Myriapods (phylum Arthropoda, subphylum Myriapoda) are typically elongate arthropods which possess numerous pairs of legs ("myriapoda" means "10,000 legs" in ancient Greek), a trunk with many segments, and a head with one pair each of mandibles and antennae at the front end.
Like other arthropods, they have jointed legs ("arthropoda" means "jointed legs" in ancient Greek), a bilaterally symmetrical body, and a tough exoskeleton (or external skeleton) composed largely of a tough material called chitin. As they grow, they need to moult, i.e. discard the old skeleton and grow a new one. The cuticle (i.e. outer covering) of myriapods is not waterproof, and hence they are largely terrestrial. Most species are also nocturnal to avoid water loss, and are most readily found in damp habitats such as the leaf litter or underground. They can breathe by taking in air through openings in the cuticle.
Myriapods are generally harmless to human, except for some venomous species. The bites may be painful, but are rarely fatal unless the victim is allergic to the venom.
Here are some examples of myriapods that can be seen in Singapore:
A) MILLIPEDES (CLASS DIPLOPODA)
Millipedes are easily recognised by their long segmented body with two pairs of legs on most segments, except for the first few and last segments. The name means "a thousand legs", but while there are species in the world with more than 700 legs, the ones seen in Singapore seldom have more than 100. Most species feed on decaying organic matter or fungi, and hence they are commonly seen in the leaf litter or on fallen trees. They are not venomous, and protect themselves either by secreting toxic or distasteful chemicals, or roll up to protect their softer underparts, exposing only the tougher upperparts. To breed, the males usually twist their bodies around the females to transfer the sperm, and the females will lay the eggs inside a nest in the soil. The newly hatched millipedes usually have much fewer legs than the adults, and gain more legs and body segments as they moult.
Order Spirobolida
Spirobolid millipedes generally have cylindrical bodies, and are usually found in leaf litter or under logs. When disturbed, they tend to curl up and secrete toxic chemicals to deter predators. They can be distinguished from other millipedes by having only one (instead of two) pair of legs on the fifth segment. The reproductive organs of the males are within a pouch.
The Rusty Millipede (Trigoniulus corallinus) is one of the commonest native millipedes that can be encountered in both urban and rural areas in Singapore. It has a reddish, cylindrical body, and often rolls up into a coil when disturbed. The above photo features a mating pair. This species grows to about 5cm long.
Order Spirostreptida
Spirostreptid millipedes are usually large cylindrical millipedes with only one pair of reproductive organs. They are mostly found in the tropics, and many species have strong legs to climb up trees. When disturbed, they can secrete toxic or distasteful chemicals through pores on their sides to deter predators.
This dark red Giant Millipede (Thyropygus sp.) is seen in the forest climbing up a tree. It is about 20cm long.
This Giant Millipede (Thyropygus sp.) that has black and orange body segments is also about 20cm long.
Order Polydesmida
Polydesmid millipedes typically have between 18 to 22 body rings, with 20 rings being the commonest. They are eyeless, and most are able to secrete toxic cyanide to defend themselves against predators. Many species have their body segments which resemble flatten plates, and hence they are often called flat-back millipedes. These species are also commonly called tractor millipedes as the segments resemble the tyre tracks of tractors. Not all polydesmids have this appearance though, and some may come with roundish segments.
The Black-and-Yellow Millipede (Anoplodesmus saussurii) is another commonly encountered species, but is unfortunately an introduced one, believed to be native to the Indian subcontinent. It probably came with imported plants, and is now very commonly seen in parks and gardens. This species often occurs in high densities, sometimes up to a few hundred individuals in the same area. It grows to about 3cm long, and can be recognised by the shiny black upperparts and yellow rounded structures by the sides. Many millipedes have the same coloration, but are usually less shiny and the structures by the sides are not as rounded.
The above unidentified polydesmid millipede has a similar yellow-and-black coloration, but the structures by the sides are pointed instead of being rounded.
The above unidentified species with very flattish segments was seen in the forest.
This arboreal polydesmid millipede is possibly Opisthodolichopus scandens. It has round reddish segments with a dark line on the back. The ones I have seen are about 5cm long.
This is likely to be a Opisthodolichopus sp., but I am not sure if it is the same species as the previous one as the colours are different.
Order Sphaerotheriida
Sphaerotheriid millipedes are commonly called giant pill millipedes as they are generally larger than other pill millipedes of the same super order, Oniscomorpha. Apart from the larger size, they also can be differentiated from other pill millipedes by having 13 body segments, inclusive of the head.
