAOQkqpyRIRaugtepztSDlF8kL8bgLGNKnkmAMj3r-Yww/s400/Atergatis-integerrimus.jpg" title="Red Egg Crab (Atergatis integerrimus)" width="400" /></a><br />
The <b>Red Egg Crab (<i>Atergatis integerrimus</i>)</b> can be recognised by its red oval carapace. The common name comes from the colour and shape of the carapace. Unlike the previous species, it lacks teeth on the carapace's sides. It has been observed to feed on algae and also small animals. This crab is poisonous, though no death cases have been recorded as yet. The maximum carapace width is about 10cm. It is usually found on reef flats among coral rubble and in coral reefs.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMISkBaQeIXmqw9hd7qr70QHnPDDFWFrHRldyRRp0xA23vqlStR8THlHXw0XT_2iZVnNRF_VbnarbacD4R43ayJAgsPAzZUid_R6qKcjbjQY8V45M5IsMmMGSJRzsQITZmXcZGxQ/s1600/Atergatis-floridus.jpg"><img alt="Brown Egg Crab (Atergatis floridus)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMISkBaQeIXmqw9hd7qr70QHnPDDFWFrHRldyRRp0xA23vqlStR8THlHXw0XT_2iZVnNRF_VbnarbacD4R43ayJAgsPAzZUid_R6qKcjbjQY8V45M5IsMmMGSJRzsQITZmXcZGxQ/s400/Atergatis-floridus.jpg" title="Brown Egg Crab (Atergatis floridus)" width="400" /></a><br />
The <b>Brown Egg Crab (<i>Atergatis floridus</i>)</b> has a smooth, brown, oval carapace that is marked with pale flower-like patterns. It has been observed to feed on small animals. It is usually found on reef flats among coral rubble and in coral reefs. The maximum carapace width is about 5cm. This is a very poisonous crab, and several death cases from consuming this species have been recorded.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQccL1qxVddkcG2HWNNafvk2eacefgy-zC13DrYgQwMXD5akpKDE7fqE_CE26m-xgiOVBOotNQcSC009Ad7FuJf6XG0SFk308ruOwJwvqasdluM6lZzhKiMTZgfpfdaS63PT08qQ/s1600/Platypodia-granulosa.jpg"><img alt="Granulated Flatfoot (Platypodia granulosa)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQccL1qxVddkcG2HWNNafvk2eacefgy-zC13DrYgQwMXD5akpKDE7fqE_CE26m-xgiOVBOotNQcSC009Ad7FuJf6XG0SFk308ruOwJwvqasdluM6lZzhKiMTZgfpfdaS63PT08qQ/s400/Platypodia-granulosa.jpg" title="Granulated Flatfoot (Platypodia granulosa)" width="400" /></a><br />
The <b>Granulated Flatfoot (<i>Platypodia granulosa</i>)</b> is the second most poisonous crab in Singapore. It got its common name from the flattened ridges on its legs. It has an oval carapace, and the entire brownish exoskeleton is covered in tiny granules. The maximum carapace width is about 6cm. It is usually found on reef flats or in coral reefs.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg27Rob-UTVfCnrW3-0XRhZe6OtSGQ_fYtl1FuSFXv_Pz6_39IXZk8BCK3FbDwPpjfIpTkPHuOqCJyYr_eeXt_LE86LD-RLZCyGxlfQh0cmNCcf6HzEkOkMPTlXrjfkVSC3ljgPgA/s1600/Cymo-andreossyi.jpg"><img alt="Hairy Coral Crab (Cymo andreossyi)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg27Rob-UTVfCnrW3-0XRhZe6OtSGQ_fYtl1FuSFXv_Pz6_39IXZk8BCK3FbDwPpjfIpTkPHuOqCJyYr_eeXt_LE86LD-RLZCyGxlfQh0cmNCcf6HzEkOkMPTlXrjfkVSC3ljgPgA/s400/Cymo-andreossyi.jpg" title="Hairy Coral Crab (Cymo andreossyi)" width="400" /></a><br />
The <b>Hairy Coral Crab (<i>Cymo andreossyi</i>)</b> is usually found living among branching corals (such as <i>Acropora</i> spp. or <i>Pocillopora </i>spp.). This tiny crab is about 1cm wide, and can be easily distinguished from other small crabs living in corals by their hairy appearance. They mostly feed on the mucus produced by the corals, but are known to also feed on detritus (tiny decaying matter).<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgL2oXOwKpFm4KfZUYy-kvsX1epkwMbYgQ2tXu5nWTv1lfOfpS2ZLJ32_F1MhhEFX8GX7lv19H5xqgILLY3iKl3aWGIiufJOG_0STuPdDxe5lEd-zihT0ZpdmdD5MLqjDqC1Wyqaw/s1600/Euxanthus-exsculptus.jpg"><img alt="Exsculptate Rubble Crab (Euxanthus exsculptus)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgL2oXOwKpFm4KfZUYy-kvsX1epkwMbYgQ2tXu5nWTv1lfOfpS2ZLJ32_F1MhhEFX8GX7lv19H5xqgILLY3iKl3aWGIiufJOG_0STuPdDxe5lEd-zihT0ZpdmdD5MLqjDqC1Wyqaw/s400/Euxanthus-exsculptus.jpg" title="Exsculptate Rubble Crab (Euxanthus exsculptus)" width="400" /></a><br />
The <b>Exsculptate Rubble Crab (<i>Euxanthus exsculptus</i>)</b> has numerous variable and irregular depressed lines on its carapace that resemble sculptured work. It is sometimes seen in coral reefs or among coral rubble. The carapace gets to a maximum width of about 6cm.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgKdMNuMg8h1UO-Vs_dhtWe8DtaKDZjRhLAYSHQmKm0BYJpP6xx6ZRhQ3A512SaczIdNGTN3prhJ6qiLIE50ZSVZFcmy6ahGnl2Zt3UGSYdcxBu4xttpxC8byBVJeZsMeptfP79ig/s1600/Etisus_laevimanus.jpg"><img alt="Smooth Spooner (Etisus laevimanus)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgKdMNuMg8h1UO-Vs_dhtWe8DtaKDZjRhLAYSHQmKm0BYJpP6xx6ZRhQ3A512SaczIdNGTN3prhJ6qiLIE50ZSVZFcmy6ahGnl2Zt3UGSYdcxBu4xttpxC8byBVJeZsMeptfP79ig/s400/Etisus_laevimanus.jpg" title="Smooth Spooner (Etisus laevimanus)" width="400" /></a><br />
The <b>Smooth Spooner (<i>Etisus laevimanus</i>)</b> got its name from the smooth carapace and the spoon-like tips of the pincer fingers. The spoon-like tips allow the crab to scrape algae and detritus off the rocks to feed on. The colour and patterns of this species are very variable, from grey to reddish brown, and often with patches of a different colour on the back.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhGYrJoiF3jslHRftFL-bkn3MvbWwAbVXzBuXv_HxbxIELCF64F1jxfLUK4xRRshu_TcDh6dzjFPeXiYeZQRAstoC5vhPYhFbPvax4q58yoJArSe60aPN2JFBSsMW0kmi8jfMtgiw/s1600/Etisus-laevimanus.jpg"><img alt="Smooth Spooner (Etisus laevimanus)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhGYrJoiF3jslHRftFL-bkn3MvbWwAbVXzBuXv_HxbxIELCF64F1jxfLUK4xRRshu_TcDh6dzjFPeXiYeZQRAstoC5vhPYhFbPvax4q58yoJArSe60aPN2JFBSsMW0kmi8jfMtgiw/s400/Etisus-laevimanus.jpg" title="Smooth Spooner (Etisus laevimanus)" width="400" /></a><br />
The above photo features a smooth spooner that is all brownish without patches of other colours. This crab grows to about 8cm wide (carapace only), and it sometimes consumed. However, studies suggest that some specimens may be mildly poisonous. It is usually found on coral reefs, areas with coral rubble, and sometimes rocky areas.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjSnwy9ee6Q6uAtkz08uTWxrjl8ccX2lnQ3yOgntWC0-N5g2SjBjoiUVKWQ6vK66WiwGATbLAYIjdKV_CPWjD8fxP0QWRhT21lEtPlZXJJc2oxu-wcc2du_GqJuhZh6MchANKt1ZA/s1600/Etisus_utilis.jpg"><img alt="Sawedged Spooner (Etisus utilis)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjSnwy9ee6Q6uAtkz08uTWxrjl8ccX2lnQ3yOgntWC0-N5g2SjBjoiUVKWQ6vK66WiwGATbLAYIjdKV_CPWjD8fxP0QWRhT21lEtPlZXJJc2oxu-wcc2du_GqJuhZh6MchANKt1ZA/s400/Etisus_utilis.jpg" title="Sawedged Spooner (Etisus utilis)" width="400" /></a><br />
The <b>Sawedged Spooner (<i>Etisus utilis</i>)</b> can be easily distinguished from the previous species by the sharp spines on the sides of the carapace, which gives it its common name. This large crab has a maximum carapace width of about 15cm, and is sometimes caught for consumption. It is mostly brown, though some specimens may have pale patterns on the carapace. Studies suggest that this species may be mildly poisonous in some places though. It is usually found on coral reefs. This species has spoon-tipped pincer fingers as well, which allow it to scrape off algae and detritus from rocks.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhA2RZCPDT-I6G4JEjQg00BGI4fEm1i1o68aJwtjxxEBg8Bb-fXLOrqZgSg7iZ135_RvO5JWQ4lmZK0r13GFjogtjChJ2oWipKTyFv7hy9Ga3OSu-sdSbxHFhuDzI3UynDtpEVbqA/s1600/leptodius1.jpg"><img alt="Rock Crab (Leptodius sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhA2RZCPDT-I6G4JEjQg00BGI4fEm1i1o68aJwtjxxEBg8Bb-fXLOrqZgSg7iZ135_RvO5JWQ4lmZK0r13GFjogtjChJ2oWipKTyFv7hy9Ga3OSu-sdSbxHFhuDzI3UynDtpEVbqA/s400/leptodius1.jpg" title="Rock Crab (Leptodius sp.)" width="400" /></a><br />
<b>Rock Crabs (<i>Leptodius</i> spp.)</b> are very commonly found on rocky shores and coral reefs. They are usually found hiding under rocks and coral rubble, and the carapace width seldom exceed 3.5cm. The fingers of their pincers are spoon-tipped as well, allowing them to scrape algae and detritus off rocks to feed on.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBMDOEZAJq7m3erRumAHW_CY3mdZ5igIF2wjtBa5WP0DWdBjXOc5BJwWFdgcmkHz0NFj2WeWGjjlkQfDxZ_ZZ9Xtn5n9PsbwfnCca63PdOUTAr7TLSUzneHBrYQUVSmCDSrjfQ8A/s1600/Leptodius.jpg"><img alt="Rock Crab (Leptodius sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBMDOEZAJq7m3erRumAHW_CY3mdZ5igIF2wjtBa5WP0DWdBjXOc5BJwWFdgcmkHz0NFj2WeWGjjlkQfDxZ_ZZ9Xtn5n9PsbwfnCca63PdOUTAr7TLSUzneHBrYQUVSmCDSrjfQ8A/s400/Leptodius.jpg" title="Rock Crab (Leptodius sp.)" width="400" /></a><br />
The above photo features another <b>Rock Crab (<i>Leptodius </i>sp.)</b> of a different colour<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjLW9fqhTkrrUD3NLpHDCvYkexR2QbqLQI83YaXtOpBsjr0hvAIugzsNTrxj8WoNP2jg5bMgTz6OOZLAITtf9Y0SNnbtyRYHq9pt_WkLPXxF0Ov8R5Rw-kRB2u6LQ2IhzRkU9UehQ/s1600/xanthid.jpg"><img alt="Rock Crab (Leptodius sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjLW9fqhTkrrUD3NLpHDCvYkexR2QbqLQI83YaXtOpBsjr0hvAIugzsNTrxj8WoNP2jg5bMgTz6OOZLAITtf9Y0SNnbtyRYHq9pt_WkLPXxF0Ov8R5Rw-kRB2u6LQ2IhzRkU9UehQ/s400/xanthid.jpg" title="Rock Crab (Leptodius sp.)" width="400" /></a><br />
Some Rock Crabs are very tiny, hardly more than 1cm wide.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgnmx38N8JEiT8Rj_9iUtN89XgysastE1bOswtXlTYtyl06a-nuOpS-QHJH9n26Ft8S22fTxApdtaWgMh2acz_iKwQu0fcuFCjjf0PNyJnfLVoKhGnsNaps30k9vOVEc4WvioPZUA/s1600/xanthidae.jpg"><img alt="Rock Crab (Leptodius sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgnmx38N8JEiT8Rj_9iUtN89XgysastE1bOswtXlTYtyl06a-nuOpS-QHJH9n26Ft8S22fTxApdtaWgMh2acz_iKwQu0fcuFCjjf0PNyJnfLVoKhGnsNaps30k9vOVEc4WvioPZUA/s400/xanthidae.jpg" title="Rock Crab (Leptodius sp.)" width="400" /></a><br />
This tiny female Rock Crab is gravid (with eggs), showing that it is already mature despite the small size. Like other Rock Crabs, the tips of the fingers of its pincers are spoon-like.<br />
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<b>References</b><br />
<ul style="text-align: left;">
<li>Carpenter, K. E. & V. H. Niem (eds), 1998-2001. <i>FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific</i>. Volumes 1 to 6. FAO, Rome. pp. 1-4218.</li>
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>Debelius, H. 1999. <i>Crustacea - Guide of the world</i>. IKAN, Frankfurt. 321pp.</li>
<li>ETI BioInformatics. 2012. <i>Marine species identification portal</i>. Retrieved Jul 8, 2013, from http://species-identification.org.</li>
<li>Lau, C. O., C. H. Tan, H. E. Khoo, R. Yuen, R. J. Lewis, G. P. Corpuz & G. S. Bignami. 1995. Lophozozymus pictor toxin: A fluorescent structural isomer of palytoxin. <i>Toxicon </i>33(10): 1373-1377 </li>
<li>Ng, P. K. L., S. S. L. Lim, L. K. Wang & L. W. H. Tan. 2007. <i>Private lives: An exposé of Singapore's shores</i>. The Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 212 pp.</li>
<li>Ng, P. K .L., R. T. Corlett & H.T.W. Tan (eds.). 2011. <i>Singapore biodiversity: An encyclopedia of the natural environment and sustainable development</i>. Singapore: Editions Didier Millet. 552 pp.</li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
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Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com0tag:blogger.com,1999:blog-9797239.post-1918776783647856752013-07-26T17:26:00.000+08:002013-07-26T18:04:28.203+08:00Hairy Crabs (Phylum Arthropoda: Family Pilumnidae) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
Hairy crabs (phylum Arthropoda, subphylum Crustacea, class Malacostraca, order Decapoda, superfamily Pilumnoidea, family Pilumnidae), despite the common name, do not always spot a hairy appearance. Most of the commonly seen species in Singapore have hairy or granulated exoskeletons though.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjuuBSIqp_VJHeZIWzA5pC_aYCG7WBFthFvOsEHDIQE58v9ty8bzIl8Fw4s3cmT3BpE5Cy63yCLIcP-TUpGBDCtyffZwS1kWbv7-tbZu4YsYCOh4o14IZOi48fcDJC1z3wR8qRIOA/s1600/Pilumnidae.jpg"><img alt="Hairy Crabs (Family Pilumnidae)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjuuBSIqp_VJHeZIWzA5pC_aYCG7WBFthFvOsEHDIQE58v9ty8bzIl8Fw4s3cmT3BpE5Cy63yCLIcP-TUpGBDCtyffZwS1kWbv7-tbZu4YsYCOh4o14IZOi48fcDJC1z3wR8qRIOA/s400/Pilumnidae.jpg" title="Hairy Crabs (Family Pilumnidae)" width="400" /></a>
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The hair and granules help to break the shape of the animal and trap sediment, and hence allow it to camouflage with the surrounding. Some hairy crabs are found to be poisonous, possibly because they feed on marine algae and sessile cnidarians (such as zoanthids), some of which may contain toxins. Hairy crabs have been observed to actively hunt other small animals to feed on as well.<br />
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Like other true crabs, hairy crabs have a broad carapace, and a very short and flattened abdomen which is usually folded underneath the body. They also have five pairs of "legs" (including the clawed arms, or chelipeds), and hence they are placed in the order Decapoda ("deca" means "ten", while "poda" means "feet"). The gills are leaf-like - a distinctive characteristic of decapods from the suborder Pleocyemata. And as with other crustaceans from the class Malacostraca, their body comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head is fused to the thorax, forming a cephalothorax. They have a tough exoskeleton strengthened with calcium carbonate, and the carapace covers the gills but not the abdomen.<br />
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Hairy crabs reproduce sexually, and have separate sexes. They mate face-to-face, usually with the male on top and the female below. The females can usually be distinguished from the males by having a broader abdomen. This is an adaptation to allow them to carry the eggs under their abdomen until they hatch.<br />
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Some species can be confused with <a href="http://tidechaser.blogspot.sg/2013/07/red-eyed-crabs-eriphiidae-singapore.html">red-eyed crabs (family Eriphiidae)</a>, but they can be distinguished by the lack of a large tooth at the base of the upper finger of the pincer. The carapace is usually hexagonal or somewhat ovate. They are also sometimes confused with some of the hairier <a href="http://tidechaser.blogspot.sg/2013/07/rubble-crabs-xanthidae-singapore.html">rubble crabs (family Xanthidae</a>), but they usually lack the distinctive notch found on the frontal margin of the carapace of the latter.<br />
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Here are the hairy crabs that I have photographed in Singapore.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiDhEO7LF1IR2QsiTY6fDkJA0LEa67evxCuaXkXVL7LhoTah05LEgqKcuOzjHLD0mh7UL9PzgJ3jd-dFfFKURMfU7oEKVL9kiSI2jxKGRL6wqpvZ_F3PCmxCCS1jm_MbAGqRYXClA/s1600/Pilumnus-vespertilio.jpg"><img alt="Common Hairy Crab (Pilumnus vespertilio)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiDhEO7LF1IR2QsiTY6fDkJA0LEa67evxCuaXkXVL7LhoTah05LEgqKcuOzjHLD0mh7UL9PzgJ3jd-dFfFKURMfU7oEKVL9kiSI2jxKGRL6wqpvZ_F3PCmxCCS1jm_MbAGqRYXClA/s400/Pilumnus-vespertilio.jpg" title="Common Hairy Crab (Pilumnus vespertilio)" width="400" /></a><br />
The <b>Common Hairy Crab (<i>Pilumnus vespertilio</i>)</b> is very commonly seen in the intertidal areas of Singapore in a variety of habitats, ranging from seagrass meadows to coral rubble flats. The long hair covering its exoskeleton traps sediment, allowing it to blend nicely into the surrounding sand. Some people call it the teddy bear crab due to its hairy appearance. Its carapace gets to a maximum width of about 3cm.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgn4PRqEs3uF-Pi5FMt2ca1sxWA3oTlSrVHmRsvP1xTRV3exAifxRlII2qSWOlA2y-MffInot-HRupkvXTeVFUlSPHF5cZcQNVgCYjEss6xNmFAVrVAZtJQIjj1ASDMYjDs566VmQ/s1600/Pilumnus-vespertilio.jpg"><img alt="Common Hairy Crab (Pilumnus vespertilio) eating cardinalfish" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgn4PRqEs3uF-Pi5FMt2ca1sxWA3oTlSrVHmRsvP1xTRV3exAifxRlII2qSWOlA2y-MffInot-HRupkvXTeVFUlSPHF5cZcQNVgCYjEss6xNmFAVrVAZtJQIjj1ASDMYjDs566VmQ/s400/Pilumnus-vespertilio.jpg" title="Common Hairy Crab (Pilumnus vespertilio) eating cardinalfish" width="400" /></a><br />
The Common Hairy Crab has been observed eating algae and small fishes. The above photo features one which had caught a small cardinalfish and broke the latter's body into two.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi7U07cHQGPGg2t_9RqiLO-yyITzt33_jtSNgmT24xSMOipf5mvZIudIoQDYhaCr69oiUelj7CAH5m4Ahs3k8PPGjYwts-aP4d1l9QRDcg5NUQy_rBFoOAJqa3p379hBJ0xmUCRDA/s1600/Actumnus-setifer.jpg"><img alt="Short-haired Crab (Actumnus setifer)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi7U07cHQGPGg2t_9RqiLO-yyITzt33_jtSNgmT24xSMOipf5mvZIudIoQDYhaCr69oiUelj7CAH5m4Ahs3k8PPGjYwts-aP4d1l9QRDcg5NUQy_rBFoOAJqa3p379hBJ0xmUCRDA/s400/Actumnus-setifer.jpg" title="Short-haired Crab (Actumnus setifer)" width="400" /></a><br />
The <b>Short-haired Crab (<i>Actumnus setifer</i>)</b> lives in burrows it has excavated in living or dead coral fragments. Like a hermit crab, it carries this mobile home from place to place. The crab is covered with short fine hairs (as the common name suggests) and numerous granules. It is reddish in colour, and grows to about 2cm wide.<br />
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<b>References</b><br />
<ul style="text-align: left;">
<li>Carpenter, K. E. & V. H. Niem (eds), 1998-2001. <i>FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific</i>. Volumes 1 to 6. FAO, Rome. pp. 1-4218.</li>
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>Debelius, H. 1999. <i>Crustacea - Guide of the world</i>. IKAN, Frankfurt. 321pp.</li>
<li>Johnson, P. R., P. J. F. Davie, D. T. Neil & I. Fellegara. 2008. Excavation, habitation and transportation of massive corals by the crab <i>Actumnus setifer</i> (Crustacea: Brachyura: Pilumnidae) in Moreton Bay, Queensland. <i>Memoirs of the Queensland Museum - Nature</i>, 54 1: 261-271. </li>
<li>Ng, P. K. L., S. S. L. Lim, L. K. Wang & L. W. H. Tan. 2007. <i>Private lives: An exposé of Singapore's shores</i>. The Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 212 pp.</li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
</div>
Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com0tag:blogger.com,1999:blog-9797239.post-66527736548578993902013-07-26T17:19:00.000+08:002013-07-26T18:04:28.226+08:00Stone Crabs (Phylum Arthropoda: Family Menippidae) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
Stone crabs (phylum Arthropoda, subphylum Crustacea, class Malacostraca, order Decapoda, superfamily Eriphioidea, family Menippidae) are commonly found in rocky areas or reef flats.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQOeWutX8-TGgGWIlaXRBPGIS5jfMBzjGL89Yj54JmLAVKEaUYveSozNYijHKs7L8whYEUDi4sKPHnDfez9hxWWvOfDEfjDXukiX8UigBTKHyQ_mcIxfCmJqvnOII5oSqEXbiuPw/s1600/Menippidae.jpg"><img alt="Stone Crabs (Family Menippidae)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQOeWutX8-TGgGWIlaXRBPGIS5jfMBzjGL89Yj54JmLAVKEaUYveSozNYijHKs7L8whYEUDi4sKPHnDfez9hxWWvOfDEfjDXukiX8UigBTKHyQ_mcIxfCmJqvnOII5oSqEXbiuPw/s400/Menippidae.jpg" title="Stone Crabs (Family Menippidae)" width="400" /></a><br />
Their carapace is usually somewhat hexagonal to ovate, and the side margins nearer to the front is usually marked with crested teeth (i.e. the top surface of the teeth is not flat, but ridge-like, somewhat like the corner of a roof, as shown in the left-bottom picture). They typically have large and powerful asymmetrical chelipeds (i.e. the clawed arms), and a large molar-like tooth can be found near the base of the top finger, allowing them to crush and break shells of molluscan prey.<br />
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Like other true crabs, stone crabs have a broad carapace, and a very short and flattened abdomen which is usually folded underneath the body. They also have five pairs of "legs" (including the clawed arms, or chelipeds), and hence they are placed in the order Decapoda ("deca" means "ten", while "poda" means "feet"). The gills are leaf-like - a distinctive characteristic of decapods from the suborder Pleocyemata. And as with other crustaceans from the class Malacostraca, their body comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head is fused to the thorax, forming a cephalothorax. They have a tough exoskeleton strengthened with calcium carbonate, and the carapace covers the gills but not the abdomen.<br />
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Stone crabs reproduce sexually, and have separate sexes. They mate face-to-face, usually with the male on top and the female below. The females can usually be distinguished from the males by having a broader abdomen. This is an adaptation to allow them to carry the eggs under their abdomen until they hatch. <br />
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Stone crabs are sometimes confused with <a href="http://tidechaser.blogspot.sg/2013/07/rubble-crabs-xanthidae-singapore.html">rubble crabs (family Xanthidae</a>), <a href="http://tidechaser.blogspot.sg/2013/07/swimming-crabs-portunidae-singapore.html">mud crabs (<i>Scylla </i>spp.)</a>, and other crabs of the same superfamily Eriphioidea [such as <a href="http://tidechaser.blogspot.sg/2013/07/forceps-crabs-oziidae-singapore.html">forceps crabs (family Oziidae)</a> and <a href="http://tidechaser.blogspot.sg/2013/07/red-eyed-crabs-eriphiidae-singapore.html">red-eyed crabs (family Eriphiidae)</a>]. Unlike rubble crabs, stone crabs have a large molar-like tooth near the base of the top finger of each pincer. They can be easily distinguished from the mud crabs by the lack of paddle-like back legs found in the latter. They can also be distinguished from other crabs of the superfamily Eriphioidea by having crested teeth by the sides of the carapace.<br />
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Here are some of the stone crabs that can be seen Singapore.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtrmI2EPo5iFnMczTkmBgS5VKwam9ax6h8-P96qECxZl0gew-m_GCOi1NMihMZEoahcE8mNWQeY3EqtvZl9W9fcOGp82MMDF7s9rHtdQ-rqpabiFUnoOh72s6Vn4aGvp2yWrKbTA/s1600/Myomenippe-hardwickii.jpg"><img alt="Thunder Crab (Myomenippe hardwickii)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtrmI2EPo5iFnMczTkmBgS5VKwam9ax6h8-P96qECxZl0gew-m_GCOi1NMihMZEoahcE8mNWQeY3EqtvZl9W9fcOGp82MMDF7s9rHtdQ-rqpabiFUnoOh72s6Vn4aGvp2yWrKbTA/s400/Myomenippe-hardwickii.jpg" title="Thunder Crab (Myomenippe hardwickii)" width="400" /></a><br />
The <b>Thunder Crab (<i>Myomenippe hardwickii</i>)</b> has an ovate carapace covered with numerous tiny granules. The colour ranges from a dirty brown to sometimes reddish brown. It can be distinguished from other similar-looking crabs by its green eyes. The Thunder Crab is usually found in mangroves or rocky shores, sometimes hiding under rocks or in crevices. Its massive claws with the large molar-like tooth can be found near the base of the top finger allow it to crush shelled prey and other small animals to feed on. The carapace gets to about 10cm wide. The Thunder Crab gets its common name from the belief that once it gets its claws on a human, only a clap of thunder can make it release its grip. This is certainly not true. If a person gets pinched by a Thunder Crab, it is best to put the crab into water, and with luck it may release its grip. If not, he/she may have to pull off the claw and pry it open.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgS5RB7yZO8xO_TOHmMhEoqaNa0y-dZyFuOoxp0ptq0qoayuMyZvDtK9xWK0b65CmU5hu6fEWLYEVT5lMiB-F_nuT7Ov0MK3nspLO1JdZywT1MwshL14abaZE_s0EddPgWjyhchGw/s1600/unknown08.jpg"><img alt="Thunder Crab (Myomenippe hardwickii)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgS5RB7yZO8xO_TOHmMhEoqaNa0y-dZyFuOoxp0ptq0qoayuMyZvDtK9xWK0b65CmU5hu6fEWLYEVT5lMiB-F_nuT7Ov0MK3nspLO1JdZywT1MwshL14abaZE_s0EddPgWjyhchGw/s400/unknown08.jpg" title="Thunder Crab (Myomenippe hardwickii)" width="400" /></a><br />
The colour of Thunder Crabs may vary, depending on the habitat, and the above photo features one with a more reddish brown coloration. The green eyes distinguish it from other similar species though. This species is often collected for food. Sometimes, fishermen may just detach the massive claws, and throw the animals back into the water. It is often more common to only see the claws being sold in the market rather than the entire animal.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhL8P6MME_YA4iZXmospzy1HFhQlni1d07UJzuqXmA8F6eqDXub4BFkkZ-88-h_qfEazk1MJ9Yb8ZwOfGQSQ3TPPObY7KbUXHnOYpPlqBGK1YaAgiCvL-kfxNugR9O4XfwT65sv9g/s1600/Menippe-rumphii.jpg"><img alt="Maroon Stone Crab (Menippe rumphii)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhL8P6MME_YA4iZXmospzy1HFhQlni1d07UJzuqXmA8F6eqDXub4BFkkZ-88-h_qfEazk1MJ9Yb8ZwOfGQSQ3TPPObY7KbUXHnOYpPlqBGK1YaAgiCvL-kfxNugR9O4XfwT65sv9g/s400/Menippe-rumphii.jpg" title="Maroon Stone Crab (Menippe rumphii)" width="400" /></a><br />
The <b>Maroon Stone Crab (<i>Menippe rumphii</i>)</b>, sometimes also called the Red Stone Crab, can be distinguished from the previous species by its red eyes. It is usually pinkish red or maroon in colour. This crab grows to about 9cm wide (carapace only), and like the previous species, usually only the claws are retained for sale in the market. It feeds on small animals, including shelled invertebrates, which it crushes with its massive claws.<br />
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<hr />
<br />
<b>References</b><br />
<ul style="text-align: left;">
<li>Carpenter, K. E. & V. H. Niem (eds), 1998-2001. <i>FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific</i>. Volumes 1 to 6. FAO, Rome. pp. 1-4218.</li>
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>Debelius, H. 1999. <i>Crustacea - Guide of the world</i>. IKAN, Frankfurt. 321pp.</li>
<li>Ng, P. K. L., L. K. Wang & K. K. P. Lim (eds.). 2008. Private Lives: An Exposé of Singapore’s Mangroves. The Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 240 pp. </li>
<li>Ng, P. K. L., S. S. L. Lim, L. K. Wang & L. W. H. Tan. 2007. <i>Private lives: An exposé of Singapore's shores</i>. The Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 212 pp.</li>
<li>Ng, P. K .L., R. T. Corlett & H.T.W. Tan (eds.). 2011. <i>Singapore biodiversity: An encyclopedia of the natural environment and sustainable development</i>. Singapore: Editions Didier Millet. 552 pp.</li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
</div>
Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com0tag:blogger.com,1999:blog-9797239.post-23019370759782165942013-07-26T17:15:00.001+08:002013-07-26T18:04:28.205+08:00Red-eyed Crabs (Phylum Arthropoda: Family Eriphiidae) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
Red-eyed crabs (phylum Arthropoda, subphylum Crustacea, class Malacostraca, order Decapoda, superfamily Eriphioidea, family Eriphiidae) typically have red eyes, though this is not a useful distinguishing feature since may other crabs share this characteristic.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWtA-DteEGZvwQZYFhnRCQ2PoH3wW3vjwDgnw3M1ov4408_2I1Tt49tkGLdlOuUKTu-ypHlSYWebrCykq3zj14kVapgqGzdGklp-gdfTPTRl_4RUfvyVFaqiN9SfUC2ygstBs_qQ/s1600/Eriphia_ferox.jpg"><img alt="Red-eyed Reef Crab (Eriphia ferox)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWtA-DteEGZvwQZYFhnRCQ2PoH3wW3vjwDgnw3M1ov4408_2I1Tt49tkGLdlOuUKTu-ypHlSYWebrCykq3zj14kVapgqGzdGklp-gdfTPTRl_4RUfvyVFaqiN9SfUC2ygstBs_qQ/s400/Eriphia_ferox.jpg" title="Red-eyed Reef Crab (Eriphia ferox)" width="400" /></a><br />
They have hexagonal to ovate carapace, and the chelipeds are usually large and powerful. The carapace and chelipeds are usually covered in fine, spiky bumps, and the front margin of the carapace is usually marked with lobes or spines. They typically have large and powerful asymmetrical chelipeds, and a large molar-like tooth can be found near the base of the top finger, allowing them to crush and break shells of molluscan prey. Studies suggest that some species include algae as part of their diet as well.<br />
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Like other true crabs, red-eyed crabs have a broad carapace, and a very short and flattened abdomen which is usually folded underneath the body. They also have five pairs of "legs" (including the clawed arms, or chelipeds), and hence they are placed in the order Decapoda ("deca" means "ten", while "poda" means "feet"). The gills are leaf-like - a distinctive characteristic of decapods from the suborder Pleocyemata. And as with other crustaceans from the class Malacostraca, their body comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head is fused to the thorax, forming a cephalothorax. They have a tough exoskeleton strengthened with calcium carbonate, and the carapace covers the gills but not the abdomen.<br />
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Red-eyed crabs reproduce sexually, and have separate sexes. They mate face-to-face, usually with the male on top and the female below. The females can usually be distinguished from the males by having a broader abdomen. This is an adaptation to allow them to carry the eggs under their abdomen until they hatch.<br />
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At the moment, I have only photographed one species of red-eyed crabs in Singapore. <br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhAIayTJ0PA0HySxIN0TfVP1ms9Yq_0x3Vfkus3AZHJ05ztIPUzla1hvMUqbSQvuw7Gi_jUY2apliTLriAlQNb0GNcNk1ulvpvc6nIq18FX7glqXw-xVEFTSxUrRc4fqcL2NSVgCQ/s1600/Eriphia-ferox.jpg"><img alt="Red-eyed Reef Crab (Eriphia ferox)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhAIayTJ0PA0HySxIN0TfVP1ms9Yq_0x3Vfkus3AZHJ05ztIPUzla1hvMUqbSQvuw7Gi_jUY2apliTLriAlQNb0GNcNk1ulvpvc6nIq18FX7glqXw-xVEFTSxUrRc4fqcL2NSVgCQ/s400/Eriphia-ferox.jpg" title="Red-eyed Reef Crab (Eriphia ferox)" width="400" /></a><br />
The <b>Red-eyed Reef Crab (<i>Eriphia ferox</i>)</b> is usually found in intertidal or subtidal coral reefs or coral rubble flats. It has a dark reddish brown, somewhat rectangular carapace covered in spiky granules. It is sometimes collected for consumption, but is said to be poisonous in some areas, possibly depending on their diet. The maximum carapace width is about 6cm.<br />
<br />
Red-eyed crabs are sometimes confused with <a href="http://tidechaser.blogspot.sg/2013/07/rubble-crabs-xanthidae-singapore.html">rubble crabs (family Xanthidae</a>) and other crabs of the same superfamily Eriphioidea, such as <a href="http://tidechaser.blogspot.sg/2013/07/forceps-crabs-oziidae-singapore.html">forceps crabs (family Oziidae)</a> and <a href="http://tidechaser.blogspot.sg/2013/07/stone-crabs-menippidae-singapore.html">stone crabs (family Menippidae</a>). Unlike rubble crabs, forceps crabs have the large curved tooth near the base of the top finger of the bigger pincer. They can be distinguished from other crabs of the superfamily Eriphioidea by the spiky granules on their carapaces.<br />
<br />
<hr />
<br />
<b>References</b><br />
<ul style="text-align: left;">
<li>Carpenter, K. E. & V. H. Niem (eds), 1998-2001. <i>FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific</i>. Volumes 1 to 6. FAO, Rome. pp. 1-4218.</li>
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>Ng, P. K. L., S. S. L. Lim, L. K. Wang & L. W. H. Tan. 2007. <i>Private lives: An exposé of Singapore's shores</i>. The Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 212 pp.</li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
</div>
Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com0tag:blogger.com,1999:blog-9797239.post-56042516926697163702013-07-26T17:11:00.000+08:002013-07-26T18:04:28.217+08:00Forceps Crabs (Phylum Arthropoda: Family Oziidae) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
Forceps crabs (phylum Arthropoda, subphylum Crustacea, class Malacostraca, order Decapoda, superfamily Eriphioidea, family Oziidae) typically have asymmetrical chelipeds (i.e. the clawed arms), with the larger one having a gently curved tooth at the base of the top finger, and the smaller cheliped with slender fingers, much like a pair of forceps.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhBYg6bqzp8Bgbk7E7hvBLunVp1gZDmq3mXRCc7NldqHZWeVzTjNeGfLl_WEvMexux_5Kv5ebuZEmZuDsjU10o2nv2EyFT1qlOXH9ju9D1nlvg9V1vgYiGu7x4H30_TLL3Sx9Q_zw/s1600/Oziidae.jpg"><img alt="Forcep Crabs (Family Oziidae)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhBYg6bqzp8Bgbk7E7hvBLunVp1gZDmq3mXRCc7NldqHZWeVzTjNeGfLl_WEvMexux_5Kv5ebuZEmZuDsjU10o2nv2EyFT1qlOXH9ju9D1nlvg9V1vgYiGu7x4H30_TLL3Sx9Q_zw/s400/Oziidae.jpg" title="Forcep Crabs (Family Oziidae)" width="400" /></a><br />
The curved tooth is for cutting a channel into the opening of snails (much like a can-opener as the crab turns the shell to cut a channel), while the forceps-like pincers extract the exposed flesh. Some species may develop a molariform tooth as the crab matures, which allows the crab to crush the shells of both molluscs and crustaceans. The carapace may be hexagonal or ovate, the front half of the margin is lined with numerous teeth. Forceps crabs are usually found hiding among rocks or roots.<br />
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Like other true crabs, forceps crabs have a broad carapace, and a very short and flattened abdomen which is usually folded underneath the body. They also have five pairs of "legs" (including the clawed arms, or chelipeds), and hence they are placed in the order Decapoda ("deca" means "ten", while "poda" means "feet"). The gills are leaf-like - a distinctive characteristic of decapods from the suborder Pleocyemata. And as with other crustaceans from the class Malacostraca, their body comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head is fused to the thorax, forming a cephalothorax. They have a tough exoskeleton strengthened with calcium carbonate, and the carapace covers the gills but not the abdomen.<br />
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Forceps crabs reproduce sexually, and have separate sexes. They mate face-to-face, usually with the male on top and the female below. The females can usually be distinguished from the males by having a broader abdomen. This is an adaptation to allow them to carry the eggs under their abdomen until they hatch. <br />
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Forceps crabs are sometimes confused with <a href="http://tidechaser.blogspot.sg/2013/07/rubble-crabs-xanthidae-singapore.html">rubble crabs (family Xanthidae</a>), <a href="http://tidechaser.blogspot.sg/2013/07/swimming-crabs-portunidae-singapore.html">mud crabs (<i>Scylla </i>spp.)</a>, and other crabs of the same superfamily Eriphioidea [such as <a href="http://tidechaser.blogspot.sg/2013/07/stone-crabs-menippidae-singapore.html">stone crabs (family Menippidae</a>) and <a href="http://tidechaser.blogspot.sg/2013/07/red-eyed-crabs-eriphiidae-singapore.html">red-eyed crabs (family Eriphiidae)</a>]. Unlike rubble crabs, forceps crabs have the large curved tooth near the base of the top finger of the bigger pincer. They can be easily distinguished from the mud crabs by the lack of paddle-like back legs found in the latter. They can also be distinguished from other crabs of the superfamily Eriphioidea by having thin and long fingers (hence forceps-like) on the smaller chelipeds.<br />
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Here are some of the forceps crabs that can be seen Singapore.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8v0_8Rto2rjLuoEt0je0Xh3p7M80qZ18vOEr7t2ZbFrOGf3r2nYQOwPcO5OsgtlB3xZCnd4JoEkJwmLuZ1QUZu-djRxNUjKG1PcRIntjNCLYlbjIiGsdiKtzS44uKNcX1uGAAHw/s1600/Epixanthus-dentatus.jpg"><img alt="Mangrove Forceps Crab (Epixanthus dentatus)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8v0_8Rto2rjLuoEt0je0Xh3p7M80qZ18vOEr7t2ZbFrOGf3r2nYQOwPcO5OsgtlB3xZCnd4JoEkJwmLuZ1QUZu-djRxNUjKG1PcRIntjNCLYlbjIiGsdiKtzS44uKNcX1uGAAHw/s400/Epixanthus-dentatus.jpg" title="Mangrove Forceps Crab (Epixanthus dentatus)" width="400" /></a><br />
