Semaphore
crab
Ilyoplax sp.
Family Dotillidae
updated
Dec 2019
Where
seen? This tiny but active crab is sometimes seen in our
mangroves. The common name comes from its habit of vigorously waving
its pincers up and down. This is reminiscent of the Semaphore flag-waving
system used by sailors in the past to send messages over long distances.
In the crab, this behaviour probably serves to declare territory and
to attract mates.
Features: Body width 0.5cm. Body
somewhat round, eyestalks short. Pincers equal sized and rather bulbous.
The White semaphore crab (Ilyoplax delsmani) changes its colour to
white to communicate with other semaphore crabs. When they are resting,
they turn a dull colour to blend in with the surrounding mud or sand. |
Lim Chu Kang, Aug 05 |
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Lim Chu Kang, Jan 04 |
| Semaphore
crabs on Singapore shores |
| Other sightings on Singapore shores |
Sungei Buloh, Nov 11
Photo shared by Loh Kok Sheng on flickr. |
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Links
References
- Ng, Peter
K. L. and Daniele Guinot and Peter J. F. Davie, 2008. Systema
Brachyurorum: Part 1. An annotated checklist of extant Brachyuran
crabs of the world. The Raffles Bulletin of Zoology. Supplement
No. 17, 31 Jan 2008. 286 pp.
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