Pill millipedes got their common name from the fact that they will roll into a ball (or pill) when disturbed, hence only exposing their tougher backs and hide the softer underparts.
The above unidentified pill millipede is about 2cm long.
Order Polyxenida
Members of this order are generally small millipedes of a few millimetres long with their bodies densely covered with tiny bristles-like structures. Unlike most other millipedes, they do not secrete chemicals for defense purposes, but instead brush their bristles against their predators. The barbed bristles will penetrate into the body of the predator, causing great discomfort or even death. Polyxenid millipedes are usually found under rocks, in leaf litter or on logs. Unfortunately, I do not have usable photos of these millipedes yet.
Order Siphonophorida
Members of this order Siphonophorida are characterised by having either a somewhat conical front end with the mouthparts elongated into a long, bird-like beak with reduced mandibles. They hold the "world record" for having the most number of legs, with one American species having as many as 375 pairs. Their reproductive organs are very simple and leg-like, being derived from the ninth and tenth legs. Little is known about their diet, though scientists deduced from the shapes of their mouthparts that they probably feed on plant materials. Unfortunately, I do not have photos of these millipedes yet.
B) CENTIPEDES (CLASS CHILOPODA)
Centipedes are myriapods with an elongate and flattened body made up of at least 16 segments. Each segment has one pair of legs. Interestingly, they always have an odd number of pairs of legs, with the last pair longer than the rest, and the first pair modified into venomous fangs (or forcipules). They are mostly nocturnal, and use their venomous fangs to hunt smaller animals, which can include both vertebrates and invertebrates. While the venom is generally not fatal to human, been bitten by the bigger species can be very painful. The victim may also experience headaches and nausea for a few days, and the bitten area may swell up. Death cases are extremely rare, unless the victim is allergic to the venom. To breed, the males usually drop the sperm on the ground that the females pick up. The eggs may be laid singly or brooded in batches underground.
Order Scolopendromorpha
Scolopendromorph centipedes are usually large and robust with large fangs that can give very painful bites. They often come in bright colours, sometimes with stripes, and possess either 21 or 23 pairs of legs. They can move relatively fast, and the females tend to be more aggressive, often killing and eating their mates. Many are eyeless, though some may have simple eyes that can detect light and darkness.
The above is a Scolopendra sp. which can grow to over 15cm long. These large centipedes are known to feed on smaller animals such as insects, lizards and even mice.
This black centipede is probably an Otostigmus sp. It was found under a rock, and the female was noted to provide parental care for the eggs, coiling around its eggs.
Order Scutigeromorpha
Members of this order are often called house centipedes or cave centipedes, as they are often seen indoor or in caves. They have a pair of long antennae, 15 pairs of very long legs, and are the only group of centipedes with large compound eyes, and hence making them very fast hunters. Many species can give painful bites.
This cave centipede, Thereuopoda longicornis, is usually seen in the forest in Singapore. This is the only species of scutigeromorph centipede that has been recorded from here so far.
Order Geophilomorpha
Members of the order are also recorded from Singapore, but unfortunately I still lack usable photos. They are usually very long and slender, with at least 35 body segments. The legs are short, as these eyeless centipedes are adapted for burrowing. They have weak mandibles, and typically feed on small, soft-bodied invertebrates.
C) SYMPHYLANS (CLASS SYMPHYLA)
The symphylans are small, whitish myriapods with a soft body made up of 15 segments, including a head with a pair of long antennae and three pairs of mouthparts, and a trunk made up of 14 segments. A pair of tail-like structures (or spinnerets) extends from the last segment. They have no eyes, and are often found in the soil or in the leaf litter, feeding on plant materials. Some species are perceived as garden pest, as they feed on living plant matter, such as the roots. To breed, the males deposit sperm packages that are picked up by the females.
The above photo features an unidentified symphylan found among the leaf litter.
References
Like other arthropods, they have jointed legs ("arthropoda" means "jointed legs" in ancient Greek), a bilaterally symmetrical body, and a tough exoskeleton (or external skeleton) composed largely of a tough material called chitin. As they grow, they need to moult, i.e. discard the old skeleton and grow a new one. The cuticle (i.e. outer covering) of myriapods is not waterproof, and hence they are largely terrestrial. Most species are also nocturnal to avoid water loss, and are most readily found in damp habitats such as the leaf litter or underground. They can breathe by taking in air through openings in the cuticle.
