Tuesday, January 01, 2008

Semakau Coral ID Assignment

This is a long over-due entry. Had thought of just posting the photos in some online album, but realised that it's probably easier for Jani to glance through on a blog entry. This is actually an assignment for our coral class, conducted by Jani, our local coral expert.

So here goes:

Family Acroporidae

Genus Acropora

Commonly called staghorn coral, this coral needs clear water to do well, and thus is not as common in Singapore compared to places like Tioman or Redang. Due to their fast growth rate (up to an inch per month), they often dominate a reef by out-growing and overshadowing other corals as they reach out for more sunlight in a table or branching growth form.

Genus Montipora

This coral is very common in Singapore, and is yet another fast grower. When the polyps are out, this coral can look rather similar to another coral, Porites. One way to tell the difference is to look at the corallite, which lacks a columella in Montipora.

Family Agariciidae

Genus Pavona

The above is a wide shot of the leaf coral to show its growth form. The common name came from the leafy-like growth form. Personally I thought it can look rather similar to another coral, Psammocora, especially from afar.

Looking close, however, the intricate patterns show.

Family Euphyllidae (or Caryophylliidae)

Genus Euphyllia

Didn't managed to get a shot of the anchor coral which has anchor-shaped tip as the water turned too murky, but managed to get one of its close relative, another Euphyllia sp. This one has white-tipped tentacles, which reminds me of the sunflower mushroom coral (Heliofungia actiniformis).

Family Dendrophylliidae

Genus Turbinaria

Have seen huge colonies of Turbinaria at Sentosa, but the ones in Semakau are all rather small. Somehow this is one coral that appears to be able to do well in murky waters like those at Sentosa. It is also called the plate coral sometimes, and the reason is pretty obvious from the photo above.

Here's another species.

Updated: Had thought that the one above resembles Astreopora the most, but I thought I can see the columella that Astreopora supposedly lacks. Was thinking the next closest will be Turbinaria. Indeed, as per commented by Jani, this is Turbinaria.

Family Faviidae

Genus Oulastrea

Have been finding small colonies of this coral at many places, including Changi! This is perhaps one of the easiest favids to identify, due to its zebra-coloured corallite walls which give it its common name, zebra coral.

Genus Platygyra or Goniastrea

The above is probably a Platygyra sp., which its corallite walls develops looking like a maze looking from the top, thus earning it the common maze coral. It can be differentiated from another similar looking coral, Oulophyllia , with its more ragged wall with exerting septa, while Oulophyllia corallites have v-shaped valleys and thinner septa. Updated: Jani commented that from the photo can't really confirm that it is Platygyra, but very likely could be Goniastrea.

Have no idea the genus of the following corals from Faviidae though.

Family Fungiidae

Genus Fungia

Mushroom corals are quite common on Semakau, and sometimes you can find many of them in all sizes around the same spot. Sometimes, you can even find little ones looking like mushroom growing on a stalk! And that's also why it's called mushroom coral, and don't you think the septa stretching away from the mouth look like gills of a real mushroom? By the way, this whole coral is one single animal, unlike most other corals which live in a colony.

Genus Ctenactis or Fungia

Here's another mushroom coral, which has a slightly more elongated shape. It is also a single living animal.

Genus Heliofungia (Heliofungia actiniformis)

The sunflower mushroom coral (Heliofungia actiniformis) is yet another common coral on Semakau. The genus is also monospecific, i.e. only one species. Unlike most other mushroom corals, this one has long tentacles with a white tip. It is also a single living animal.

Genus Herpolitha (Herpolitha limax)

Yet another mushroom coral, sometimes called the boomerang mushroom coral (Herpolitha limax), due to the boomberang shape it may attain when it grows bigger. This genus is monospecific, and the coral is a actually a colony of animals. Each colony has several polyps in an axial groove, and usually by the sides there are smaller polyps with their mouths interrupting the septa.

Genus Polyphyllia (Polyphyllia talpina)

So far only one species from this genus has been found in Singapore, Polyphyllia talpina. Commonly called the slipper mushroom coral as it is usually long and narrow, this is a colony of animals too. The little tentacles have white tips.