The <b>Mangrove Forceps Crab (<i>Epixanthus dentatus</i>)</b> can usually be recognised by the orange spots on its back, except that it is sometimes covered in mud. In such situations, it may be easier to recognise it by its thin and forceps-like smaller claw, and a larger claw with a curved tooth at the base of the upper finger. Studies have shown that it feeds on both crustaceans and shelled molluscs. It uses its large claw with the curved tooth like a can-opener to cut a channel on the shell of its prey or crush the shell altogether, and uses the smaller claw to extract the exposed flesh.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMpdE3iBq9c7mPd2m2OnQwMyn0r0gC2RP7TW0rDEDLXWY93MJQ5wKxoCoN2BgtG0NVjget5n-ci8y_ODwQzidPe5AYJKZ0f3eyfJb001c_6dSPi3TjCcYQ4BEv83sHwCJC5UfkcA/s1600/Epixanthus_dentatus.jpg"><img alt="Mangrove Forceps Crab (Epixanthus dentatus)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMpdE3iBq9c7mPd2m2OnQwMyn0r0gC2RP7TW0rDEDLXWY93MJQ5wKxoCoN2BgtG0NVjget5n-ci8y_ODwQzidPe5AYJKZ0f3eyfJb001c_6dSPi3TjCcYQ4BEv83sHwCJC5UfkcA/s400/Epixanthus_dentatus.jpg" title="Mangrove Forceps Crab (Epixanthus dentatus)" width="400" /></a><br />
The above photo features the front view of a Mangrove Forceps Crab. This species is usually found hiding under driftwood or among the roots in mangrove forests. It is sometimes collected for consumption by villagers. The maximum carapace width is about 8cm.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4Uggth_lowEOveIywhIhE3W96-7QeRWNbaMJGFMqe5i_E-Mr4zZbQ-J2KODKN7P73ofJF66FI5SJu0QzM20T1yrdjgq7GeTGruiCTlrvF71YggEnUnplcbGzEngh1M7rGL13aJQ/s1600/Ozius-guttatus.jpg"><img alt="Spotted-belly Forceps Crab (Ozius guttatus)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4Uggth_lowEOveIywhIhE3W96-7QeRWNbaMJGFMqe5i_E-Mr4zZbQ-J2KODKN7P73ofJF66FI5SJu0QzM20T1yrdjgq7GeTGruiCTlrvF71YggEnUnplcbGzEngh1M7rGL13aJQ/s400/Ozius-guttatus.jpg" title="Spotted-belly Forceps Crab (Ozius guttatus)" width="400" /></a><br />
The <b>Spotted-belly Forceps Crab (<i>Ozius guttatus</i>)</b> is usually found on rocky shores, and can be easily recognised by the numerous tiny spots marking its underside. It feeds mostly on snails, and sometimes, other crustaceans. Like the previous species, it can use the curved tooth on the upper finger of the larger claw like a can-opener to cut a channel into the opening of snails, and then extract the exposed flesh with the smaller, forceps-like claw.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiK67N-JvRhCiVcabe4_HyBNPlc70dw0Z6rUpYRZ8feMoqY8mqhyphenhyphen1jvD_WkPcV_8H3PGyxfKU6A4hlx7LrE91osCBJ6fKLBFEWhHDh0hxFU-xAGGmff3jDcX8ww5kujvWZlxTJcew/s1600/Ozius-guttatus_1.jpg"><img alt="Spotted-belly Forceps Crab (Ozius guttatus)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiK67N-JvRhCiVcabe4_HyBNPlc70dw0Z6rUpYRZ8feMoqY8mqhyphenhyphen1jvD_WkPcV_8H3PGyxfKU6A4hlx7LrE91osCBJ6fKLBFEWhHDh0hxFU-xAGGmff3jDcX8ww5kujvWZlxTJcew/s400/Ozius-guttatus_1.jpg" title="Spotted-belly Forceps Crab (Ozius guttatus)" width="400" /></a><br />
The above features a Spotted-belly Forceps Crab hiding among the rocks. This species is sometimes collected by hand for consumption. The carapace can get to about 9cm wide.<br />
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<b>References</b><br />
<ul style="text-align: left;">
<li>Carpenter, K. E. & V. H. Niem (eds), 1998-2001. <i>FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific</i>. Volumes 1 to 6. FAO, Rome. pp. 1-4218.</li>
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>Ng, P. K. L., L. K. Wang & K. K. P. Lim (eds.). 2008. <i>Private Lives: An Exposé of Singapore’s Mangroves</i>. The Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 240 pp. </li>
<li>Ng, P. K. L., S. S. L. Lim, L. K. Wang & L. W. H. Tan. 2007. <i>Private lives: An exposé of Singapore's shores</i>. The Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 212 pp.</li>
<li>Vannini, M., S. Cannicci, & S. Fratini. 2001. Prey selection of Epixanthus dentatus (Crustacea: Brachyura: Eriphiidae) as determined by its prey remains.<i> Journal of the Marine Biological Association of the United Kingdom</i>, 81: 455-459. </li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
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Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com0tag:blogger.com,1999:blog-9797239.post-91998548471070873952013-07-26T17:08:00.001+08:002013-07-26T18:04:28.238+08:00Sesarmid Crabs (Phylum Arthropoda: Family Sesarmidae) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
Sesarmid crabs (phylum Arthropoda, subphylum Crustacea, class Malacostraca, order Decapoda, superfamily Grapsidoidea, family Sesarmidae) typically have a squarish carapace that is rough and covered with granules. They are often good climbers, with the tip of their legs pointed and hook-like, allowing them to easily climb up trees or mud mounds.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioYlrN3IF37QPx5auzNm7aaeYOKO8zymsXut2BfOeJ7daTXRMgTj4Y1aMR5uhWIiDIJG8Ap34Loyz6g2qmTgdKBZKhgpVjCOL_MEZzt9P25KT6H7cZ884FU4gbHcjNHBJmBmrAIA/s1600/Sesarmidae.jpg"><img alt="Sesarmid Crabs (Family Sesarmidae)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioYlrN3IF37QPx5auzNm7aaeYOKO8zymsXut2BfOeJ7daTXRMgTj4Y1aMR5uhWIiDIJG8Ap34Loyz6g2qmTgdKBZKhgpVjCOL_MEZzt9P25KT6H7cZ884FU4gbHcjNHBJmBmrAIA/s400/Sesarmidae.jpg" title="Sesarmid Crabs (Family Sesarmidae)" width="400" /></a><br />
Their "face" - the area below the eyes by the two sides of the mouthparts - is densely covered with short, stiff hair (or setae) in a network-like (reticulated) pattern. This pattern distinguishes them from <a href="http://tidechaser.blogspot.sg/2013/07/grapsid-crabs-grapsidae-singapore.html">grapsid crabs (family Grapsidae)</a>, which have stiff hairs that do not form network-like patterns. The eyes of sesarmid crabs are wide apart, situated at the two front corners of the carapace. Also, the male's abdomen rarely covers the space between the last pair of legs. They are usually found in mangroves, and feed mostly on plant materials. The inner edges of the pincers are usually quite sharp, allowing them to cut up leaves.<br />
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Sesarmid crabs are often seen moving and foraging in atmospheric air instead of in water. In order to breathe on land, they have to keep their gills wet by holding water in their gill chamber, and recirculate the water by pumping it across the hairs on their face and back to the gill chamber. As the water goes across the hairs, gas exchanges take place and the water gets re-oxygenated. <br />
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Like other true crabs, sesarmid crabs have a broad carapace, and a very short and flattened abdomen which is usually folded underneath the body. They also have five pairs of "legs" (including the clawed arms, or chelipeds), and hence they are placed in the order Decapoda ("deca" means "ten", while "poda" means "feet"). The gills are leaf-like - a distinctive characteristic of decapods from the suborder Pleocyemata. And as with other crustaceans from the class Malacostraca, their body comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head is fused to the thorax, forming a cephalothorax. They have a tough exoskeleton strengthened with calcium carbonate, and the carapace covers the gills but not the abdomen.<br />
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Sesarmid crabs reproduce sexually, and have separate sexes. They mate face-to-face, usually with the male on top and the female below. The females can usually be distinguished from the males by having a broader abdomen. This is an adaptation to allow them to carry the eggs under their abdomen until they hatch.<br />
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Here are the sesarmid crabs that I have photographed in Singapore.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhKktQqcHJPqdawf-Aiy0FIQfClI6s_D7X4xNuYrIM_jaTH5zG8Ek4Yq5dNQoA_hIiZD70gtWu_F79M_pR-at3f4d_Rt0KCK9UTPRJRbeNckHGPmcfN6yB6FE2e0cQMJXjogsIfLg/s1600/Episesarma-versicolor.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhKktQqcHJPqdawf-Aiy0FIQfClI6s_D7X4xNuYrIM_jaTH5zG8Ek4Yq5dNQoA_hIiZD70gtWu_F79M_pR-at3f4d_Rt0KCK9UTPRJRbeNckHGPmcfN6yB6FE2e0cQMJXjogsIfLg/s400/Episesarma-versicolor.jpg" width="400" /></a><br />
The <b>Violet Tree-climbing Crab (<i>Episesarma versicolor</i>)</b> is often seen up on the tree trunk and branches during high tide, probably to avoid predatory fishes. This species can be distinguished from other tree-climbing crabs by its violet palm and white fingers. It is usually found on the seaward part of mangrove forests. The maximum carapace width of this crab is about 5cm.<br />
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The various species of tree-climbing crabs are often also called vinegar crabs, as they are sometimes pickled in vinegar and dark soy sauce, and eaten with porridge by the Teochews. They mostly feed on leaves, but have been observed to scavenge sometimes. Their dull colours allow them to blend into the surrounding to avoid both aerial and terrestrial predators such as kingfishers, monitor lizards and snakes. They are sometimes considered pests in mangrove plantations, as they feed on the young leaves, shoots and seedlings.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3OOlEK119l2nZLunhQZq0Rpf5FTpo249cpP_iNx11tbrjFyFmgye6FvZvtfHUJ94Y6Hs_rYcA0WrjqWHPVrxB_eK6EoRxgqjg76TptTEJApEydpmViZ0HLZIvYFP3Zy5oon45ow/s1600/Episesarma-singaporense.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3OOlEK119l2nZLunhQZq0Rpf5FTpo249cpP_iNx11tbrjFyFmgye6FvZvtfHUJ94Y6Hs_rYcA0WrjqWHPVrxB_eK6EoRxgqjg76TptTEJApEydpmViZ0HLZIvYFP3Zy5oon45ow/s400/Episesarma-singaporense.jpg" width="400" /></a><br />
The above is probably a <b>Singapore Tree-climbing Crab (<i>Episesarma singaporense</i>)</b>, with its red claws and purple legs. There are apparently other species with red claws as well, and hence it can be hard to say for sure without closer examination of the animal physically. It is commonly found towards the landward side of mangrove forests, especially around mud lobster mounds, where it builds its burrow. The maximum carapace width of this crab is about 5cm.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6kD3TFdr8l7HI3RW-Npr4HGYEHQk1gnaCye2AebWyU-n6Z8Pfo7OmXwxrjMB9GuYUjCFoKLHZq6LaCJ7R95xFe_reiz6mbOt8Ei0HFBJ-NnwtO2-L-V4Kl4zY4mr3FyTTNGOuTg/s1600/Episesarma.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6kD3TFdr8l7HI3RW-Npr4HGYEHQk1gnaCye2AebWyU-n6Z8Pfo7OmXwxrjMB9GuYUjCFoKLHZq6LaCJ7R95xFe_reiz6mbOt8Ei0HFBJ-NnwtO2-L-V4Kl4zY4mr3FyTTNGOuTg/s400/Episesarma.jpg" width="400" /></a><br />
The identity of the above <b>Pink-fingered Tree-climbing Crab (<i>Episesarma </i>sp.)</b> is in dispute recently, awaiting a revision. This species is more commonly found on the seaward side of mangrove forests, and is easily recognised by a whitish upper finger, and a pinkish red lower finger. The maximum carapace width of this crab is about 5cm.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjvuejsZOl7VSKAGPtstvOp70C3OD96ZgeSuAkNQU-e7JOdpnGxNZAptddQ1kbcwCaqgTWA1siJEy90ULZvvSIbdujTtP9JOUyFCu1a7qKPHlxI92ndoI5dpjyANDmWkbDjDXsPzg/s1600/Selatium-brockii.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjvuejsZOl7VSKAGPtstvOp70C3OD96ZgeSuAkNQU-e7JOdpnGxNZAptddQ1kbcwCaqgTWA1siJEy90ULZvvSIbdujTtP9JOUyFCu1a7qKPHlxI92ndoI5dpjyANDmWkbDjDXsPzg/s400/Selatium-brockii.jpg" width="400" /></a>
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The <b>Mangrove Tree-dwelling Crab (<i>Selatium brockii</i>)</b> usually hides in crevices and under loose bark in the day, and emerges at night to feed on algae growing on the tree. It also feeds on leaves and small invertebrates sometimes. This species can be recognised by its greenish to brownish carapace, often with dark bands on the carapace and legs. The eyes often have a greenish tint. The carapace gets to about 2.5cm wide.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiOlY6Im1XAcSxu2e2nTWvV1eEIcOMwXE41irrztsEn3YNutiRaAnWo_yduHOxgc_PHRzA2ngWGICcwTFFbQ3-55XKLpJwKhNX6Bc6KV6Ge_QE9n0vw3llP_8IhZW-crpXWdpZBtg/s1600/Nanosesarma-batavicum.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiOlY6Im1XAcSxu2e2nTWvV1eEIcOMwXE41irrztsEn3YNutiRaAnWo_yduHOxgc_PHRzA2ngWGICcwTFFbQ3-55XKLpJwKhNX6Bc6KV6Ge_QE9n0vw3llP_8IhZW-crpXWdpZBtg/s400/Nanosesarma-batavicum.jpg" width="400" /></a><br />
The <b>Javan Mangrove Crab (<i>Nanosesarma batavicum</i>)</b> is a small crab with a rectangular carapace (maximum width about 1cm). It is often found on trees, and can be recognised by the series of small ridges lining the upperside of the top finger of its purplish pincers. It also has numerous strong teeth and spines on its legs, which help to "hook" onto the tree trunk, so that it can stay on the tree and move around effectively.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkN07Vt3b2utFvoEMY6Ve2ihGTdIt6NmdaNsrpoTiRYoYTUaSr1pABCTAd3scvm3h9fTiSwEMZmoOJuBYE3HSxlOyrtnGnygWTMRrxP6vRCaVmYS3ZGMpJba7kj40Lnuk3nSy8Kg/s1600/Perisesarma-indiarum.jpg"><img alt="Iridescent Crab (Perisesarma indiarum)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkN07Vt3b2utFvoEMY6Ve2ihGTdIt6NmdaNsrpoTiRYoYTUaSr1pABCTAd3scvm3h9fTiSwEMZmoOJuBYE3HSxlOyrtnGnygWTMRrxP6vRCaVmYS3ZGMpJba7kj40Lnuk3nSy8Kg/s400/Perisesarma-indiarum.jpg" title="Iridescent Crab (Perisesarma indiarum)" width="400" /></a><br />
The <b>Iridescent Crab (<i>Perisesarma indiarum</i>)</b> is sometimes seen in the mangrove, and can be recognised by its electric blue body, legs, face and mouthparts (the mustache like pattern below the face band). Research shows that <i>Perisesarma </i>crabs can see colours, and the colours on their faces are species specific. Scientists believe that these colours help the crabs to recognise rivals and potential mates. <i>Perisesarma </i>crabs largely feed on fallen leaves, and as they feed, small bits and pieces that are not consumed drop onto the ground, which are in turn eaten by other smaller herbivores. The carapace of this species can get to about 4cm wide.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjhZwOaPThIHWr3xI5NyluFADTdaxfn-SbALbr5D_ZWQ62LYEhyIKx82zFYlhdny4cGkVjJLvACs5pQPndWxAVezSlMihP58dbpdPGR4WX4lQpdVRWqDXmrHugoiiUmzk9xl4ELfg/s1600/Perisesarma-eumolpe.jpg"><img alt="Face-banded Crab (Perisesarma eumolpe)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjhZwOaPThIHWr3xI5NyluFADTdaxfn-SbALbr5D_ZWQ62LYEhyIKx82zFYlhdny4cGkVjJLvACs5pQPndWxAVezSlMihP58dbpdPGR4WX4lQpdVRWqDXmrHugoiiUmzk9xl4ELfg/s400/Perisesarma-eumolpe.jpg" title="Face-banded Crab (Perisesarma eumolpe)" width="400" /></a><br />
The <b>Face-banded Crab (<i>Perisesarma eumolpe</i>)</b> can be distinguished from the previous species by having black mouthparts instead of the blue ones found on the latter. The carapace can grow to about 4cm wide.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj5bQVCwD1bdcai1zxcnKluZNhKTMNdexYyi2X_hHu9cOyn7qNG26U7ULLHJhrILgPCvvuDD8Hp1MOBu-fRNXZ1RIsf0OPLxhr6q2RDZPu0reWLsnNBOPrqeMc0IqCcYY6ukA0puA/s1600/Perisesarma-dussumieri.jpg"><img alt="Dussumier's Mangrove Crab (Perisesarma dussumieri)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj5bQVCwD1bdcai1zxcnKluZNhKTMNdexYyi2X_hHu9cOyn7qNG26U7ULLHJhrILgPCvvuDD8Hp1MOBu-fRNXZ1RIsf0OPLxhr6q2RDZPu0reWLsnNBOPrqeMc0IqCcYY6ukA0puA/s400/Perisesarma-dussumieri.jpg" title="Dussumier's Mangrove Crab (Perisesarma dussumieri)" width="400" /></a><br />
The <b>Dussumier's Mangrove Crab (<i>Perisesarma dussumieri</i>)</b> is usually found in the back mangrove, especially in areas with freshwater influence. Due to this niche preference, it is generally uncommon in Singapore, since most of such habitats have been destroyed. Unlike the previous <i>Perisesarma </i>species, the band on its face is a dull cream colour. The tips of its legs are orange in colour, and there is a broad black band just above the orange tip. The carapace can grow to about 4cm wide.<br />
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<hr />
<br />
<b>References</b><br />
<ul style="text-align: left;">
<li>Carpenter, K. E. & V. H. Niem (eds), 1998-2001. <i>FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific</i>. Volumes 1 to 6. FAO, Rome. pp. 1-4218.</li>
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>Ng, P. K. L., L. K. Wang & K. K. P. Lim (eds.). 2008. <i>Private Lives: An Exposé of Singapore’s Mangroves</i>. Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 240 pp. </li>
<li>Ng, P. K. L., S. S. L. Lim, L. K. Wang & L. W. H. Tan. 2007. <i>Private lives: An exposé of Singapore's shores</i>. Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 212 pp.</li>
<li>Ng, P. K .L., R. T. Corlett & H.T.W. Tan (eds.). 2011. <i>Singapore biodiversity: An encyclopedia of the natural environment and sustainable development</i>. Singapore: Editions Didier Millet. 552 pp.</li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
</div>
Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com2tag:blogger.com,1999:blog-9797239.post-79309319426930388602013-07-26T17:03:00.001+08:002013-07-26T18:04:28.233+08:00Grapsid Crabs (Phylum Arthropoda: Family Grapsidae) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
Grapsid crabs (phylum Arthropoda, subphylum Crustacea, class Malacostraca, order Decapoda, superfamily Grapsidoidea, family Grapsidae) have squarish, rectangular, trapezoidal or circular carapaces. They can be found in mangroves or rocky shores, feeding mostly on algae and plant materials, though they sometimes also hunt small shore animals. The sharply pointed tips of their legs allow them to climb up trees and over rocks effectively.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5Tg12mlHw7BCHCHnUWLCV4VQmQNYr4YbAMHRs1Izd6CJSLpo7V2K_CU6p3NCAiqbXF-njcHOqY5g6347oSxoNPkhyxEK4rmVHQk5CdNCS_nSnGiyQESf8bqdhbq5PO2-emJlwJg/s1600/Grapsidae.jpg"><img alt="Grapsid Crabs (Family Grapsidae)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5Tg12mlHw7BCHCHnUWLCV4VQmQNYr4YbAMHRs1Izd6CJSLpo7V2K_CU6p3NCAiqbXF-njcHOqY5g6347oSxoNPkhyxEK4rmVHQk5CdNCS_nSnGiyQESf8bqdhbq5PO2-emJlwJg/s400/Grapsidae.jpg" title="Grapsid Crabs (Family Grapsidae)" width="400" /></a><br />
Grapsid crabs generally prefer to move around and forage in atmospheric air instead of in water. In order to breathe on land, they have to keep their gills wet by holding water in their gill chamber, and recirculate the water by pumping it across the hairs on their face and back to the gill chamber. As the water goes across the hairs, gas exchanges take place and the water gets re-oxygenated.<br />