Myriapods are generally harmless to human, except for some venomous species. The bites may be painful, but are rarely fatal unless the victim is allergic to the venom.
Here are some examples of myriapods that can be seen in Singapore:
A) MILLIPEDES (CLASS DIPLOPODA)
Millipedes are easily recognised by their long segmented body with two pairs of legs on most segments, except for the first few and last segments. The name means "a thousand legs", but while there are species in the world with more than 700 legs, the ones seen in Singapore seldom have more than 100. Most species feed on decaying organic matter or fungi, and hence they are commonly seen in the leaf litter or on fallen trees. They are not venomous, and protect themselves either by secreting toxic or distasteful chemicals, or roll up to protect their softer underparts, exposing only the tougher upperparts. To breed, the males usually twist their bodies around the females to transfer the sperm, and the females will lay the eggs inside a nest in the soil. The newly hatched millipedes usually have much fewer legs than the adults, and gain more legs and body segments as they moult.
Order Spirobolida
Spirobolid millipedes generally have cylindrical bodies, and are usually found in leaf litter or under logs. When disturbed, they tend to curl up and secrete toxic chemicals to deter predators. They can be distinguished from other millipedes by having only one (instead of two) pair of legs on the fifth segment. The reproductive organs of the males are within a pouch.
The Rusty Millipede (Trigoniulus corallinus) is one of the commonest native millipedes that can be encountered in both urban and rural areas in Singapore. It has a reddish, cylindrical body, and often rolls up into a coil when disturbed. The above photo features a mating pair. This species grows to about 5cm long.
Order Spirostreptida
Spirostreptid millipedes are usually large cylindrical millipedes with only one pair of reproductive organs. They are mostly found in the tropics, and many species have strong legs to climb up trees. When disturbed, they can secrete toxic or distasteful chemicals through pores on their sides to deter predators.
This dark red Giant Millipede (Thyropygus sp.) is seen in the forest climbing up a tree. It is about 20cm long.
This Giant Millipede (Thyropygus sp.) that has black and orange body segments is also about 20cm long.
Order Polydesmida
Polydesmid millipedes typically have between 18 to 22 body rings, with 20 rings being the commonest. They are eyeless, and most are able to secrete toxic cyanide to defend themselves against predators. Many species have their body segments which resemble flatten plates, and hence they are often called flat-back millipedes. These species are also commonly called tractor millipedes as the segments resemble the tyre tracks of tractors. Not all polydesmids have this appearance though, and some may come with roundish segments.
The Black-and-Yellow Millipede (Anoplodesmus saussurii) is another commonly encountered species, but is unfortunately an introduced one, believed to be native to the Indian subcontinent. It probably came with imported plants, and is now very commonly seen in parks and gardens. This species often occurs in high densities, sometimes up to a few hundred individuals in the same area. It grows to about 3cm long, and can be recognised by the shiny black upperparts and yellow rounded structures by the sides. Many millipedes have the same coloration, but are usually less shiny and the structures by the sides are not as rounded.
The above unidentified polydesmid millipede has a similar yellow-and-black coloration, but the structures by the sides are pointed instead of being rounded.
The above unidentified species with very flattish segments was seen in the forest.
This arboreal polydesmid millipede is possibly Opisthodolichopus scandens. It has round reddish segments with a dark line on the back. The ones I have seen are about 5cm long.
This is likely to be a Opisthodolichopus sp., but I am not sure if it is the same species as the previous one as the colours are different.
Order Sphaerotheriida
Sphaerotheriid millipedes are commonly called giant pill millipedes as they are generally larger than other pill millipedes of the same super order, Oniscomorpha. Apart from the larger size, they also can be differentiated from other pill millipedes by having 13 body segments, inclusive of the head.
Pill millipedes got their common name from the fact that they will roll into a ball (or pill) when disturbed, hence only exposing their tougher backs and hide the softer underparts.
The above unidentified pill millipede is about 2cm long.
Order Polyxenida
Members of this order are generally small millipedes of a few millimetres long with their bodies densely covered with tiny bristles-like structures. Unlike most other millipedes, they do not secrete chemicals for defense purposes, but instead brush their bristles against their predators. The barbed bristles will penetrate into the body of the predator, causing great discomfort or even death. Polyxenid millipedes are usually found under rocks, in leaf litter or on logs. Unfortunately, I do not have usable photos of these millipedes yet.
