Peanut
worms
Phylum Sipuncula
updated
Oct 2016
if you
learn only 3 things about them ...
They
are smooth unsegmented worms.
Common but rarely seen as they usually remain underground.
The
introvert is one of the interesting parts of this worm. |
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Where
seen? These pink smooth fat worms are sometimes seen on
some of our shores. They are more commonly encountered in mangroves
and on soft ground (silty or muddy). But also in sandy areas near
seagrasses.
What are peanut worms? Peanut
worms are unsegmented and belong to Phylum Sipuncula. There are about
300 known species of peanut worms. |
Cyrene Reef, Apr 07 |
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Pasir Ris, May 09 |
Features: 5-10cm long. Peanut
worms are burrowing worm-like creatures that are sometimes seen above
the ground on all our shores. When contracted, their ridged skins
looks like the texture of peanut shells. Most are only a few millimeters
long. Some burrow in mud, while others hide in crevices or abandoned
snail shells and even in tubeworm tubes. 'Siphunculus' means 'little
tube'. What is unique to peanut worms is their introvert, a long tube
on their front end.
This is attached to the rest of the body, called the trunk. Like the
finger of a glove, the introvert can be turned completely inside the
trunk or extend out of the trunk. The mouth is at the end of the introvert,
surrounded with tentacles.
The tentacles are covered with cilia (tiny beating hairs) and mucous.
Food particles are gathered with the tentacles and then either the
entire introvert is withdrawn into the trunk and the food particles
eaten, or cilia on the tentacles transfer the particles along tracts
into the mouth. Using their introvert, peanut worms can collect food
while their soft bodies remain safely hidden. Some also use their
introvert to burrow. One species even uses its introvert to swim! |
Pulau Senang, Jun 10
Photo shared by Loh Kok Sheng on his
flickr.
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What do they eat? Most peanut
worms eat detritus, most of them mopping it up from the surface. Others
eat their way through the sand as they burrow, and process the edible
bits in it. They have a J-shaped digestive tract with the anus in
the middle of the body so that wastes are brought back up near the
entrance of the burrow. One kind of peanut worm can actually pierce
annelid worms and suck out their juices!
Peanut worm babies: Peanut worms
have separate genders, releasing eggs and sperm simultaneously into
the water for external fertilisation. Some have a free-swimming larval
stage that can travel long distances. In others, the eggs develop
directly into little peanut worms.
Human uses: Peanut worms were
once so plentiful in Singapore that they were collected and fed to
ducks.
Status and threats: Like other
creatures of the intertidal zone, they are affected by human activities
such as reclamation and pollution. Trampling by careless visitors
can also have an impact on local populations. |
Peanut
worms on Singapore shores |
Chek Jawa, Apr 02 |
Chek Jawa, Nov 03 |
Changi, Jul 08 |
Changi, Jan 15
Photo shared by Marcus Ng on flickr. |
|
Pulau Sekudu, Jul 09
Photo shared by Marcus Ng on his
blog. |
Changi CP7, Jan 21
Photo shared by Vincent Choo on facebook. |
Berlayar Creek, Apr 12 |
Pulau Hantu, Apr 21
Photo shared by Vincent Choo on facbook. |
Pulau Semakau East, Jul 15
Photo shared by Heng Pei Yan on facbook. |
Pulau Semakau West, Jan 21
Photo shared by Jianlin Liu on facbook. |
Pulau Senang, Jun 10
Photo shared by Loh Kok Sheng on his
flickr. |
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Peanut worms seen
above ground in Tanah Merah after the oil spill in May 10
Tanah Merah, May 10 |
Tanah Merah, Jun 10 |
Tanah Merah, Jun 10 |
Tanah Merah, Jul 10 |
Tanah Merah, Jul 10 |
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Phylum
Sipuncula recorded for Singapore
from
Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity
in Singapore
*from WORMS
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*Family
Phascolosomatidae |
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Phascolosoma arcuatum=**Phascolosoma (Phascolosoma) arcuatum
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Dendrostomum
signifer=*Themiste (Lagenopsis) lageniformis Themistidae (Family)
Phascolosoma arcuatum=**Phascolosoma (Phascolosoma) arcuatum
Phascolosomatidae (Family)
Siphonosoma cumanense
Sipunculus nudus
Sipunculus robustus |
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Dendrostomum
signifer=*Themiste (Lagenopsis) lageniformis |
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Links
- Peanut
worm (Phylum Sipunculida) Tan, Leo W. H. & Ng, Peter K. L.,
1988. A Guide to Seashore Life. The Singapore Science Centre,
Singapore. 160 pp.
- Peanut
Worm (Sipunculids) Ng, Peter K. L. & N. Sivasothi, 1999. A
Guide to the Mangroves of Singapore II (Animal Diversity).
Singapore Science Centre. 168 pp.
- Peanut
worms on Life
on Australian Seashores by Keith Davey on the Marine Education
Society of Australia website: an introduction to worms including
sipunculids with explanations of the major parts of their bodies
and their lifestyles, and fact sheet on a peanut worm found in
Australia.
References
- P.-W. Hsueh & K. S. Tan. 29 June 2016. New records of peanut worms (Sipuncula) from Singapore. The Raffles Bulletin of Zoology 2016 Supplement No. 34 (Part I of II). Pp. 235-240.
- Ng, P. K.
L. & Y. C. Wee, 1994. The
Singapore Red Data Book: Threatened Plants and Animals of Singapore.
The Nature Society (Singapore), Singapore. 343 pp.
- Wee Y.C.
and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore.
National Council on the Environment. 163pp.
- Edward E.
Ruppert, Richard S. Fox, Robert D. Barnes. 2004.Invertebrate
Zoology
Brooks/Cole of Thomson Learning Inc., 7th Edition. pp. 963
- Pechenik,
Jan A., 2005. Biology
of the Invertebrates.
5th edition. McGraw-Hill Book Co., Singapore. 578 pp.
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