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Like other true crabs, grapsid crabs have a broad carapace, and a very short and flattened abdomen which is usually folded underneath the body. They also have five pairs of "legs" (including the clawed arms, or chelipeds), and hence they are placed in the order Decapoda ("deca" means "ten", while "poda" means "feet"). The gills are leaf-like - a distinctive characteristic of decapods from the suborder Pleocyemata. And as with other crustaceans from the class Malacostraca, their body comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head is fused to the thorax, forming a cephalothorax. They have a tough exoskeleton strengthened with calcium carbonate, and the carapace covers the gills but not the abdomen.<br />
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Grapsid crabs reproduce sexually, and have separate sexes. They mate face-to-face, usually with the male on top and the female below. The females can usually be distinguished from the males by having a broader abdomen. This is an adaptation to allow them to carry the eggs under their abdomen until they hatch.<br />
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Grapsid crabs can be confused with <a href="http://tidechaser.blogspot.sg/2013/07/plagusia-plagusiid-crabs-singapore.html">plagusiids (family Plagusiidae)</a> and <a href="http://tidechaser.blogspot.sg/2013/07/climber-crabs-sesarmidae-singapore.html">sesarmid ( family Sesarmidae)</a> crabs. They can be distinguished from plagusiids by their mouthparts - the gap between the third pair of feeding appendages (or maxillipeds) is not distinctly rhomboidal, unlike those of the plagusiids. In addition, the third to fifth abdominal segments of grapsid crabs are freely movable for most species, while those of the plagusiids are fused and immovable. These features are not easy to observe in the wild, but fortunately the plagusiid species in Singapore are generally covered in small bumps, but not the local grapsid species.<br />
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The sesarmid crabs can be distinguished from the grapsid crabs by the network-like patterns form by the hair on their faces. While the grapsid crabs have the short and stiff hairs on their faces as well, they do not form the network-like patterns.<br />
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Here are the grapsid crabs that I have photographed in Singapore.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXmUzXkIWpVcX4Z9Q7g4gI9dBH7FVNOH9fQGH27x8ch3UDJYGUzAXnikqGy8zC5H9QYB23BXsg55_BUAgry7NM2fBNHn0tOKcVKn5fjGOxbODLBz6b7Lz-yb0e3D7Yci75oA6V1Q/s1600/Grapsus-albolineatus.jpg"><img alt="Sally-light-foot (Grapsus albolineatus)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXmUzXkIWpVcX4Z9Q7g4gI9dBH7FVNOH9fQGH27x8ch3UDJYGUzAXnikqGy8zC5H9QYB23BXsg55_BUAgry7NM2fBNHn0tOKcVKn5fjGOxbODLBz6b7Lz-yb0e3D7Yci75oA6V1Q/s400/Grapsus-albolineatus.jpg" title="Sally-light-foot (Grapsus albolineatus)" width="400" /></a><br />
The <b>Sally-light-foot (<i>Grapsus albolineatus</i>)</b> is usually seen on rocky shores and sea walls. This very agile climber often forages just above the waves. Its long legs with pointed tips allow them to move quickly from rock to rock. This species can be recognised by its round carapace that is marked with pale stripes. The maximum carapace width is about 5cm. It is sometimes collected by hand or nets for consumption.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgoIGkX95ZvuAckoidU6HkoJUnfcbDUbO9stHBVU-urwMgNvRxQysIsOOI6itP2WTY6PP5qbA0zrdelaTzBZZ92sPAyXNsoTiCt9xiA2KnJr_muEUFnj86_3b_jBgTCKReSIjxDVg/s1600/Metopograpsus1.jpg"><img alt="Purple Climber Crab (Metopograpsus sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgoIGkX95ZvuAckoidU6HkoJUnfcbDUbO9stHBVU-urwMgNvRxQysIsOOI6itP2WTY6PP5qbA0zrdelaTzBZZ92sPAyXNsoTiCt9xiA2KnJr_muEUFnj86_3b_jBgTCKReSIjxDVg/s400/Metopograpsus1.jpg" title="Purple Climber Crab (Metopograpsus sp.)" width="400" /></a><br />
The <b>Purple Climber Crabs (<i>Metopograpsus </i>spp.)</b> are a group of purple or purplish crabs that are commonly found on rocks and manmade structures on the seashore. They come in different patterns and different shades of purple, but it is generally hard to identify the species just by looking at the colour and pattern. They feed mostly on the algae growing on the rocks, scraping them off with their pincers. Occasionally, they also feed on other small animals on the rocky shore, such as sea slaters. The below are some examples of variations of Purple Climber Crabs, which may or may not be of the same species.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjp2Id-ynSDQMKUgdYl4FOuM8yheEoi3XnLqTrPy6DvENokOhk7lai2auOqGuomDnREiMt52gFdnqItCL7f0Ua8wiyxhPkgBTSefqTEf6gU9YFy5kbejesX6bHMDERaAcqMcKT49w/s1600/Metopograpsus.jpg"><img alt="Purple Climber Crab (Metopograpsus sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjp2Id-ynSDQMKUgdYl4FOuM8yheEoi3XnLqTrPy6DvENokOhk7lai2auOqGuomDnREiMt52gFdnqItCL7f0Ua8wiyxhPkgBTSefqTEf6gU9YFy5kbejesX6bHMDERaAcqMcKT49w/s400/Metopograpsus.jpg" title="Purple Climber Crab (Metopograpsus sp.)" width="400" /></a><br />
The above Purple Climber Crab has a black carapace marked with whitish patches.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghCiHwSr7VaowKHDhaVYVOB8Tfpt4AO6BDmZQHGdqOYNEN6N5dqzmmINp9P1coc3gpZTzuPHej86gWwV7JmOgwBZgz0dO33zKnxeaGSwfLzW87NjRm6Dmi8XfxIv8HaU0Xq2kIyA/s1600/Metopograpsus2.jpg"><img alt="Purple Climber Crab (Metopograpsus sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghCiHwSr7VaowKHDhaVYVOB8Tfpt4AO6BDmZQHGdqOYNEN6N5dqzmmINp9P1coc3gpZTzuPHej86gWwV7JmOgwBZgz0dO33zKnxeaGSwfLzW87NjRm6Dmi8XfxIv8HaU0Xq2kIyA/s400/Metopograpsus2.jpg" title="Purple Climber Crab (Metopograpsus sp.)" width="400" /></a><br />
This Purple Climber Crab is of a lighter purple, and its carapace is marked with a maze-like pattern.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2n1aKvrVO06Ldc1C0EwYj8aTmMe1Bu32XfPvZ8MP9l9Xm405haErsSWZYYK1rjLcNYj3tVY41rkPCu-bUTT4u2_j2vTbsJpQNqEoEXN_Ssc8QluBEpTgT1m_USftQsecdN-YFZg/s1600/Metopograpsus3.jpg"><img alt="Purple Climber Crab (Metopograpsus sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2n1aKvrVO06Ldc1C0EwYj8aTmMe1Bu32XfPvZ8MP9l9Xm405haErsSWZYYK1rjLcNYj3tVY41rkPCu-bUTT4u2_j2vTbsJpQNqEoEXN_Ssc8QluBEpTgT1m_USftQsecdN-YFZg/s400/Metopograpsus3.jpg" title="Purple Climber Crab (Metopograpsus sp.)" width="400" /></a><br />
For the above Purple Climber Crab, only the claws are slightly purplish, and the back of the animals is marked with patchy patterns.<br />
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<hr />
<br />
<b>References</b><br />
<ul style="text-align: left;">
<li>Carpenter, K. E. & V. H. Niem (eds), 1998-2001. <i>FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific</i>. Volumes 1 to 6. FAO, Rome. pp. 1-4218.</li>
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>Ng, P. K. L., L. K. Wang & K. K. P. Lim (eds.). 2008. <i>Private Lives: An Exposé of Singapore’s Mangroves</i>. Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 240 pp. </li>
<li>Ng, P. K. L., S. S. L. Lim, L. K. Wang & L. W. H. Tan. 2007. <i>Private lives: An exposé of Singapore's shores</i>. Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 212 pp.</li>
<li>Ng, P. K .L., R. T. Corlett & H.T.W. Tan (eds.). 2011. <i>Singapore biodiversity: An encyclopedia of the natural environment and sustainable development</i>. Singapore: Editions Didier Millet. 552 pp.</li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
</div>
Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com0tag:blogger.com,1999:blog-9797239.post-52101882353621210892013-07-26T17:00:00.001+08:002013-07-26T18:04:28.212+08:00Rafting Crabs (Phylum Arthropoda: Family Plagusiidae) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
Plagusiid crabs (phylum Arthropoda, subphylum Crustacea, class Malacostraca, order Decapoda, superfamily Grapsidoidea, family Plagusiidae) are usually found on rocky shores, and the relatively long legs allow them to move from rock to rock quickly. They feed mostly on seaweed, and occasionally small animals.<br />
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Like other true crabs, plagusiid crabs have a broad carapace, and a very short and flattened abdomen which is usually folded underneath the body. They also have five pairs of "legs" (including the clawed arms, or chelipeds), and hence they are placed in the order Decapoda ("deca" means "ten", while "poda" means "feet"). The gills are leaf-like - a distinctive characteristic of decapods from the suborder Pleocyemata. And as with other crustaceans from the class Malacostraca, their body comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head is fused to the thorax, forming a cephalothorax. They have a tough exoskeleton strengthened with calcium carbonate, and the carapace covers the gills but not the abdomen.<br />
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Plagusiid crabs reproduce sexually, and have separate sexes. They mate face-to-face, usually with the male on top and the female below. The females can usually be distinguished from the males by having a broader abdomen. This is an adaptation to allow them to carry the eggs under their abdomen until they hatch. <br />
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They are easily confused with <a href="http://tidechaser.blogspot.sg/2013/07/grapsid-crabs-grapsidae-singapore.html">grapsid crabs (family Grapsidae)</a>, except that the third to sixth segments of the abdomen are fused and immovable, while the third to fifth abdominal segments of grapsid crabs are freely movable for most species. In addition, the mouthparts are different - the gap between the third pair of feeding appendages (or maxillipeds) is not distinctly rhomboidal, unlike those of the grapsids. These differences can be hard to examine in the field, but fortunately, this family is only represented by one genus on Singapore's shore, <i>Plagusia</i>, which can be recognised by the numerous tiny bumps covering the exoskeleton. <i>Plagusia </i>crabs are commonly called Rafting Crabs as they are often found living on flotsam and even pelagic marine animals.<br />
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Two <i>Plagusia</i> species are recorded from Singapore, <i>Plagusia squamosa</i> and <i>Plagusia immaculata</i>. These two species are very similar, and the only way to tell them apart is by looking at the hairs on their legs - <i>Plagusia squamosa </i>has obvious rows of short, stiff black hairs on its legs, while in <i>Plagusia immaculata,</i> the hairs are sparse, few, hardly organised into rows or absent. There are scientists who suggest that they could be the same species, and hence I will not attempt to identify the exact species of the crabs featured in my photos below.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMJXeu_M6eCqwpz-zDWoCEubDtL1J1nUsiEYzSyv8yPwAXBgTb5sbqmTK9TCq8QOE_zB_5LJFuiHjiq8iCKx_IFmPx5v4XmsBNAl2VKtjqrfxjZ9xzBpimSJ8W-b198J2IV01yiA/s1600/Plagusia-immaculata.jpg"><img alt="Rafting Crab (Plagusia sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMJXeu_M6eCqwpz-zDWoCEubDtL1J1nUsiEYzSyv8yPwAXBgTb5sbqmTK9TCq8QOE_zB_5LJFuiHjiq8iCKx_IFmPx5v4XmsBNAl2VKtjqrfxjZ9xzBpimSJ8W-b198J2IV01yiA/s400/Plagusia-immaculata.jpg" title="Rafting Crab (Plagusia sp.)" width="400" /></a><br />
The above Rafting Crab (<i>Plagusia </i>sp.) has a purplish coloration. The carapace is about 5cm wide.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTrnimHsrI3LyIWKATAAEw7yFST9IHBSUaQBdkweZn5tofBwYLyPg9PxWsRyxbwm422C_ayh5oiWCy42Iz0Mf8ohHzrRgXkzWVdpg23yXXMxTi2P4IEVo59Lgu_4xGeQSCqYlpZQ/s1600/Plagusia-squamosa.jpg"><img alt="Rafting Crab (Plagusia sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTrnimHsrI3LyIWKATAAEw7yFST9IHBSUaQBdkweZn5tofBwYLyPg9PxWsRyxbwm422C_ayh5oiWCy42Iz0Mf8ohHzrRgXkzWVdpg23yXXMxTi2P4IEVo59Lgu_4xGeQSCqYlpZQ/s400/Plagusia-squamosa.jpg" title="Rafting Crab (Plagusia sp.)" width="400" /></a><br />
Some of the Rafting Crabs seen have a brownish coloration instead.<br />
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<hr />
<br />
<b>References</b><br />
<ul style="text-align: left;">
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>Schubart, C. D. & P. K. L. Ng. 2000. On the identities of the rafting crabs Cancer depressus Fabricius, 1775, Cancer squamosus Herbst, 1790, Plagusia immaculata Lamarck, 1818, and Plagusia tuberculata Lamarck, 1818 (Crustacea: Decapoda: Brachyura: Plagusiidae). <i>The Raffles Bulletin of Zoology</i> 48(2): 327-336.</li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
</div>
Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com0tag:blogger.com,1999:blog-9797239.post-30131204260901670902013-07-26T16:57:00.000+08:002013-07-26T18:04:28.207+08:00Varunid Crabs (Phylum Arthropoda: Family Varunidae) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
Varunid crabs (phylum Arthropoda, subphylum Crustacea, class Malacostraca, order Decapoda, superfamily Grapsidoidea, family Varunidae) typically have smooth, squarish or trapezoidal carapaces with the front margin lacking any lobes or teeth. The abdomen of the males rarely covers the whole space between the last pair of legs, and all abdominal segments are movable. These features are hard to examine on the field, and hence it is probably easier to memorise the few commonly seen species instead.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhy9_qTTsv37uhUVHkMsxfPEeEzZcUlRzLrI69ePq-T5L5usRLE6PBXjGVw76S8e0vWu3pwxpohNQXE_ObrqGyWAeGV5xanKRVmx5UqUsBALWh3L1NOVC38HPDypTJfLrNb3457Vg/s1600/Varunidae.jpg"><img alt="Varunid Crabs (Family Varunidae)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhy9_qTTsv37uhUVHkMsxfPEeEzZcUlRzLrI69ePq-T5L5usRLE6PBXjGVw76S8e0vWu3pwxpohNQXE_ObrqGyWAeGV5xanKRVmx5UqUsBALWh3L1NOVC38HPDypTJfLrNb3457Vg/s400/Varunidae.jpg" title="Varunid Crabs (Family Varunidae)" width="400" /></a><br />
Most varunid crabs live in the mangrove or mudflats, though some may also be found on drift woods and flotsam out in the sea. Some are known to be able to survive in both fresh and salt water. Their legs are broad and often lined with hair, allowing them to swim for short distances. Varunid crabs are omnivorous, and some have been observe to scavenge.<br />
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Like other true crabs, varunid crabs have a broad carapace, and a very short and flattened abdomen which is usually folded underneath the body. They also have five pairs of "legs" (including the clawed arms, or chelipeds), and hence they are placed in the order Decapoda ("deca" means "ten", while "poda" means "feet"). The gills are leaf-like - a distinctive characteristic of decapods from the suborder Pleocyemata. And as with other crustaceans from the class Malacostraca, their body comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head is fused to the thorax, forming a cephalothorax. They have a tough exoskeleton strengthened with calcium carbonate, and the carapace covers the gills but not the abdomen.<br />
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Varunid crabs reproduce sexually, and have separate sexes. They mate face-to-face, usually with the male on top and the female below. The females can usually be distinguished from the males by having a broader abdomen. This is an adaptation to allow them to carry the eggs under their abdomen until they hatch.<br />
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Here are the varunid crabs that I have photographed in Singapore.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhW14JnPg5ZWkwfjch9iOuCFGPKU21x7bxccYo9j_aVLjOsIRogBb5T6kUt4JOT3hXGiMD7gaUWhgz5CYrVQT_aC5Ee8clCaBKEZAmTNBM79kzwuBMYEHho2nEiG7WWeVxEzEbMvA/s1600/Varuna-litterata.jpg"><img alt="Paddler Crab (Varuna litterata or Varuna yui)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhW14JnPg5ZWkwfjch9iOuCFGPKU21x7bxccYo9j_aVLjOsIRogBb5T6kUt4JOT3hXGiMD7gaUWhgz5CYrVQT_aC5Ee8clCaBKEZAmTNBM79kzwuBMYEHho2nEiG7WWeVxEzEbMvA/s400/Varuna-litterata.jpg" title="Paddler Crab (Varuna litterata or Varuna yui)" width="400" /></a><br />
The <b>Paddler Crabs (<i>Varuna litterata</i> &<i>Varuna yui</i>)</b> have a smooth, squarish carapace with round corners and the legs are flattened and somewhat paddle-like. The colour can be light brown to brownish grey, sometimes with darker patterns on the carapace. Two species are recorded from Singapore, <i>Varuna litterata</i> and <i>Varuna yui</i>. These two species are very similar, and can only be distinguished by differences in the reproductive parts of the males. Generally, <i>Varuna litterata </i>prefers areas facing oceanic waters, while <i>Varuna yui </i>prefers the continental shelf waters. Both species can be found far away from the sea in freshwater, in estuarine areas, or even out in the sea on drift wood and flotsam. They are sometimes collected for consumption by villagers, either pickled in vinegar and/or salt or deep fried.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZS_0YaZkDqdQL3VY7s5CP_PbVwkKExl2JmPT4BH8jy9Ea_eyLV_FIm1XCoSaTGsomXGaEtxBkBxz92AmQQzzqzxfYlk6axboQkC3B80czABU2Va_hd7cCYUyOVEES2P4CgY9lsQ/s1600/Metaplax-elegans.jpg"><img alt="Orange Signaller Crab (Metaplax elegans)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZS_0YaZkDqdQL3VY7s5CP_PbVwkKExl2JmPT4BH8jy9Ea_eyLV_FIm1XCoSaTGsomXGaEtxBkBxz92AmQQzzqzxfYlk6axboQkC3B80czABU2Va_hd7cCYUyOVEES2P4CgY9lsQ/s400/Metaplax-elegans.jpg" title="Orange Signaller Crab (Metaplax elegans)" width="400" /></a><br />
The <b>Orange Signaller Crab (<i>Metaplax elegans</i>)</b> can be recognised by their distinctive orange claws. The claws of males are much larger than those of the females, and they wave their huge claws to attract the attention of the latter. The carapace is somewhat trapezoidal, with the front end wider than the back end. The maximum carapace width of this species is about 2cm. They are often found in large groups on mudflats and in mangrove forests during low tide. Their diet comprises mostly of worms. The above photo features a male.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwiD3CZdYcQ3k4maSuRdJquEKA84gncvwjwfLiZJJA7SmuofuiOAEjV0a6AzVeKaP1NRZsxGuBU0_xsV-10NlM7cH0lnMsvFkZ2h7fo0cuZOWQu7bQ1vRF0aV7F3tXY92d_nXq6w/s1600/Metaplax_elegans.jpg"><img alt="Orange Signaller Crab (Metaplax elegans)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwiD3CZdYcQ3k4maSuRdJquEKA84gncvwjwfLiZJJA7SmuofuiOAEjV0a6AzVeKaP1NRZsxGuBU0_xsV-10NlM7cH0lnMsvFkZ2h7fo0cuZOWQu7bQ1vRF0aV7F3tXY92d_nXq6w/s400/Metaplax_elegans.jpg" title="Orange Signaller Crab (Metaplax elegans)" width="400" /></a><br />