Family Merulinidae

Genus Merulina

Not clearly shown in the above photo due to the murky water, this coral has railway-track-like septa growth, thus giving it its common name, railway track coral.

Family Mussidae

Genus Symphyllia

Also called the brain coral due to its appearance, one way of differentiating this genus from others in the family is that a prominent groove runs along the length of the corallite wall for some species, as seen in the above photo. Also, adjacent polyp walls are completely fused.

Genus Lobophyllia

This is probably a Lobophyllia sp. since it doesn't have the characteristics mentioned above under Symphyllia. Also called the lobed brain coral.

Family Oculinidae

Genus Galaxea

This coral is given the common name of galaxy coral as the polyps look like stars with their little white-tipped tentacles.

Family Pectiniidae

Genus Pectinia

Sometimes also called the carnation coral, this coral gets its common name from the petal-like growth form.

Some species are also called spiny cup corals, and it's easy to tell why by looking at the above photo.

Family Pocilloporidae

Genus Pocillopora

This coral is also commonly called the cauliflower coral or bush coral due to its branching growth form, especially when it's under water and you can see the tentacles giving it an outer coating.

Family Poritidae

Genus Porites

We can usually find massive colonies of Porites at many of our southern islands. This coral has really tiny polyps, and can sometimes be confused with Montipora, as highlighted above.

For example, take a look at the branching Porites above, and it looks like a Montipora from afar, especially when the corallites look like black holes. However, if you look at it really close up and perhaps you'll need to take a macro shot to be sure, you'll noticed that it has a tiny speck in the middle - the columella. Pardon that the reflection from the water making it less obvious though, but when we look really close up on the spot it was more obvious.

Genus Goniopora

This is a very pretty coral that we sometimes call it anemone coral, because it has such long and pretty tentacles, and resembles a sea anemone.

Here's another one with a different colour. And by the way, count the tentacles on each polyp, and you'll noticed that there are 24 of them!

Family Siderastreidae

Genus Psammocora

As per mentioned above under Pavona, I sometimes find these two corals sometimes like rather similar, especially in murky water and from afar.

However, if you take a closer look, you will realised that the corallites of a Psammocora form lovely petaloid patterns.

A coral that is hard but is not a hard coral...

Last but not least, I thought I'll just add this - a coral that is hard but is not a hard coral!

Sounds confusing? Well, this is actually a blue coral (Heliopora sp.), which is more closely related to the soft corals!

Unlike hard corals which have tentacles in multiples of 6, and are thus in the subclass Hexacorallia, this coral has 8 tentacles, and is in the subclass Octocorallia, like the soft corals! It is called blue coral because it has blue skeleton.


Mountain & Sea said...

Hi Ron, yours make for easier reading and ID as compared to the books that I have been pouring over to ID my own pictures, and still getting them wrong.

Yours definitely look better and easier to understand.


tHE tiDE cHAsER said...

Thanks for the compliment! :)

Fried Tempeh said...

Hey Ron,

Great blog! And great photos! With great descriptive captions! It's great that you take colony shots...and close up shots as well...which helps in the ID a lot. Your camera zoom is really good so it's like looking under a magnifying glass! Excellent stuff!

Genus Astreopora - yes, I think this photo is of Turbinaria. I think your photo shows it more clearly than the lighting under the setting sun!

Genus Platygyra - Actually you would need a more close up shot of the corallites for this coral. As the most similar looking coral in Singapore would be Goniastrea. The difference is the Goniastrea has paliformed lobes (teeth-like formation on the septa), whereas in Platygyra this structure is absent. So can't positively ID this one based on the photo taken.

Genus Ctenactis - I think this looks more like an oval-ish Fungia than Ctenactis. Ctenactis is usually more longish than this. USUALLY...can't be sure though...have to look at the corallum wall whether perforated or not.

EXCELLENT JOB! You've got a really good ID blog going on!! We should definitely do something like this after consolidating everyone's photos! Though so far, your group is leading with 22 IDs so can prolly just add onto your blog and make it the ID site haha...


tHE tiDE cHAsER said...

Thanks Jani for your comments!