Order Siphonophorida
Members of this order Siphonophorida are characterised by having either a somewhat conical front end with the mouthparts elongated into a long, bird-like beak with reduced mandibles. They hold the "world record" for having the most number of legs, with one American species having as many as 375 pairs. Their reproductive organs are very simple and leg-like, being derived from the ninth and tenth legs. Little is known about their diet, though scientists deduced from the shapes of their mouthparts that they probably feed on plant materials. Unfortunately, I do not have photos of these millipedes yet.
B) CENTIPEDES (CLASS CHILOPODA)
Centipedes are myriapods with an elongate and flattened body made up of at least 16 segments. Each segment has one pair of legs. Interestingly, they always have an odd number of pairs of legs, with the last pair longer than the rest, and the first pair modified into venomous fangs (or forcipules). They are mostly nocturnal, and use their venomous fangs to hunt smaller animals, which can include both vertebrates and invertebrates. While the venom is generally not fatal to human, been bitten by the bigger species can be very painful. The victim may also experience headaches and nausea for a few days, and the bitten area may swell up. Death cases are extremely rare, unless the victim is allergic to the venom. To breed, the males usually drop the sperm on the ground that the females pick up. The eggs may be laid singly or brooded in batches underground.
Order Scolopendromorpha
Scolopendromorph centipedes are usually large and robust with large fangs that can give very painful bites. They often come in bright colours, sometimes with stripes, and possess either 21 or 23 pairs of legs. They can move relatively fast, and the females tend to be more aggressive, often killing and eating their mates. Many are eyeless, though some may have simple eyes that can detect light and darkness.
The above is a Scolopendra sp. which can grow to over 15cm long. These large centipedes are known to feed on smaller animals such as insects, lizards and even mice.
This black centipede is probably an Otostigmus sp. It was found under a rock, and the female was noted to provide parental care for the eggs, coiling around its eggs.
Order Scutigeromorpha
Members of this order are often called house centipedes or cave centipedes, as they are often seen indoor or in caves. They have a pair of long antennae, 15 pairs of very long legs, and are the only group of centipedes with large compound eyes, and hence making them very fast hunters. Many species can give painful bites.
This cave centipede, Thereuopoda longicornis, is usually seen in the forest in Singapore. This is the only species of scutigeromorph centipede that has been recorded from here so far.
Order Geophilomorpha
Members of the order are also recorded from Singapore, but unfortunately I still lack usable photos. They are usually very long and slender, with at least 35 body segments. The legs are short, as these eyeless centipedes are adapted for burrowing. They have weak mandibles, and typically feed on small, soft-bodied invertebrates.
C) SYMPHYLANS (CLASS SYMPHYLA)
The symphylans are small, whitish myriapods with a soft body made up of 15 segments, including a head with a pair of long antennae and three pairs of mouthparts, and a trunk made up of 14 segments. A pair of tail-like structures (or spinnerets) extends from the last segment. They have no eyes, and are often found in the soil or in the leaf litter, feeding on plant materials. Some species are perceived as garden pest, as they feed on living plant matter, such as the roots. To breed, the males deposit sperm packages that are picked up by the females.
The above photo features an unidentified symphylan found among the leaf litter.
References
- Bartlett, T. & J. VanDyk. 2003. BugGuide. Retrieved May 24, 2013, http://bugguide.net.
- Burnie, D. 2001. Animal. London: Dorling Kindersley. 624 pp.
- Decker, P. & T. Tertilt. 2012. First records of two introduced millipedes Anoplodesmus saussurii and Chondromorpha xanthotricha (Diplopoda: Polydesmida: Paradoxosomatidae) in Singapore. Nature in Singapore, 5: 141–149.
- Marek, P., W. Shear & J. Bond. 2012. A redescription of the leggiest animal, the millipede Illacme plenipes, with notes on its natural history and biogeography (Diplopoda, Siphonophorida, Siphonorhinidae). ZooKeys 241 (241): 77–112.
- McGavin, G. 2000. Dorling Kindersley Handbooks: Insects, spiders and other terrestrial arthropods. London: Dorling Kindersley. 255 pp
- Ng, P. K .L., R.T. Corlett & H.T.W. Tan (eds.). 2011. Singapore Biodiversity: An Encyclopedia of the Natural Environment and Sustainable Development. Singapore: Editions Didier Millet. 552 pp.
- Read, H. J. & H. Enghoff. 2009. The order Siphonophorida - A taxonomist’s nightmare? Lessons from a Brazilian collection. Soil Organisms 81: 543-556.