The female Orange Signaller Crab has much smaller claws.<br />
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<b>References</b><br />
<ul style="text-align: left;">
<li>Carpenter, K. E. & V. H. Niem (eds), 1998-2001. <i>FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific</i>. Volumes 1 to 6. FAO, Rome. pp. 1-4218.</li>
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>Ng, P. K. L. & N. Sivasothi (eds.), 1999. <i>A guide to the mangroves of Singapore II: animal diversity</i>. Singapore Science Centre. 168p.</li>
<li>Ng, P. K .L., R. T. Corlett & H.T.W. Tan (eds.). 2011. <i>Singapore biodiversity: An encyclopedia of the natural environment and sustainable development</i>. Singapore: Editions Didier Millet. 552 pp.</li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
</div>
Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com0tag:blogger.com,1999:blog-9797239.post-12059645203856437892013-07-26T16:56:00.000+08:002013-07-26T18:04:28.198+08:00Sentinel Crabs (Phylum Arthropoda: Family Macrophthalmidae) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
Sentinel crabs (phylum Arthropoda, subphylum Crustacea, class Malacostraca, order Decapoda, superfamily Ocypodoidea, family Macrophthalmidae) can usually be recognised by their extremely long and thin eyestalks. The carapace is usually quadrilateral, broader than long, and lined with teeth by the sides. The chelipeds are somewhat equal in size.<br />
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They are usually found on soft substrates, such as mud and sand. The long eyestalks allow them to see all around (even behind), so that they can quickly burrow into the soft substrate to hide from predator. They feed on tiny decaying organic materials (or detritus) and small invertebrates. These crabs often build burrows with a distinctive opening - either rectangular or ovate in shape.<br />
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Like other true crabs, sentinel crabs have a broad carapace, and a very short and flattened abdomen which is usually folded underneath the body. They also have five pairs of "legs" (including the clawed arms, or chelipeds), and hence they are placed in the order Decapoda ("deca" means "ten", while "poda" means "feet"). The gills are leaf-like - a distinctive characteristic of decapods from the suborder Pleocyemata. And as with other crustaceans from the class Malacostraca, their body comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head is fused to the thorax, forming a cephalothorax. They have a tough exoskeleton strengthened with calcium carbonate, and the carapace covers the gills but not the abdomen.<br />
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Sentinel crabs reproduce sexually, and have separate sexes. They mate face-to-face, usually with the male on top and the female below. The females can usually be distinguished from the males by having a broader abdomen. This is an adaptation to allow them to carry the eggs under their abdomen until they hatch.<br />
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Here are the sentinel crabs that I have photographed in Singapore, but unfortunately, I have not been able to identify them to the species.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2H5Ebxm1zrH1JkBadrrV8CEfoTpVaIBeG3wif8s969fYwdV43QlZ9qjtsNTulFDv1JvP0EIOJ5nGDcIqGj3XIdjefR9AlmZkbTh37ww0vnL2V3oYijhWoyGXU9c4LgcUMNawMyg/s1600/Macrophthalmus4.jpg"><img alt="Sentinel Crab (Macrophthalmus sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2H5Ebxm1zrH1JkBadrrV8CEfoTpVaIBeG3wif8s969fYwdV43QlZ9qjtsNTulFDv1JvP0EIOJ5nGDcIqGj3XIdjefR9AlmZkbTh37ww0vnL2V3oYijhWoyGXU9c4LgcUMNawMyg/s400/Macrophthalmus4.jpg" title="Sentinel Crab (Macrophthalmus sp.)" width="400" /></a><br />
This fairly big <b>Sentinel Crab (<i>Macrophthalmus </i>sp.)</b> has a bluish grey carapace of about 5cm wide. There are several spines on its chelipeds. It was found on a sand bar next to a seagrass meadow.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_2ISeNHa5OOm4eUFaUA5bmApEXjLiDpQriH2SKy2CgTldsXoSgguu8hoT2NyApsaHjgdcSLnY_a-0Zsshd9R_Hctwd0b0t8EeuvExsL7XoFynWfre_EzPgzBrlvAw5pD4LNm1iw/s1600/Macrophthalmus.jpg"><img alt="Sentinel Crab (Macrophthalmus sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_2ISeNHa5OOm4eUFaUA5bmApEXjLiDpQriH2SKy2CgTldsXoSgguu8hoT2NyApsaHjgdcSLnY_a-0Zsshd9R_Hctwd0b0t8EeuvExsL7XoFynWfre_EzPgzBrlvAw5pD4LNm1iw/s400/Macrophthalmus.jpg" title="Sentinel Crab (Macrophthalmus sp.)" width="400" /></a><br />
This <b>Sentinel Crab (<i>Macrophthalmus </i>sp.)</b> has a pale brownish grey carapace which is about 3cm wide. It was found on coarse sand mixed with broken shells.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhef2s_NPTDwskASaJvEK1prbxpjo6xX606VeHKmS7DqeXL_XkB52ISlueBmOuAzEg7ZAh3mnCbYrvLTkEomDIwdUJXHyamZFiGXXjlhNNU1wTHMBUkNWIHMWtr8ZoNatvbeO9cxw/s1600/Macrophthalmus3.jpg"><img alt="Sentinel Crab (Macrophthalmus sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhef2s_NPTDwskASaJvEK1prbxpjo6xX606VeHKmS7DqeXL_XkB52ISlueBmOuAzEg7ZAh3mnCbYrvLTkEomDIwdUJXHyamZFiGXXjlhNNU1wTHMBUkNWIHMWtr8ZoNatvbeO9cxw/s400/Macrophthalmus3.jpg" title="Sentinel Crab (Macrophthalmus sp.)" width="400" /></a><br />
The above <b>Sentinel Crab (<i>Macrophthalmus </i>sp.)</b> may resemble the previous species, but the carapace (about 3cm wide) is not plain but covered in darker markings. It was found on coarse sand.<br />
<br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhB6CjnuwpOzxUD3UdV5N6bUjGgWjfeN2unUnpknTcTnx628qiURMfKKthtyzJshlrzzA5jG76dFSmM2nGUVe_YqYCUmkGXOar5W5yi62Oh9V7a8FYcWYvbM-hSkaXugDupzGqxiA/s1600/Macrophthalmus2.jpg"><img alt="Sentinel Crab (Macrophthalmus sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhB6CjnuwpOzxUD3UdV5N6bUjGgWjfeN2unUnpknTcTnx628qiURMfKKthtyzJshlrzzA5jG76dFSmM2nGUVe_YqYCUmkGXOar5W5yi62Oh9V7a8FYcWYvbM-hSkaXugDupzGqxiA/s400/Macrophthalmus2.jpg" title="Sentinel Crab (Macrophthalmus sp.)" width="400" /></a><br />
This small <b>Sentinel Crab (<i>Macrophthalmus </i>sp.)</b> has a greyish carapace (about 2cm wide) marked with black patterns. <br />
<br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjmzgyXx1brWyYIkZB_OHUcrxFweOq_KUCBCOC-JxYl0YCFw_gWvDuuXlHdmuXpKGyYWxPBGrYUMcoPj0c6Z-JR-Ho8M_H-wTLkxaal1vPR1qF34yB2hotXYYOzPkHpIYaFyjna8w/s1600/Macrophthalmus1.jpg"><img alt="Sentinel Crab (Macrophthalmus sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjmzgyXx1brWyYIkZB_OHUcrxFweOq_KUCBCOC-JxYl0YCFw_gWvDuuXlHdmuXpKGyYWxPBGrYUMcoPj0c6Z-JR-Ho8M_H-wTLkxaal1vPR1qF34yB2hotXYYOzPkHpIYaFyjna8w/s400/Macrophthalmus1.jpg" title="Sentinel Crab (Macrophthalmus sp.)" width="400" /></a><br />
The above <b>Sentinel Crabs (<i>Macrophthalmus </i>sp.)</b> were seen in a muddy seagrass meadow. The body is mostly orange, and the chelipeds are white. The carapace is about 3cm wide.<br />
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<b>References</b><br />
<ul style="text-align: left;">
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>ETI BioInformatics. 2012. <i>Marine species identification portal</i>. Retrieved Jul 8, 2013, from http://species-identification.org.</li>
<li>Mendoza, J. C. E. & P. K. L. Ng, 2007. Macrophthalmus (Euplax) H. Milne Edwards, 1852, a valid subgenus of ocypodoid crab (Decapoda: Brachyura: Macrophthalmidae), with description of a new species from the Philippines. <i>Journal of Crustacean Biology</i>, 27(4): 670–680.</li>
<li>Ng, P. K. L., S. S. L. Lim, L. K. Wang & L. W. H. Tan. 2007. <i>Private lives: An exposé of Singapore's shores</i>. Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 212 pp.</li>
<li>Ng, P. K .L., R. T. Corlett & H.T.W. Tan (eds.). 2011. <i>Singapore biodiversity: An encyclopedia of the natural environment and sustainable development</i>. Singapore: Editions Didier Millet. 552 pp.</li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
</div>
Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com0tag:blogger.com,1999:blog-9797239.post-54803476686805034122013-07-26T16:53:00.002+08:002013-07-26T18:04:28.215+08:00Sand Bubbler & Soldier Crabs (Phylum Arthropoda: Family Dotillidae) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
Dotillid crabs (phylum Arthropoda, subphylum Crustacea, class Malacostraca, order Decapoda, superfamily Ocypodoidea, Family Dotillidae) are typically small crabs with rounded carapaces.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhd_27MK-ZDhxplONATAhhU4Xm4-qlIuN19I0d1F_P0iK7SfN7XS0v2njC-9JCzVw-OqIpIWXvWrLRNUYCVcZZGxMswyrnT15nOSbXo65Yweixjy7tR0y9y-5UDWDxTUu-3Vz04_g/s1600/Dotillidae.jpg"><img alt="Dotillid Crabs (Family Dotillidae)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhd_27MK-ZDhxplONATAhhU4Xm4-qlIuN19I0d1F_P0iK7SfN7XS0v2njC-9JCzVw-OqIpIWXvWrLRNUYCVcZZGxMswyrnT15nOSbXo65Yweixjy7tR0y9y-5UDWDxTUu-3Vz04_g/s400/Dotillidae.jpg" title="Dotillid Crabs (Family Dotillidae)" width="400" /></a><br />
Their eyestalks are elongate, giving them a good view of the surrounding, so that they can quickly burrow into the soft substrate to hide from predators. They are usually found on sandy or muddy upper shores, hiding in their burrows during high tide, and emerge only during low tide to feed. Dotillid crabs are typical deposit feeders, and feed on the detritus (i.e. tiny decaying organic matter) deposited on the substrate.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjdaE5eqoi1UhL2eUJ9MGxPEKU1nITk0wSPFFlQR1LZzyGzqFU6RS6z5v-mC7WufMf_HztA_D-p7fEBlmjK-hkgjaw1RBLQ0QzlNAD3lx05UnUYTmZmQhST-kdWQpEq7Qk1rGzHJQ/s1600/Scopimera.jpg"><img alt="Sand Bubbler Crab (Scopimera intermedia)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjdaE5eqoi1UhL2eUJ9MGxPEKU1nITk0wSPFFlQR1LZzyGzqFU6RS6z5v-mC7WufMf_HztA_D-p7fEBlmjK-hkgjaw1RBLQ0QzlNAD3lx05UnUYTmZmQhST-kdWQpEq7Qk1rGzHJQ/s400/Scopimera.jpg" title="Sand Bubbler Crab (Scopimera intermedia)" width="400" /></a><br />
They will put the sand into their mouthparts to extract the layer of detritus covering the sand grains, and then push the cleansed sand grains out of the mouthparts to be gathered into a sand ball.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiNFLN8EQP_AlfP1drU1Ji3os7udYa_iJTBykcgtmk5Yzt4Lb_J0cpvUf1UTV-YUea_jQmwhwVQdhyphenhyphenfbg7tbVumr926tAqNe0vo7jQRSCybcWNe_h4QiQPbprv52O7sQ-CXlp4vxQ/s1600/Scopimera1.jpg"><img alt="Sand Bubbler Crab (Scopimera intermedia)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiNFLN8EQP_AlfP1drU1Ji3os7udYa_iJTBykcgtmk5Yzt4Lb_J0cpvUf1UTV-YUea_jQmwhwVQdhyphenhyphenfbg7tbVumr926tAqNe0vo7jQRSCybcWNe_h4QiQPbprv52O7sQ-CXlp4vxQ/s400/Scopimera1.jpg" title="Sand Bubbler Crab (Scopimera intermedia)" width="400" /></a><br />
Eventually when the sand ball gets too big, the crab will toss the sand ball aside.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhAdQlKMtGKNo_6UCjyxKKN0h5CS_-aBSYlNytHmwOOARDhD14TfjGhJboKfcS_PLhjaEqJ20s09f7B1RzZ7i3kvKeEjdM9mhs7I0l7SDNAr3BA9ptTtyWbwZlOIg6T65QfKa_YNA/s1600/Scopimera1.jpg"><img alt="Sand balls made by Sand Bubbler Crab (Scopimera intermedia)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhAdQlKMtGKNo_6UCjyxKKN0h5CS_-aBSYlNytHmwOOARDhD14TfjGhJboKfcS_PLhjaEqJ20s09f7B1RzZ7i3kvKeEjdM9mhs7I0l7SDNAr3BA9ptTtyWbwZlOIg6T65QfKa_YNA/s400/Scopimera1.jpg" title="Sand balls made by Sand Bubbler Crab (Scopimera intermedia)" width="400" /></a><br />
The numerous tiny sand balls found on sandy beaches are usually made by dotillid crabs. The bigger sand balls are the sand excavated by the crab while building its burrow, while the smaller ones are the discarded sand balls from its feeding activities.<br />
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Like other true crabs, dotillid crabs have a broad carapace, and a very short and flattened abdomen which is usually folded underneath the body. They also have five pairs of "legs" (including the clawed arms, or chelipeds), and hence they are placed in the order Decapoda ("deca" means "ten", while "poda" means "feet"). The gills are leaf-like - a distinctive characteristic of decapods from the suborder Pleocyemata. And as with other crustaceans from the class Malacostraca, their body comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head is fused to the thorax, forming a cephalothorax. They have a tough exoskeleton strengthened with calcium carbonate, and the carapace covers the gills but not the abdomen.<br />
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Dotillid crabs reproduce sexually, and have separate sexes. They mate face-to-face, usually with the male on top and the female below. The females can usually be distinguished from the males by having a broader abdomen. This is an adaptation to allow them to carry the eggs under their abdomen until they hatch.<br />
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Here are the dotillid crabs that I have photographed in Singapore.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQMQWIvjyx9OUqLaggqKvut5OkSqNw1-6c0NQRONbEz7IKpgIC5Yq-n5NKrTeZkpT1rzOz9EZhgw7-j05fCEsxvG_X3N6m_Y2A3PM-gJLYxHry1y3KnJ3EJtynpI5uCL2G9B1H3w/s1600/Dotilla-myctiroides.jpg"><img alt="Soldier Crabs (Dotilla myctiroides)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQMQWIvjyx9OUqLaggqKvut5OkSqNw1-6c0NQRONbEz7IKpgIC5Yq-n5NKrTeZkpT1rzOz9EZhgw7-j05fCEsxvG_X3N6m_Y2A3PM-gJLYxHry1y3KnJ3EJtynpI5uCL2G9B1H3w/s400/Dotilla-myctiroides.jpg" title="Soldier Crabs (Dotilla myctiroides)" width="400" /></a><br />
The <b>Soldier Crabs (<i>Dotilla myctiroides</i>)</b> are more easily recognised by their behaviour - they usually move around in large groups like a troop of soldiers during low tide. This species often inhibits muddier sand banks. They have a round body with relatively long legs and chelipeds. The carapace grows to a maximum width of about 1.5cm.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhn8pg9ZL8ZVFG5Wn_GdEYeC8Z2LUoGBLnWpSkcZ3KeN7KmjWCPvOEVBEj0CfjPgnHkH5ASG5KRbf2_M2PfXljHZpqraMKmtXzbrstp-sE8wNTC4-n2vrjr8skfSpIcnV9fT4bhGA/s1600/Dotilla-wichmani.jpg"><img alt="Wichman's Soldier Crab (Dotilla wichmani)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhn8pg9ZL8ZVFG5Wn_GdEYeC8Z2LUoGBLnWpSkcZ3KeN7KmjWCPvOEVBEj0CfjPgnHkH5ASG5KRbf2_M2PfXljHZpqraMKmtXzbrstp-sE8wNTC4-n2vrjr8skfSpIcnV9fT4bhGA/s400/Dotilla-wichmani.jpg" title="Wichman's Soldier Crab (Dotilla wichmani)" width="400" /></a><br />
The <b>Wichman's Soldier Crab (<i>Dotilla wichmani</i>)</b> prefers sandier areas, and does not wander far from its burrow. It is smaller than the previous species, with a maximum carapace width of about 1cm. The two species are generally hard to tell apart in the field other than by observing their behaviour.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh6jrGjvEBIe5moPLzXAWJEjhJ2UDV9hfkoyVo4uz7J8HMsHqxysLfQxSO-YeVnUbtEXv24B2xLilF9SmRMCTurso8qr-_5aAoATSXAZn9mUvAD5CpQSPR2GJ-Qqrqk3za4f-uX0Q/s1600/Scopimera-intermedia.jpg"><img alt="Sand Bubbler Crab (Scopimera intermedia)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh6jrGjvEBIe5moPLzXAWJEjhJ2UDV9hfkoyVo4uz7J8HMsHqxysLfQxSO-YeVnUbtEXv24B2xLilF9SmRMCTurso8qr-_5aAoATSXAZn9mUvAD5CpQSPR2GJ-Qqrqk3za4f-uX0Q/s400/Scopimera-intermedia.jpg" title="Sand Bubbler Crab (Scopimera intermedia)" width="400" /></a><br />
The <b>Sand Bubbler Crabs (<i>Scopimera </i>spp.)</b> are very tiny, and the carapace seldom exceeds 1cm wide. Recent studies suggest that there is probably only one species in Singapore - <b><i>Scopimera intermedia</i></b>, as featured in the above photo. This species has long and slender fingers, unlike others which usually have an obvious tooth in on the inner edge of the upper finger.<br />
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<b>References</b><br />
<ul style="text-align: left;">
<li>Carpenter, K. E. & V. H. Niem (eds), 1998-2001. <i>FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific</i>. Volumes 1 to 6. FAO, Rome. pp. 1-4218.</li>
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>Debelius, H. 1999. <i>Crustacea - Guide of the world</i>. IKAN, Frankfurt. 321pp.</li>
<li>ETI BioInformatics. 2012. <i>Marine species identification portal</i>. Retrieved Jul 8, 2013, from http://species-identification.org.</li>
<li>Ng, P. K. L., L. K. Wang & K. K. P. Lim (eds.). 2008. <i>Private lives: An exposé of Singapore’s mangroves</i>. Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 240 pp.</li>
<li>Ng, P. K. L. & N. Sivasothi (eds.), 1999. <i>A guide to the mangroves of Singapore II: animal diversity</i>. Singapore Science Centre. 168p.</li>
<li>Ng, P. K .L., R. T. Corlett & H.T.W. Tan (eds.). 2011. <i>Singapore biodiversity: An encyclopedia of the natural environment and sustainable development</i>. Singapore: Editions Didier Millet. 552 pp.</li>
<li>Ng, P. K. L., S. S. L. Lim, L. K. Wang & L. W. H. Tan. 2007. <i>Private lives: An exposé of Singapore's shores</i>. Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 212 pp.</li>
<li>Tan, L. W. H. & P. K. L. Ng. 1988. <i>A Guide to Seashore Life</i>. Singapore Science Centre. Singapore. 160 pp.</li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
</div>
Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com0tag:blogger.com,1999:blog-9797239.post-72303574333494161432013-07-26T16:49:00.000+08:002013-07-26T18:04:28.230+08:00Ocypodid Crabs (Phylum Arthropoda: Family Ocypodidae) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
Ocypodid crabs (phylum Arthropoda, subphylum Crustacea, class Malacostraca, order Decapoda, superfamily Ocypodoidea, family Ocypodidae) typically have long eyestalks, but are usually not as long or as narrow as the ones found in the previous related family. The carapace may be squarish, rectangular or trapezoidal, and many species have a lobe at the front between the bases of the eyestalks. The chelipeds (i.e. the clawed arms) are usually unequal-sized, especially in the males of some species, whereby one chelilped is much larger than the other.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkvDOlERdmUKNkAQWfGJ55vWK0uCOhw7CQhtq9IpWqjbaKOpjX_obmlUPOHIjC5msIk0eeJ7QO6KcQ2pauhvdL6BvmdFlZFny72xUN_-_peR4D1h25o1rT0FvE5Z1VZvrTAeu0OA/s1600/Ocypodidae.jpg"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkvDOlERdmUKNkAQWfGJ55vWK0uCOhw7CQhtq9IpWqjbaKOpjX_obmlUPOHIjC5msIk0eeJ7QO6KcQ2pauhvdL6BvmdFlZFny72xUN_-_peR4D1h25o1rT0FvE5Z1VZvrTAeu0OA/s400/Ocypodidae.jpg" width="400" /></a><br />
