Rafting crab
Plagusia sp.
Family Plagusiidae
updated
Dec 2019
Where
seen? This bumpy crab that resembles the Sally-light-foot
crab (Grapsus albolineatus) is sometimes seen on rocky shores in the North and South. Previously placed in Family
Grapsidae.
Features: Body width 5-6cm. Body
oval (not so circular), convex (not flat), covered with small bumps. Pincers short slender. Walking legs
long fringed with short hairs, tipped with pointy claws. With these
legs, the crab clings tightly so it doesn't get washed away in the
waves, and can scramble quickly among slippery rocks. Mottled body
and legs. Colours seen include shades of brown, blue, purple, orange.
Sometimes mistaken for the Sally-light-foot
crab (Grapsus albolineatus) which has a more circular flatter
smoother body. |
Changi, Jul 12 |
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Changi, Aug 12 |
Depression between the eyes. |
| Rafting crabs on Singapore shores |
| Other sightings on Singapore shores |
Changi-Loyang, Jul 20
Photo shared by Loh Kok Sheng on facebook.
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Chek Jawa, Jul 13
Photo shared by Loh Kok Sheng on flickr.
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East Coast Park, Jul 14
Photo shared by Loh Kok Sheng on flickr.
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East Coast Park, May 21
Photo shared by Loh Kok Sheng on facebook.
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Kusu Island, Aug 17
Photo shared by Marcus Ng on facebook.
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Kusu Island, May 16
Photo shared by Jonathan Tan on facebook.
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Raffles Lighthouse, Aug 08
Photo shared by Loh Kok Sheng on flickr.
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Raffles Lighthouse, Nov 16
Photo shared by Loh Kok Sheng on facebook.
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Family
Plagusiidae recorded for Singapore
from
Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity
in Singapore
+from The Biodiversity of Singapore, Lee Kong Chian Natural History Museum.
**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.
^from WORMS
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**Family
Plagusiidae (previously Grapsidae) |
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+Plagusia immaculata
^Plagusia
squamosa=Plagusia tuberculata
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Acknowledgements
Grateful thanks to Ondřej Radosta from ID Please (Marine Creatures) facebook page for helping me to understand this crab.
Links
References
- Christoph D. Schubart and Peter K. L. Ng, "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)" on The Raffles Bulletin of Zoology 2000 48(2): 327-336.
- Jones Diana
S. and Gary J. Morgan, 2002. A Field Guide to Crustaceans of
Australian Waters. Reed New Holland. 224 pp.
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