Ocypodid crabs are usually found on sandy or muddy substrates, hiding in their burrows with trapped pockets of air when the tide is high, and emerge only during low tide to feed. Some species feed mainly on detritus, while other scavenge or actively hunt for prey.<br />
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The long eyestalks allow them to see all around (even behind), so that they can quickly burrow into the soft substrate to hide from predators. Their diet comprise mostly of tiny decaying organic materials (or detritus) or other small invertebrates. They often build burrows with a distinctive opening - either rectangular or ovate in shape.<br />
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Like other true crabs, ocypodid crabs have a broad carapace, and a very short and flattened abdomen which is usually folded underneath the body. They also have five pairs of "legs" (including the clawed arms, or chelipeds), and hence they are placed in the order Decapoda ("deca" means "ten", while "poda" means "feet"). The gills are leaf-like - a distinctive characteristic of decapods from the suborder Pleocyemata. And as with other crustaceans from the class Malacostraca, their body comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head is fused to the thorax, forming a cephalothorax. They have a tough exoskeleton strengthened with calcium carbonate, and the carapace covers the gills but not the abdomen.<br />
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Ocypodid crabs reproduce sexually, and have separate sexes. They mate face-to-face, usually with the male on top and the female below. The females can usually be distinguished from the males by having a broader abdomen. This is an adaptation to allow them to carry the eggs under their abdomen until they hatch.<br />
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Here are the ocypodid crabs that I have photographed in Singapore.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKIP8Bi2YCYuOlnfbVI_34P8SGtClC67zHl0CAnFSlJEmn46G88jCzvLTU4VCL0-5csXKd66j5w_nQ8tjVmKt6_ID50zX9wE_ZGXDkixhN7dvzkd4pvWZbyimyiSoAU_1eIYtIzw/s1600/Ocypode-ceratophthalmus.jpg"><img alt="Horned Ghost Crab (Ocypode ceratophthalmus)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKIP8Bi2YCYuOlnfbVI_34P8SGtClC67zHl0CAnFSlJEmn46G88jCzvLTU4VCL0-5csXKd66j5w_nQ8tjVmKt6_ID50zX9wE_ZGXDkixhN7dvzkd4pvWZbyimyiSoAU_1eIYtIzw/s400/Ocypode-ceratophthalmus.jpg" title="Horned Ghost Crab (Ocypode ceratophthalmus)" width="400" /></a><br />
The <b>Horned Ghost Crab (<i>Ocypode ceratophthalmus</i>)</b> can be recognised by the long eyestalks which extend beyond the eye, appearing like a pair of pointed horns. While it scavenges when there are dead animals around, it is also a fierce predator, hunting other small animals like crabs and baby turtles. It is a very fast runner and often disappears in a flash when disturbed. The fast movements, in addition to its pale coloration and nocturnal habits, give this group of crabs the common name of ghost crabs.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMLtck85gIxqFy5hQsX4uaE9vPCobMsWhqdkCMhjDr-vsR9Low9oyKyJCvGX9g_nTvp9QfiRboxG1lGLcJ_I_tu0Xg8T3cj_IwYc2WuqbewXmsaEnxkLGxVWo_44JNGILloN9QKw/s1600/Ocypode_ceratophthalmus.jpg"><img alt="Horned Ghost Crab (Ocypode ceratophthalmus)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMLtck85gIxqFy5hQsX4uaE9vPCobMsWhqdkCMhjDr-vsR9Low9oyKyJCvGX9g_nTvp9QfiRboxG1lGLcJ_I_tu0Xg8T3cj_IwYc2WuqbewXmsaEnxkLGxVWo_44JNGILloN9QKw/s400/Ocypode_ceratophthalmus.jpg" title="Horned Ghost Crab (Ocypode ceratophthalmus)" width="400" /></a><br />
The Horned Ghost Crab usually builds its burrow on the high shore, and moves around during low tide. It still needs water to breathe though, and has to go into the water regularly to wet its gills. The burrows are often Y-shaped with one main entrance, while the other end is unopened with about 1cm of sand on top. When disturbed, the crab will bash through the sand at the top of the unopened end and use it as an emergency exit. This species is sometimes collected for consumption.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhOuXcF97QnYJCfy5eZVcw74r2GCVCFD-FyI5LkH9Q1hK4XI4-XnHQZH-R2sayxntOHfM1KjFt3zcxQgKw1GPWmbaa43YAMPYCWinm3Zsz6_Ar6f6QSino6LKnQKOGwSw1pPsDb1Q/s1600/Ocypode.jpg"><img alt="Horned Ghost Crab (Ocypode ceratophthalmus)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhOuXcF97QnYJCfy5eZVcw74r2GCVCFD-FyI5LkH9Q1hK4XI4-XnHQZH-R2sayxntOHfM1KjFt3zcxQgKw1GPWmbaa43YAMPYCWinm3Zsz6_Ar6f6QSino6LKnQKOGwSw1pPsDb1Q/s400/Ocypode.jpg" title="Horned Ghost Crab (Ocypode ceratophthalmus)" width="400" /></a><br />
The above is probably a juvenile Horned Ghost Crab, which has not develop the "horns" yet. The carapace has a mottled pattern, possible to allow it to camouflage better with the surrounding sand.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEig5HMIfQSjw56YWad1ft2fMdjnOpul6JGYSwdsWpSlEC1jZuShQOicOtNIj-PhZI7zG31TAobHwdVAtm9u8hPFqq-UYR5q5yeVJfOENnXiHjPqoVnZCO2WbSOGdO3PTu_hJl8tSA/s1600/Uca-forcipata.jpg"><img alt="Forceps Fiddler Crab (Uca forcipata)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEig5HMIfQSjw56YWad1ft2fMdjnOpul6JGYSwdsWpSlEC1jZuShQOicOtNIj-PhZI7zG31TAobHwdVAtm9u8hPFqq-UYR5q5yeVJfOENnXiHjPqoVnZCO2WbSOGdO3PTu_hJl8tSA/s400/Uca-forcipata.jpg" title="Forceps Fiddler Crab (Uca forcipata)" width="400" /></a><br />
The fiddler crabs (<i>Uca </i>spp.) are a prominent group of ocypodid crabs commonly found on seashores. This group of crabs are characterised by the males having unequal chelipeds - one cheliped is so much larger than the other, to the extent that they appear as if they only have one huge cheliped. Only the small cheliped is used for feeding - the crab will pick up the soil and putting it into its mouthparts, feed on the layer of detritus coating the sand and mud, and then discard the inedible bits. The constant action of moving its small cheliped up and down with the big cheliped remaining relatively still resembles the actions of playing a fiddle, and hence they were given the common name of fiddler crabs. The huge claw is used mainly for waving to the females (i.e. for courtship purposes) and to ward off competing males.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgrvelwYWwOww2Xbs5A81YYyEZG-stXr2A-ZkqZlppS9ilcletLUQ7-RpWM0AfFrWsWSoUP3EF8e4TZi-1wpPlm4gvbjhxxJeBsHb4w03QkLT1vBssC6tEnyC9KOcabYVD8kqM4Rg/s1600/Uca.jpg"><img alt="Female Fiddler Crab (Uca sp.)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgrvelwYWwOww2Xbs5A81YYyEZG-stXr2A-ZkqZlppS9ilcletLUQ7-RpWM0AfFrWsWSoUP3EF8e4TZi-1wpPlm4gvbjhxxJeBsHb4w03QkLT1vBssC6tEnyC9KOcabYVD8kqM4Rg/s400/Uca.jpg" title="Female Fiddler Crab (Uca sp.)" width="400" /></a><br />
The female fiddler crab has two small equal-sized chelipeds. As a result, it can eat faster than the males. This is especially important as the female needs to perform the energy-consuming task of laying eggs.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZAwdGAM_nr7vliStELKYkYFbOKU2JwUcDtjdgcG3DYDm6OCSTpQigw6popplQFDCGOcccEBnB-ZupCC0aZ8GgIwSUvHLxshDFZTn3HHMHNv474xbQcmCRSr-d2IX4WhkAHNQcyg/s1600/Uca_forcipata.jpg"><img alt="Forceps Fiddler Crab (Uca forcipata)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZAwdGAM_nr7vliStELKYkYFbOKU2JwUcDtjdgcG3DYDm6OCSTpQigw6popplQFDCGOcccEBnB-ZupCC0aZ8GgIwSUvHLxshDFZTn3HHMHNv474xbQcmCRSr-d2IX4WhkAHNQcyg/s400/Uca_forcipata.jpg" title="Forceps Fiddler Crab (Uca forcipata)" width="400" /></a><br />
The <b>Forceps Fiddler Crab (<i>Uca forcipata</i>) </b>can usually be distinguished from most other species by looking at its larger pincer - there is a gape in the middle between the upper and lower fingers, but the inner edges level out towards the tip, becoming somewhat parallel, giving the pincer a forceps-like appearance. The maximum carapce size of this species is about 3cm. Another species, <i>Uca rosea</i>, has similar pincers, but is slightly smaller (about 2cm wide) and usually have rose-coloured pincers, though it is usually best to check the reproductive parts to confirm the identity. The colour of the Forceps Fiddler Crab is rather variable, ranging from brownish to bluish, depending on its diet. The females of this species are known to build a chimney-like mud structure on top of its burrow, possibly to avoid detection of the burrow by potential predators. This species is usually found more inland towards the back mangrove, often along mud banks of tidal rivers.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgPKEknJy3OLt5NtiSYztFtyqx3u1zjzJ_ZXdC3mnLEVSFlZ0Jf59cl_JLt51LD3f1IXp-SmhxR8-qT8C6mcl5x-iUZEot_Q0UV3MuvRMrFIQ_ErCE7XLIgf7dDQWGrVX_LKIYJ8Q/s1600/Uca-rosea.jpg"><img alt="Rose Fiddler Crab (Uca rosea)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgPKEknJy3OLt5NtiSYztFtyqx3u1zjzJ_ZXdC3mnLEVSFlZ0Jf59cl_JLt51LD3f1IXp-SmhxR8-qT8C6mcl5x-iUZEot_Q0UV3MuvRMrFIQ_ErCE7XLIgf7dDQWGrVX_LKIYJ8Q/s400/Uca-rosea.jpg" title="Rose Fiddler Crab (Uca rosea)" width="400" /></a><br />
The above is possibly a <b>Rose Fiddler Crab (<i>Uca rosea</i>)</b>, though it is usually best to check the reproductive parts to distinguish it from the previous species. While in some specimens there may be a teeth around the middle of one or both of the upper and lower fingers, the inner edges level out towards the tip, giving it a forceps-like appearance. This species is usually reddish in colour, and the carapace gets to about 2cm wide. It is usually found towards the back mangrove, sometimes along mud banks of tidal rivers.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtp8SvG4rZzkWRDtOpKjl1hNPDiOA4jot0PC0Zzs5vt2O3FYw3-ra-urzOsDcG1WstMu8HDaXT9mEWwEBry7p5-Aqv9pgFQnqBvfeB43Xxief4ZDQcA_fVCD6-nsHAVhKKX2rkmg/s1600/Uca-annulipes.jpg"><img alt="Porcelain Fiddler Crab (Uca annulipes)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtp8SvG4rZzkWRDtOpKjl1hNPDiOA4jot0PC0Zzs5vt2O3FYw3-ra-urzOsDcG1WstMu8HDaXT9mEWwEBry7p5-Aqv9pgFQnqBvfeB43Xxief4ZDQcA_fVCD6-nsHAVhKKX2rkmg/s400/Uca-annulipes.jpg" title="Porcelain Fiddler Crab (Uca annulipes)" width="400" /></a><br />
The <b>Porcelain Fiddler Crab (<i>Uca annulipes</i>)</b> can be recognised by the irregular brown to black horizontal streaks on its carapace. In addition, the outer surface of the pincers is relatively smooth. The upper finger of the big cheliped is curved and hook-like towards the tip, while the lower finger looks truncated at the tip. This species is usually seen toward the seaward side of mangroves and on sandy mudflats. The maximum carapace width is about 2cm.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhSmUt-ImTvLJdzZaLf1Iyn-lNjL4Vd9UgpOpISxguCYTJInBd73g_i99DQOoeRHnWrL09T0QP5hGJyYs-6PLBaL5O-nrOZxFcm7zHDRKZlp_hedNzfevLzbz8-Iz6btFItjwzYJw/s1600/Uca-vocans.jpg"><img alt="Orange Fiddler Crabs (Uca vocans)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhSmUt-ImTvLJdzZaLf1Iyn-lNjL4Vd9UgpOpISxguCYTJInBd73g_i99DQOoeRHnWrL09T0QP5hGJyYs-6PLBaL5O-nrOZxFcm7zHDRKZlp_hedNzfevLzbz8-Iz6btFItjwzYJw/s400/Uca-vocans.jpg" title="Orange Fiddler Crabs (Uca vocans)" width="400" /></a><br />
The <b>Orange Fiddler Crabs (<i>Uca vocans</i>)</b> usually have orange to reddish chelipeds. The outer surface of the big cheliped is covered in small granules, and the fingers are compressed, appearing like blades. The colour of the carapace can be quite variable, ranging from dull colours such as grey and green to brighter tones like blue. Sometimes, it may have pales spots on the back of the carapace. This species is usually found on sandy mudflats, such as in sheltered bays or lagoons, or at the seaward side of mangroves. The maximum carapace width is about 2.5cm.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhfkMfPv_YjkojPWJqeW_Ujnym-qOBtsKwwEwsnpiiN9W8hoXpz7HIIIO3dFGJsncgQ2XJtLEFCeoy2a1fRuwEB7joXam82KEVQI-A_7h3xqdZUMhGXRTAVLACLCFE3PNj0R6rliQ/s1600/Uca-tetragonon.jpg"><img alt="Tetragonal Fiddler Crab (Uca tetragonon)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhfkMfPv_YjkojPWJqeW_Ujnym-qOBtsKwwEwsnpiiN9W8hoXpz7HIIIO3dFGJsncgQ2XJtLEFCeoy2a1fRuwEB7joXam82KEVQI-A_7h3xqdZUMhGXRTAVLACLCFE3PNj0R6rliQ/s400/Uca-tetragonon.jpg" title="Tetragonal Fiddler Crab (Uca tetragonon)" width="400" /></a><br />
The <b>Tetragonal Fiddler Crab (<i>Uca tetragonon</i>)</b> is possibly the most marine of all the local fiddler crabs. It is usually found on soft substrates in sheltered areas near coral reefs. This pretty crab has a bright blue carapace with black patches. The big cheliped is relatively smooth and and stout. The maximum carapace width is about 3.5cm.<br />
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<b>References</b><br />
<ul style="text-align: left;">
<li>Crane, J. 1975. <i>Fiddler crabs of the world: Ocypodidae: Genus </i>Uca. Princeton, NJ: Princeton University Press. 400 pp.</li>
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>ETI BioInformatics. 2012. <i>Marine species identification portal</i>. Retrieved Jul 8, 2013, from http://species-identification.org.</li>
<li>Ng, P. K. L., L. K. Wang & K. K. P. Lim (eds.). 2008. <i>Private lives: An exposé of Singapore’s mangroves</i>. Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 240 pp.</li>
<li>Ng, P. K. L. & N. Sivasothi (eds.), 1999. <i>A guide to the mangroves of Singapore II: animal diversity</i>. Singapore Science Centre. 168p.</li>
<li>Ng, P. K. L., S. S. L. Lim, L. K. Wang & L. W. H. Tan. 2007. <i>Private lives: An exposé of Singapore's shores</i>. Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 212 pp.</li>
<li>Rosenberg, M. S. 2003. <i>Fiddler crabs</i>. Retrieved Jul 20, 2013, from http://www.fiddlercrab.info.</li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
</div>
Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com0tag:blogger.com,1999:blog-9797239.post-12807456800377931672013-07-26T16:48:00.000+08:002013-07-26T18:04:28.201+08:00Porter Crabs (Phylum Arthropoda: Family Dorippidae) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
Porter crabs (phylum Arthropoda, subphylum Crustacea, class Malacostraca, order Decapoda, superfamily Dorippoidea, family Dorippidae) are often not easy to spot on the seashore, as they usually camouflage themselves by carrying a leaf, broken shell, sea urchin, sea anemone or other small items (both living and non-living) on their back.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjqmx1ZOn4mLY6YRBEktB_rhPGz7b7ynLmgkFDNNWLWQ3kpHccHEw6jnFe-tT_Q7oZqhJmsiSA-2zM39UKKw8lx_Kwy6R7W9J55zMVtcy0ml9EhXgbXHzCFIhzpODeThqmRER36FA/s1600/Dorippidae.jpg"><img alt="Leaf Porter Crab (Neodorripe callida)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjqmx1ZOn4mLY6YRBEktB_rhPGz7b7ynLmgkFDNNWLWQ3kpHccHEw6jnFe-tT_Q7oZqhJmsiSA-2zM39UKKw8lx_Kwy6R7W9J55zMVtcy0ml9EhXgbXHzCFIhzpODeThqmRER36FA/s400/Dorippidae.jpg" title="Leaf Porter Crab (Neodorripe callida)" width="400" /></a><br />
Without the item they are carrying, porter crabs can be recognised by their last two pairs of legs, which are oriented upwards for carrying things instead of downwards for walking. The carapace is usually somewhat trapezoidal, with the front margin narrower than the rear margin. They are mostly scavengers.<br />
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Like other true crabs, porter crabs have a broad carapace, and a very short and flattened abdomen which is usually folded underneath the body. They also have five pairs of "legs" (including the clawed arms, or chelipeds), and hence they are placed in the order Decapoda ("deca" means "ten", while "poda" means "feet"). The gills are leaf-like - a distinctive characteristic of decapods from the suborder Pleocyemata. And as with other crustaceans from the class Malacostraca, their body comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head is fused to the thorax, forming a cephalothorax. They have a tough exoskeleton strengthened with calcium carbonate, and the carapace covers the gills but not the abdomen.<br />
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Porter crabs reproduce sexually, and have separate sexes. They mate face-to-face, usually with the male on top and the female below. The females can usually be distinguished from the males by having a broader abdomen. This is an adaptation to allow them to carry the eggs under their abdomen until they hatch.<br />
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I have only personally seen one species of porter crab in the wild in Singapore, though several species have been recorded by scientists.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj9EMGCFzmZUIaIs5Os3vX6gen4xCFXfd0F6ewyrijCu0Zk2wvlM0DnkJdCH9KdcTj7w2HAc0AHjHhWvwlMod6xY8sHLzM9IXIl7TuuCyKl7NFcuQb_tTK9Dd1_osfGhVs-Y6ONuQ/s1600/Neodorripe_callida_1.jpg"><img alt="Leaf Porter Crab (Neodorripe callida)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj9EMGCFzmZUIaIs5Os3vX6gen4xCFXfd0F6ewyrijCu0Zk2wvlM0DnkJdCH9KdcTj7w2HAc0AHjHhWvwlMod6xY8sHLzM9IXIl7TuuCyKl7NFcuQb_tTK9Dd1_osfGhVs-Y6ONuQ/s400/Neodorripe_callida_1.jpg" title="Leaf Porter Crab (Neodorripe callida)" width="400" /></a><br />
The <b>Leaf Porter Crab (<i>Neodorripe callida</i>)</b> does not only carry leaves, but various other items on their back for camouflage purposes. In the photo above, the crab was carrying a sand dollar.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhYkR2X6ESCv8M5iG_J_QJcDmGdyYeXf3F8e1Tq4-JTwGhYr5Gw3mBSnImv5R2lKhU9laseX9Z9Aw8nbyzI1Rm49vuBeVrMRCXdrm1FTcg_WgPLXUufmj5iGdJT-FTk0bGFsxm50Q/s1600/Neodorripe_callida.jpg"><img alt="Leaf Porter Crab (Neodorripe callida)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhYkR2X6ESCv8M5iG_J_QJcDmGdyYeXf3F8e1Tq4-JTwGhYr5Gw3mBSnImv5R2lKhU9laseX9Z9Aw8nbyzI1Rm49vuBeVrMRCXdrm1FTcg_WgPLXUufmj5iGdJT-FTk0bGFsxm50Q/s400/Neodorripe_callida.jpg" title="Leaf Porter Crab (Neodorripe callida)" width="400" /></a><br />
Sometimes, Leaf Porter Crabs can also be seen swimming upside-down near the water surface, with the leaf they are carrying facing downwards, appearing just like a floating debris when viewed from below!<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6-BvwTifQH2iBeb0XiuWV2cDmJle7vVMPL97fdtglkNkz-3oyrXlECFSPQbYCd4sdY91N8L1TRjsib6l7v3sw4RA7fJar3giIWNafFvBRy_afz1hCUHOLNSwuKCbtMffCU_-SNw/s1600/Neodorripe-callida.jpg"><img alt="Leaf Porter Crab (Neodorripe callida)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6-BvwTifQH2iBeb0XiuWV2cDmJle7vVMPL97fdtglkNkz-3oyrXlECFSPQbYCd4sdY91N8L1TRjsib6l7v3sw4RA7fJar3giIWNafFvBRy_afz1hCUHOLNSwuKCbtMffCU_-SNw/s400/Neodorripe-callida.jpg" title="Leaf Porter Crab (Neodorripe callida)" width="400" /></a><br />
This species can be distinguished from the other species recorded from Singapore by having a carapace that is distinctively longer than broad. The other species recorded so far from Singapore have broader than long carapaces.<br />
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<hr />
<br />
<b>References</b><br />
<ul style="text-align: left;">
<li>Carpenter, K. E. & V. H. Niem (eds), 1998-2001. <i>FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific</i>. Volumes 1 to 6. FAO, Rome. pp. 1-4218.</li>
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>Debelius, H. 1999. <i>Crustacea - Guide of the world</i>. IKAN, Frankfurt. 321pp.</li>
<li>ETI BioInformatics. 2012. <i>Marine species identification portal</i>. Retrieved Jul 8, 2013, from http://species-identification.org.</li>
<li>Ng, P. K. L., L. K. Wang & K. K. P. Lim (eds.). 2008. <i>Private lives: An exposé of Singapore’s mangroves</i>. Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 240 pp.</li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
</div>
Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com0tag:blogger.com,1999:blog-9797239.post-61220274876919123422013-07-26T16:43:00.003+08:002013-07-26T18:04:28.223+08:00Epialtid Spider Crabs (Phylum Arthropoda: Family Epialtidae) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
Epialtid spider crabs (phylum Arthropoda, subphylum Crustacea, class Malacostraca, order Decapoda, superfamily Majoidea, family Epialtidae) typically have a triangular, longer than broad, flattish carapace, and the entire exoskeleton is mostly covered in hooked hairs (which helps to cling on to encrusting organisms or collect sediment for camouflage). The rostrum (nose-like tip at the front) is relatively huge and beak-like, and may be simple or two-spined.<br />
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Epialtid spider crabs can usually be distinguished from other spider crabs (families <a href="http://tidechaser.blogspot.sg/2013/07/spider-crabs-majidae-singapore.html">Majidae</a> and <a href="http://tidechaser.blogspot.sg/2013/07/velcro-crabs-inachidae-singapore.html">Inachidae</a>) found on our shores by their very shot eyestalks and the lack of eyeholes (or orbits). However, this is not a very useful feature in the field as they are usually overgrown with algae or other encrusting organisms. The epialtid spider crabs that occur in Singapore waters are usually very small (not more than one or two cm long), and hence, the small size, relatively huge rostrum and elongate triangular shape are often more useful. They feed mainly on marine algae or other plant materials.<br />
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Like other true crabs, epialtid spider crabs have a broad carapace, and a very short and flattened abdomen which is usually folded underneath the body. They also have five pairs of "legs" (including the clawed arms, or chelipeds), and hence they are placed in the order Decapoda ("deca" means "ten", while "poda" means "feet"). The gills are leaf-like - a distinctive characteristic of decapods from the suborder Pleocyemata. And as with other crustaceans from the class Malacostraca, their body comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head is fused to the thorax, forming a cephalothorax. They have a tough exoskeleton strengthened with calcium carbonate, and the carapace covers the gills but not the abdomen.<br />
<br />
Epialtid spider crabs reproduce sexually, and have separate sexes. They mate face-to-face, usually with the male on top and the female below. The females can usually be distinguished from the males by having a broader abdomen. This is an adaptation to allow them to carry the eggs under their abdomen until they hatch.<br />
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I have only personally seen one species of epialtid spider crab in the wild in Singapore.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgWh8EdQulasYDhXnjTIY3DgK7xvJbgPW5eQ3Q8CXqBOy12q70MwybT5BonACvnQvnpqE_NZ0x7HlPmjQ_ORp-FeJ5Sl8C7tXjsdR2Oj80SAP_e4S6eUqOeqVV20hrZyg_UoyBD6A/s1600/Menaethius_monoceros.jpg"><img alt="One-horned Spider Crab (Menaethius monoceros)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgWh8EdQulasYDhXnjTIY3DgK7xvJbgPW5eQ3Q8CXqBOy12q70MwybT5BonACvnQvnpqE_NZ0x7HlPmjQ_ORp-FeJ5Sl8C7tXjsdR2Oj80SAP_e4S6eUqOeqVV20hrZyg_UoyBD6A/s400/Menaethius_monoceros.jpg" title="One-horned Spider Crab (Menaethius monoceros)" width="400" /></a><br />
The <b>One-horned Spider Crab (<i>Menaethius monoceros</i>)</b> is usually found living among seaweeds. Its cryptic coloration and the algae and other debris attached to its body often allow them to camouflage well with the surrounding. It has a triangular carapace, with three teeth on each side margin. The chelipeds of the males are longer than any of its legs, and the beak-like structure at the front is long and slender. The carapace gets to about 1cm wide.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEikCI03TSSHLkcmESQB77OglU2JkQwe9I36YXl-tVP866b4qOmZIetxaFuJgKhfJEFctKZCCXfpEolSCcmku8OtrYqMV9Zhba4ROr6Nv3t9-i1Bpy-DAr7xT-bWCRjGtHDbsGyoyQ/s1600/Menaethius-monoceros.jpg"><img alt="One-horned Spider Crab (Menaethius monoceros)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEikCI03TSSHLkcmESQB77OglU2JkQwe9I36YXl-tVP866b4qOmZIetxaFuJgKhfJEFctKZCCXfpEolSCcmku8OtrYqMV9Zhba4ROr6Nv3t9-i1Bpy-DAr7xT-bWCRjGtHDbsGyoyQ/s400/Menaethius-monoceros.jpg" title="One-horned Spider Crab (Menaethius monoceros)" width="400" /></a><br />
Sometimes, it may be overgrown with algae, and it is hard to confirm the identify in the field.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgFzPixTgJgnoJSEX5gblJ4PYDUHB7WuIfxtyETKPQqvlXqyFw5q17GoCB0bn2LrAckMiXFl5H5BzvtxHh7abUzPWwYvVKznlfMU7110BTW0TVmyEzK7MvnuepnAbW1-bMHmFNKjg/s1600/unknown22.jpg"><img alt="Spider Crab" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgFzPixTgJgnoJSEX5gblJ4PYDUHB7WuIfxtyETKPQqvlXqyFw5q17GoCB0bn2LrAckMiXFl5H5BzvtxHh7abUzPWwYvVKznlfMU7110BTW0TVmyEzK7MvnuepnAbW1-bMHmFNKjg/s400/unknown22.jpg" title="Spider Crab" width="400" /></a><br />
I have also seen smaller spider crabs, some of them with very long extensions protruding from the head. I am not sure if they are of the same species though.<br />
<br />
<hr />
<br />
<b>References</b><br />
<ul style="text-align: left;">
<li>Carpenter, K. E. & V. H. Niem (eds), 1998-2001. <i>FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific</i>. Volumes 1 to 6. FAO, Rome. pp. 1-4218.</li>
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>Debelius, H. 1999. <i>Crustacea - Guide of the world</i>. IKAN, Frankfurt. 321pp.</li>
<li>ETI BioInformatics. 2012. <i>Marine species identification portal</i>. Retrieved Jul 8, 2013, from http://species-identification.org.</li>
<li>Ng, P. K. L., S. S. L. Lim, L. K. Wang & L. W. H. Tan. 2007. <i>Private lives: An exposé of Singapore's shores</i>. Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 212 pp.</li>
<li>Ng, P. K .L., R. T. Corlett & H.T.W. Tan (eds.). 2011. <i>Singapore biodiversity: An encyclopedia of the natural environment and sustainable development</i>. Singapore: Editions Didier Millet. 552 pp.</li>
<li>Vasconcelos M. A., T. C. Mendes, W. L. S. Fortes& R. C. Pereira. 2009. Feeding and decoration preferences of the Epialtidae Crab Acanthonix scutiforms. <i>Brazilian Journal of Oceanography</i>, 57: 137-143.</li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
</div>
Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com0tag:blogger.com,1999:blog-9797239.post-71437352727057381842013-07-26T16:42:00.001+08:002013-07-26T18:04:28.228+08:00Inachid Spider Crabs (Phylum Arthropoda: Family Inachidae) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
Inachid spider crabs (phylum Arthropoda, subphylum Crustacea, class Malacostraca, order Decapoda, superfamily Majoidea, family Inachidae) often have velcro-like hooked hairs on their exoskeleton, which helps to hold on to sponges, asidians and small bits of debris for camouflage purposes. The hooked hair is present in other spider crabs (superfamily Majoidea) though.<br />
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Inachid spider crabs can be distinguished from other spider crabs (families <a href="http://tidechaser.blogspot.sg/2013/07/spider-crabs-majidae-singapore.html">Majidae</a> and <a href="http://tidechaser.blogspot.sg/2013/07/epialtidae-spider-crabs-singapore.html">Epialtidae</a>) by their visibly long eyestalks and the lack of obvious orbits (i.e. eyeholes). The carapace is triangular or teardrop-shaped, with a short rostrum that may come with a single spine. Studies suggest that they either scavenge or feed on small invertebrates. Unlike most other crabs, these crabs can move forward-backwards instead of just sideways.<br />
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Like other true crabs, inachid spider crabs have a broad carapace, and a very short and flattened abdomen which is usually folded underneath the body. They also have five pairs of "legs" (including the clawed arms, or chelipeds), and hence they are placed in the order Decapoda ("deca" means "ten", while "poda" means "feet"). The gills are leaf-like - a distinctive characteristic of decapods from the suborder Pleocyemata. And as with other crustaceans from the class Malacostraca, their body comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head is fused to the thorax, forming a cephalothorax. They have a tough exoskeleton strengthened with calcium carbonate, and the carapace covers the gills but not the abdomen.<br />
<br />
Inachid spider crabs reproduce sexually, and have separate sexes. They mate face-to-face, usually with the male on top and the female below. The females can usually be distinguished from the males by having a broader abdomen. This is an adaptation to allow them to carry the eggs under their abdomen until they hatch.<br />
<br />
I have only personally seen one species of inachid spider crab in the wild in Singapore.<br />
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<hr />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYYw2jX07kfujYMUhZ_QDeeCysGyqyncCaKzlEhzvgbJmIiofSD1OGMXShsTLDyzP19CuJMxLR-HjReNBBWj3IsA-tXe7y6dnk0i1znyP1uZjPTU7KVZoOsC686paEGEf83Tuvow/s1600/Camposcia-retusa.jpg"><img alt="Decorator Crab (Camposcia retusa)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYYw2jX07kfujYMUhZ_QDeeCysGyqyncCaKzlEhzvgbJmIiofSD1OGMXShsTLDyzP19CuJMxLR-HjReNBBWj3IsA-tXe7y6dnk0i1znyP1uZjPTU7KVZoOsC686paEGEf83Tuvow/s400/Camposcia-retusa.jpg" title="Decorator Crab (Camposcia retusa)" width="400" /></a><br />
The <b>Decorator Crab (<i>Camposcia retusa</i>)</b> is so-named for their habit of attaching various items on their body, ranging from debris such as shell fragments and loose rocks, to sessile organisms, such as sponges, ascidians and algae. It is sometimes also called Velcro Crab for the hook-like hairs on its exoskeleton, which helps to hold on to the items attached to it. The photo above features one which was covered mostly with ascidians and sponges. This species can grow to about 5cm wide (carapace only).<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkTm8QJuX6zGtjz4m639Gl7Ae3TQow6DdyX4NyV1zmUX97HfCUt4dUIhqjwx7-jkrXgzW83sGRM5zLTP3vbB8QOWC3_X-w_VKii4POhXZVBH6mYzizQY-hsfRFU2wq_pja_5-nRA/s1600/Camposcia-retusa_1.jpg"><img alt="Decorator Crab (Camposcia retusa)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkTm8QJuX6zGtjz4m639Gl7Ae3TQow6DdyX4NyV1zmUX97HfCUt4dUIhqjwx7-jkrXgzW83sGRM5zLTP3vbB8QOWC3_X-w_VKii4POhXZVBH6mYzizQY-hsfRFU2wq_pja_5-nRA/s400/Camposcia-retusa_1.jpg" title="Decorator Crab (Camposcia retusa)" width="400" /></a><br />
The Decorator Crab above covered itself with some red coraline algae in addition to some asidians.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhVIVUSJnpxFq90kCnTr3ahAkZp2AZlZCY-sa_k5S7cFcjCcEEF6JCtu0VL3s2ZXODOyupIZk5GUUDw-b5-JRTGln3QiQ-WW4TVD2bbh1u-mjIneYRWh5K45B4zFGrzDBiu-HJcxA/s1600/Camposcia_retusa.jpg"><img alt="Decorator Crab (Camposcia retusa)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhVIVUSJnpxFq90kCnTr3ahAkZp2AZlZCY-sa_k5S7cFcjCcEEF6JCtu0VL3s2ZXODOyupIZk5GUUDw-b5-JRTGln3QiQ-WW4TVD2bbh1u-mjIneYRWh5K45B4zFGrzDBiu-HJcxA/s400/Camposcia_retusa.jpg" title="Decorator Crab (Camposcia retusa)" width="400" /></a><br />
When sessile organisms are scarce, the Decorator Crab may attach shell fragments and small stones to itself as well.<br />
<br />
<hr />
<br />
<b>References</b><br />
<ul style="text-align: left;">
<li>Carpenter, K. E. & V. H. Niem (eds), 1998-2001. <i>FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific</i>. Volumes 1 to 6. FAO, Rome. pp. 1-4218.</li>
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>Debelius, H. 1999. <i>Crustacea - Guide of the world</i>. IKAN, Frankfurt. 321pp.</li>
<li>ETI BioInformatics. 2012. <i>Marine species identification portal</i>. Retrieved Jul 8, 2013, from http://species-identification.org.</li>
<li>Ng, P. K. L., S. S. L. Lim, L. K. Wang & L. W. H. Tan. 2007. <i>Private lives: An exposé of Singapore's shores</i>. Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 212 pp.</li>
<li>Ng, P. K .L., R. T. Corlett & H.T.W. Tan (eds.). 2011. <i>Singapore biodiversity: An encyclopedia of the natural environment and sustainable development</i>. Singapore: Editions Didier Millet. 552 pp.</li>
<li>Vasconcelos M. A., T. C. Mendes, W. L. S. Fortes& R. C. Pereira. 2009. Feeding and decoration preferences of the Epialtidae Crab Acanthonix scutiforms. <i>Brazilian Journal of Oceanography</i>, 57: 137-143.</li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
</div>
Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com0tag:blogger.com,1999:blog-9797239.post-40999998904580539652013-07-26T16:39:00.001+08:002013-07-26T18:04:28.210+08:00True Spider Crabs (Phylum Arthropoda: Family Majidae) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
True spider crabs (phylum Arthropoda, subphylum Crustacea, class Malacostraca, order Decapoda, superfamily Majoidea, family Majidae) can be distinguished from other spider crabs (families <a href="http://tidechaser.blogspot.sg/2013/07/velcro-crabs-inachidae-singapore.html">Inachidae</a> and <a href="http://tidechaser.blogspot.sg/2013/07/epialtidae-spider-crabs-singapore.html">Epialtidae</a>) by having eyes with nearly complete or complete orbits (i.e. eyeholes). A pair of sharp spines can usually be found at the front near the eye, and sometimes the spines may bear smaller spinelets.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkkIe_W08jq9PXwHLO6SzCZoZcr0Hb28ANz70ufevg24oa1pB0H7vAc3lEypwJxSrSl_im24Oq0lF5gr9eJ7lS0ERkiJXikhM4EQiyEjdU8A2gex4gZn56LI-rFCTou3i9mUGOeg/s1600/Micippaphilyra.jpg"><img alt="Philyra Spider Crab (Micippa philyra)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkkIe_W08jq9PXwHLO6SzCZoZcr0Hb28ANz70ufevg24oa1pB0H7vAc3lEypwJxSrSl_im24Oq0lF5gr9eJ7lS0ERkiJXikhM4EQiyEjdU8A2gex4gZn56LI-rFCTou3i9mUGOeg/s400/Micippaphilyra.jpg" title="Philyra Spider Crab (Micippa philyra)" width="400" /></a><br />
The carapace is usually triangular or pear-shaped, often with spines by the sides. The entire exoskeleton is usually covered in hooked hairs which trap sediment and other sessile organisms such as ascidians and sponges, allowing it to blend into the surrounding.<br />
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Unlike most other crabs, true spider crabs can move forward-backwards instead of just sideways. They are usually scavengers, though some are known to actively hunt small invertebrates as well. Some of the smaller species can be mistaken for <a href="http://tidechaser.blogspot.sg/2013/07/sponge-crabs-dromiidae-singapore.html">sponge crabs (family Dromiidae)</a>. Spider crabs, however, attached the sessile organisms to the hooked hairs on their backs, unlike the sponge crabs which carry them using their rear legs.<br />
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Like other crabs, true spider crabs have a broad carapace, and a very short and flattened abdomen which is usually folded underneath the body. They also have five pairs of "legs" (including the clawed arms, or chelipeds), and hence they are placed in the order Decapoda ("deca" means "ten", while "poda" means "feet"). The gills are leaf-like - a distinctive characteristic of decapods from the suborder Pleocyemata. And as with other crustaceans from the class Malacostraca, their body comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head is fused to the thorax, forming a cephalothorax. They have a tough exoskeleton strengthened with calcium carbonate, and the carapace covers the gills but not the abdomen.<br />
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True spider crabs reproduce sexually, and have separate sexes. They mate face-to-face, usually with the male on top and the female below. The females can usually be distinguished from the males by having a broader abdomen. This is an adaptation to allow them to carry the eggs under their abdomen until they hatch.<br />
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Here are the true spiders crabs that I have photographed in Singapore.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMF3qgK2PIoOS0GX5nbdK87dKMMFyrTp3CJnHwkqYGSw0iulqeoTX7O5RGwL5-62HXbeJDjn5MgFlPe_Ln5aeAx9_BiU2nxuFUZopC-3dYXY-xRvVBGYyiaQmoqPHvFwSFg7CM6w/s1600/Micippa-philyra.jpg"><img alt="Philyra Spider Crab (Micippa philyra)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMF3qgK2PIoOS0GX5nbdK87dKMMFyrTp3CJnHwkqYGSw0iulqeoTX7O5RGwL5-62HXbeJDjn5MgFlPe_Ln5aeAx9_BiU2nxuFUZopC-3dYXY-xRvVBGYyiaQmoqPHvFwSFg7CM6w/s400/Micippa-philyra.jpg" title="Philyra Spider Crab (Micippa philyra)" width="400" /></a><br />
The <b>Philyra Spider Crab (<i>Micippa philyra</i>)</b> is named after a Greek mythological character, the ocean nymph, Philyra. This little spider crab is usually not more than 3cm wide (carapace only), and is often hard to spot due to the ascidians and sponges that it has attached to its body, allowing it to blend nicely into the surrounding.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg6HbPLxZ9wV1nMyinE1e1XbB6MVLdSGZG-IPECQV9SNZRYNtkpH2Qd0PxwfuijGFhXBV3YVT4b5SnsOkDcqhDZ2A1B0VA3wTwiHluJLDk8-2HoJx6ce-ZLtktyQIzHpKST07FP-w/s1600/Micippa_philyra.jpg"><img alt="Philyra Spider Crab (Micippa philyra)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg6HbPLxZ9wV1nMyinE1e1XbB6MVLdSGZG-IPECQV9SNZRYNtkpH2Qd0PxwfuijGFhXBV3YVT4b5SnsOkDcqhDZ2A1B0VA3wTwiHluJLDk8-2HoJx6ce-ZLtktyQIzHpKST07FP-w/s400/Micippa_philyra.jpg" title="Philyra Spider Crab (Micippa philyra)" width="400" /></a><br />
When the crab is turned over, the hook-like legs are revealed. This crab is usually found on coral rubble flats or in the coral reef.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgpFevlyvfwoAPsCbQU43nXch4IyfYj0i3sEFJA_HQVIXtlL0mW3t3m4WYWi-v5fgAbZdqZ2sLtQDp_5eHlFspIfL-C8IHBnuR4hAb5vcCfMGbwf1xP5UJNQJd8rWQz5N9DmBNIlQ/s1600/Schizophrys_aspera.jpg"><img alt="Sea Toad (Schizophrys aspera)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgpFevlyvfwoAPsCbQU43nXch4IyfYj0i3sEFJA_HQVIXtlL0mW3t3m4WYWi-v5fgAbZdqZ2sLtQDp_5eHlFspIfL-C8IHBnuR4hAb5vcCfMGbwf1xP5UJNQJd8rWQz5N9DmBNIlQ/s400/Schizophrys_aspera.jpg" title="Sea Toad (Schizophrys aspera)" width="400" /></a><br />
The <b>Sea Toad (<i>Schizophrys aspera</i>)</b> is another master of camouflage that is often overgrown with ascidians. The carapace is somewhat pear-shaped, and the margins are lined with shape spines. It has a pair of horn-like structures extending from the front of the carapace. Two species of <i>Schizophrys </i>are recorded from Singapore, and they can be distinguished by looking at the pair of horns. The above species can be recognised by having only one spinelet branching out near the middle of the horn, while the other species, <i>Schizophrys dama</i>, has horns with two spinelets. The maximum carapace width for both species is about 6cm, and they are usually found on rocky shores, coral rubble flats and coral reefs. These spider crabs are sometimes collected for consumption by locals.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEivRt_Prr2Bt153fY_-XxaLCKHvIcLnLC6Nxwc0aGakdkCplPGCK9cBcdCx88F4LoAt1-n6A9Q2kL2lgzywIU7mekKEgKKSfVb4nUyRtaiy0Y5tZ1dTc7BybY2dq3ZRi9Z1QUaytQ/s1600/Schizophrys.jpg"><img alt="Schizophrys" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEivRt_Prr2Bt153fY_-XxaLCKHvIcLnLC6Nxwc0aGakdkCplPGCK9cBcdCx88F4LoAt1-n6A9Q2kL2lgzywIU7mekKEgKKSfVb4nUyRtaiy0Y5tZ1dTc7BybY2dq3ZRi9Z1QUaytQ/s400/Schizophrys.jpg" title="Schizophrys" width="400" /></a><br />
The above photo features an unidentified <i>Schizophrys </i>species. Note that the size of the chelipeds varies even within members of the same species.<br />
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<b>References</b><br />
<ul style="text-align: left;">
<li>Carpenter, K. E. & V. H. Niem (eds), 1998-2001. <i>FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific</i>. Volumes 1 to 6. FAO, Rome. pp. 1-4218.</li>
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>Debelius, H. 1999. <i>Crustacea - Guide of the world</i>. IKAN, Frankfurt. 321pp.</li>
<li>ETI BioInformatics. 2012. <i>Marine species identification portal</i>. Retrieved Jul 8, 2013, from http://species-identification.org.</li>
<li>Ng, P. K. L., S. S. L. Lim, L. K. Wang & L. W. H. Tan. 2007. <i>Private lives: An exposé of Singapore's shores</i>. Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 212 pp.</li>
<li>Ng, P. K .L., R. T. Corlett & H.T.W. Tan (eds.). 2011. <i>Singapore biodiversity: An encyclopedia of the natural environment and sustainable development</i>. Singapore: Editions Didier Millet. 552 pp.</li>
<li>Tan, L. W. H. & P. K. L. Ng. 1988. <i>A Guide to Seashore Life</i>. Singapore Science Centre. Singapore. 160 pp.</li>
<li>Vasconcelos M. A., T. C. Mendes, W. L. S. Fortes& R. C. Pereira. 2009. Feeding and decoration preferences of the Epialtidae Crab Acanthonix scutiforms. <i>Brazilian Journal of Oceanography</i>, 57: 137-143.</li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
</div>
Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com0tag:blogger.com,1999:blog-9797239.post-87430465058510245802013-07-26T16:37:00.001+08:002013-07-26T18:04:28.235+08:00Sponge Crabs (Phylum Arthropoda: Family Dromiidae) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
Sponge crabs (phylum Arthropoda, subphylum Crustacea, class Malacostraca, order Decapoda, superfamily Dromioidea, family Dromiidae) are so-named for their habit of carrying a piece of living sponge or colonial ascidian for camouflage purposes. They are mostly scavengers, and hence help to clear the sea floor of dead animals.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEidcrKPmT37OwG4TSrhZLbcRi665eY4NG0jK4gKSB3xIHfYw73Y5BpyK9oFoZDXJ1CjS8YfvmSVMBjrpGTSS2iyNdnabcrB4ARyCR3SQFUVkqeNNv-FzUmrzlA40XU4ynwr6VkK1g/s1600/Lauridromia_indica.jpg"><img alt="Cannonball Sponge Crab (Lauridromia indica)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEidcrKPmT37OwG4TSrhZLbcRi665eY4NG0jK4gKSB3xIHfYw73Y5BpyK9oFoZDXJ1CjS8YfvmSVMBjrpGTSS2iyNdnabcrB4ARyCR3SQFUVkqeNNv-FzUmrzlA40XU4ynwr6VkK1g/s400/Lauridromia_indica.jpg" title="Cannonball Sponge Crab (Lauridromia indica)" width="400" /></a><br />
Some sponge crabs may be mistaken for spider crabs (family Majidae), but their method of carrying the ascidians and sponges are different. Sponge crabs carry the ascidians or sponges with their last two pairs of legs. These legs are inserted obliquely on the circular to hexagonal carapace, directed upwards. Hence, sponge crabs only use two pair of legs for walking. Spider crabs, on the other hand, stick the ascidians or sponges to the hooked hairs on their exoskeletons, and use all four pairs of legs for walking.<br />
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Like other crabs, sponge crabs have a broad carapace, and a very short and flattened abdomen which is usually folded underneath the body. They also have five pairs of "legs" (including the clawed arms, or chelipeds), and hence they are placed in the order Decapoda ("deca" means "ten", while "poda" means "feet"). The gills are leaf-like - a distinctive characteristic of decapods from the suborder Pleocyemata. And as with other crustaceans from the class Malacostraca, their body comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head is fused to the thorax, forming a cephalothorax. They have a tough exoskeleton strengthened with calcium carbonate, and the carapace covers the gills but not the abdomen.<br />
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Sponge crabs reproduce sexually, and have separate sexes. They mate face-to-face, usually with the male on top and the female below. The females can usually be distinguished from the males by having a broader abdomen. This is an adaptation to allow them to carry the eggs under their abdomen until they hatch.<br />
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Here are the sponge crabs that I have photographed in Singapore.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgVJPs6tk1NVo2CldQhvLZeYxZlAO9T7DJXlT6X_GmiiGE8uPr5idy1JaZaRPsPhPji_zEyP3Vi-RMevddhbnu3v0zyBXlulrim4I-pHKT1Vj40izzT0ex2wO91-n5xhHyJig0ytg/s1600/Lauridromia-indica.jpg"><img alt="Cannonball Sponge Crab (Lauridromia indica)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgVJPs6tk1NVo2CldQhvLZeYxZlAO9T7DJXlT6X_GmiiGE8uPr5idy1JaZaRPsPhPji_zEyP3Vi-RMevddhbnu3v0zyBXlulrim4I-pHKT1Vj40izzT0ex2wO91-n5xhHyJig0ytg/s400/Lauridromia-indica.jpg" title="Cannonball Sponge Crab (Lauridromia indica)" width="400" /></a><br />
The <b>Cannonball Sponge Crab (<i>Lauridromia indica</i>)</b> is so-named for its round body. It is sometimes called the Pink-fingered Sponge Crab for its pink fingers, but despite that, it is not the only sponge crab with pink fingers. It is, however, the only one recorded in local shallow waters so far that has pink fingers and can grow to about 8cm wide. There is a possibility that other similar species may occur in local waters though, but just not discovered yet. The above photo features one with a brown colonial ascidian.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiIZ6ZVVYT4vY4x3XKNd8_YrvJPvNjRm4K_B7_KvXu9llCVQnq9Gjq3aCQkjWUvt_NNBY_8Ss_5qEpZuIOG42QxnfYW3fhak-oOQiJI9_VotU1vhW2VEr4dIGIdzE-ZA8D3DLHQSA/s1600/Lauridromia-indica.jpg"><img alt="Cannonball Sponge Crab (Lauridromia indica)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiIZ6ZVVYT4vY4x3XKNd8_YrvJPvNjRm4K_B7_KvXu9llCVQnq9Gjq3aCQkjWUvt_NNBY_8Ss_5qEpZuIOG42QxnfYW3fhak-oOQiJI9_VotU1vhW2VEr4dIGIdzE-ZA8D3DLHQSA/s400/Lauridromia-indica.jpg" title="Cannonball Sponge Crab (Lauridromia indica)" width="400" /></a><br />
Occasionally, some Cannonball Sponge Crabs without holding a sponge or ascidian can be seen. Its carapace is usually wider than long, and on each side of the carapace, there are six teeth of about the same size. The rostrum (beak-like structure between the eyes on the carapace) is made up of three pointed spines. Newly moulted specimens may have a pinkish body in addition to the pink fingers. This very common species is sometimes collected for consumption, but is generally not popular due to the poor quality of the meat.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9D8SpOqTW6IU1l_G7xQOJ84PKxGdlWjtyCz9lWXOByh4C7LriapBhnZqwzrS1vQo5M4nALHMhkawJ1teLHD4sIq7hZq2Dd3QRIWhFhrzbAO85sNv0zfmyHZ7SHfu-EtXzm7TgOg/s1600/Dromidiopsis-edwardsi.jpg"><img alt="Edward's Sponge Crab (Dromidiopsis edwardsi)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9D8SpOqTW6IU1l_G7xQOJ84PKxGdlWjtyCz9lWXOByh4C7LriapBhnZqwzrS1vQo5M4nALHMhkawJ1teLHD4sIq7hZq2Dd3QRIWhFhrzbAO85sNv0zfmyHZ7SHfu-EtXzm7TgOg/s400/Dromidiopsis-edwardsi.jpg" title="Edward's Sponge Crab (Dromidiopsis edwardsi)" width="400" /></a><br />
The above is possibly the <b>Edward's Sponge Crab (<i>Dromidiopsis edwardsi</i>)</b>, which also has a rostrum made up of three pointed spines but the pincers bear whitish fingers. Its carapace is approximately as long as wide, and the last pair of legs are relatively short. The above photo features one carrying a red colonial ascidian, and its carapace is about 1.5-2cm wide.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEidgDyM-pozxBmOnI5JNhNIYGHZnbxFppKWP9ilTZoz1UduI9K9yzoJsRWKAD6uc7uEij-LTnCjW488i28pV_PMEcZIwWCYrnOcQelrp9g2NcCCqL0ARRikEqAVR0CcXEDf49CmQQ/s1600/Cryptodromia-tuberculata.jpg"><img alt="Tuberculate Sponge Crab (Cryptodromia tuberculata)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEidgDyM-pozxBmOnI5JNhNIYGHZnbxFppKWP9ilTZoz1UduI9K9yzoJsRWKAD6uc7uEij-LTnCjW488i28pV_PMEcZIwWCYrnOcQelrp9g2NcCCqL0ARRikEqAVR0CcXEDf49CmQQ/s400/Cryptodromia-tuberculata.jpg" title="Tuberculate Sponge Crab (Cryptodromia tuberculata)" width="400" /></a><br />
The <b>Tuberculate Sponge Crab (<i>Cryptodromia tuberculata</i>)</b>, or Bumpy Sponge Crab as I call it, has numerous tubercles (i.e. pointed bumps) on its chelipeds. The carapace is wider than long, and the front margin between the eyes has three very blunt and inconspicuous teeth, looking more like a wavy structure. The centre teeth is usually more prominent that the two by the sides. Sometimes, the carapace may be marked with dark patches. This small sponge crab gets to about 1cm wide (carapace only). The above photo features one carrying a yellowish sponge.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgu9yxGIQoyXfbHShuhgL91tiqrFgeE8ksRkM1pGUDCLNcLdzxa-7KwecQ31GbiOe2Mjqvu4dcsOR1BK-xRtqGIZHpkB718tjas3QcaDMwUCE9yvBIVhudEPXRHG9YXUcAfcmM54w/s1600/Lewindromia-unidentata.jpg">
<img alt="Hairy Sponge Crab (Lewindromia unidentata)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgu9yxGIQoyXfbHShuhgL91tiqrFgeE8ksRkM1pGUDCLNcLdzxa-7KwecQ31GbiOe2Mjqvu4dcsOR1BK-xRtqGIZHpkB718tjas3QcaDMwUCE9yvBIVhudEPXRHG9YXUcAfcmM54w/s400/Lewindromia-unidentata.jpg" title="Hairy Sponge Crab (Lewindromia unidentata)" width="400" /></a><br />
The <b>Hairy Sponge Crab (<i>Lewindromia unidentata</i>)</b> is generally covered in fine hair. The carapace is approximately as long as wide, and the sides have no spines. The rostrum has three points, with the one in the middle being smaller, but usually this is hard to see in the field as the crab is covered in hair. The pincer fingers are strongly curved downwards, and whitish in colour. The maximum carapace width of this small crab is about 1cm.<br />
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<br />
<b>References</b><br />
<ul style="text-align: left;">
<li>Carpenter, K. E. & V. H. Niem (eds), 1998-2001. <i>FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific</i>. Volumes 1 to 6. FAO, Rome. pp. 1-4218.</li>
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>Debelius, H. 1999. <i>Crustacea - Guide of the world</i>. IKAN, Frankfurt. 321pp.</li>
<li>ETI BioInformatics. 2012. <i>Marine species identification portal</i>. Retrieved Jul 8, 2013, from http://species-identification.org.</li>
<li>McLay, CL (2001) The Dromiidae of French Polynesia and a new collection of crabs (Crustacea, Decapoda, Brachyura) from the Marquesas Islands. <i>Zoosystema </i>23(1): 77-100. </li>
<li>McLay, C. L. & P. K. L. Ng. 2005. On a collection of Dromiidae and Dynomenidae from the Philippines, with description of a new species of Hirsutodynomene McLay, 1999 (Crustacea: Decapoda: Brachyura). <i>Zootaxa</i>. 1029, 1–30. </li>
<li>National Science Council of Taiwan. 2004. <i>BiotaTaiwanica</i>. Retrieved Jul 10, 2013, http://biota.taibif.org.tw </li>
<li>Ng, P. K. L., S. S. L. Lim, L. K. Wang & L. W. H. Tan. 2007. <i>Private lives: An exposé of Singapore's shores</i>. Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 212 pp.</li>
<li>Ng, P. K .L., R. T. Corlett & H.T.W. Tan (eds.). 2011. <i>Singapore biodiversity: An encyclopedia of the natural environment and sustainable development</i>. Singapore: Editions Didier Millet. 552 pp.</li>
<li>Tan, L. W. H. & P. K. L. Ng. 1988. <i>A Guide to Seashore Life</i>. Singapore Science Centre. Singapore. 160 pp.</li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
</div>
Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com0tag:blogger.com,1999:blog-9797239.post-78208566406952784092013-07-26T16:35:00.000+08:002013-11-27T17:31:07.867+08:00Pebble Crabs (Phylum Arthropoda: Family Leucosiidae) of Singapore<div dir="ltr" style="text-align: left;" trbidi="on">
Pebble crabs (phylum Arthropoda, subphylum Crustacea, class Malacostraca, order Decapoda, superfamily Leucosioidea, family Leucosiidae) usually have circular, oval or pentagonal carapaces. Many species have a convex carapace, and appear much like round pebbles, and hence the common name.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7AeHI4ItKg3hcaihPKAaUhs14xmb4nuQLWemsPRWZO1a30__g7Ve1y_se142n1tZObxymFl1RnH-SG1RuFYPgl_1mEDhnrPAtCAheLLi6SnhjjKsgRBbma_SHve48WpOBpKC5jA/s1600/Leucosiidae.jpg"><img alt="Pebble Crab (Family Leucosiidae)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7AeHI4ItKg3hcaihPKAaUhs14xmb4nuQLWemsPRWZO1a30__g7Ve1y_se142n1tZObxymFl1RnH-SG1RuFYPgl_1mEDhnrPAtCAheLLi6SnhjjKsgRBbma_SHve48WpOBpKC5jA/s400/Leucosiidae.jpg" title="Pebble Crab (Family Leucosiidae)" width="400" /></a><br />
The eyes and antennae are very tiny and hardly noticeable, and the chelipeds are symmetrical. Most pebble crabs are adapted for burrowing, and are found in soft substrates like sand or mud. Many species feed on tiny invertebrates by probing the top layer of the sediment and capturing the ones disturbed.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFilB-yuSv5nHAifIjx9IZfKa4gEnB3H86Rro74rg6mJyKmMZys4yHsoRqEqxlzTvSl9f_T4caJTbUfhwR5I7pq2_rqdncIg2TWHadURqOoAxalo43AJEiQrYbqFj7BXrccXY9ng/s1600/Leucosiidae.jpg"><img alt="Pebble Crab (Family Leucosiidae)" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFilB-yuSv5nHAifIjx9IZfKa4gEnB3H86Rro74rg6mJyKmMZys4yHsoRqEqxlzTvSl9f_T4caJTbUfhwR5I7pq2_rqdncIg2TWHadURqOoAxalo43AJEiQrYbqFj7BXrccXY9ng/s400/Leucosiidae.jpg" title="Pebble Crab (Family Leucosiidae)" width="400" /></a><br />
Like other crabs, pebble crabs have a broad carapace, and a very short and flattened abdomen which is usually folded underneath the body. They also have five pairs of "legs" (including the clawed arms, or chelipeds), and hence they are placed in the order Decapoda ("deca" means "ten", while "poda" means "feet"). The gills are leaf-like - a distinctive characteristic of decapods from the suborder Pleocyemata. And as with other crustaceans from the class Malacostraca, their body comprises three main parts - a head with five segments, a thorax with eight segments, and an abdomen with six segments. The head is fused to the thorax, forming a cephalothorax. They have a tough exoskeleton strengthened with calcium carbonate, and the carapace covers the gills but not the abdomen.<br />
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Pebble crabs reproduce sexually, and have separate sexes. They mate face-to-face, usually with the male on top and the female below. The females can usually be distinguished from the males by having a broader abdomen. This is an adaptation to allow them to carry the eggs under their abdomen until they hatch.<br />
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Unfortunately, I am still unable to identify the species of pebble crabs that I have seen so far.<br />
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<b>References</b><br />
<ul style="text-align: left;">
<li>De Grave, S., N. D. Pentcheff , S. T. Ahyong, T.-Y. Chan, K. A. Crandall, P. C. Dworschak, D. L. Felder, R. M. Feldmann, C. H. J. M. Fransen, L. Y. D. Goulding, R. Lemaitre, M. E. Y. Low, J. W. Martin, P. K. L. Ng, C. E. Schweitzer, S. H. Tan, D. Tshudy & R. Wetzer. 2009. A classification of living and fossil genera of decapod crustaceans. <i>The Raffles Bulletin of Zoology</i>, supplement 21, pp. 1-109.</li>
<li>Debelius, H. 1999. <i>Crustacea - Guide of the world</i>. IKAN, Frankfurt. 321pp.</li>
<li>Ng, P. K. L., S. S. L. Lim, L. K. Wang & L. W. H. Tan. 2007. <i>Private lives: An exposé of Singapore's shores</i>. Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore. 212 pp.</li>
<li>Ng, P. K .L., R. T. Corlett & H.T.W. Tan (eds.). 2011. <i>Singapore biodiversity: An encyclopedia of the natural environment and sustainable development</i>. Singapore: Editions Didier Millet. 552 pp.</li>
<li><i>World Register of Marine Species</i>. 2012. Retrieved Jun 10, 2013, from http://www.marinespecies.org.</li>
</ul>
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Ron Yeohttp://www.blogger.com/profile/14985280422009642787noreply@blogger.com0