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Spotted
box crab
Calappa philargius
Family Calappidae
updated
Dec 08
Where
seen? This large boxy crab with four big spots on its flat
pincers is sometimes seen on the sandy shores of Changi near seagrass
areas. It is more active at night and are rarely seen by daytime visitors
as it is then usually buried in the sediments. Once, several pairs
were seen half buried near one another.
Features:
Body width 8-10cm. It does look rather box-like with a
semi-circular body and wing-like extensions on the sides and back
that cover part of the walking legs. The Spotted box crab is identified
by a total of six spots: two dark spots on each pincer and a dark
ring around each eye. It holds its pincers in front of its body to
form a boxy shape. So it is sometimes also called the Shame-face crab
as it appears to be covering its face in shame.
What does it eat? The pincers
of box crabs are specialised for cracking open snail shells. The snail
is gripped in the left pincer which has pointed claws. With the right
pincer, which is stronger, the crab cuts pieces of the shell from
the shell opening. Once the gap is big enough, the crab can enjoy
its snail meal.
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Changi, May
06 
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| Status
and threats: Our box crabs are listed as 'Vulnerable'
on the Red List of threatened animals of Singapore.
Like other creatures of the intertidal zone, they are affected
by human activities such as reclamation and pollution.
Trampling
by careless visitors also have an impact on local populations. |
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Changi, May 06
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Spotted
box crabs seen on Singapore shores
Changi, Apr
05
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Changi, Apr
05 
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Changi, May
06 
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Changi, May
06
A pair buried next to one another.
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Family
Calappidae recorded for Singapore
from
Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity
in Singapore
in
red are those listed among the threatened animals of Singapore from
Davison, G.W. H. and P. K. L. Ng and Ho Hua Chew, 2008. The Singapore
Red Data Book: Threatened plants and animals of Singapore.
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Calappa
lophos (VU: Vulnerable)
Calappa hepatica (VU: Vulnerable)
Calappa philargius (Spotted
box crab)
(VU: Vulnerable) |
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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. (Online
PDF on the Raffles Bulletin of Zoology website)
- Lim, S.,
P. Ng, L. Tan, & W. Y. Chin, 1994. Rhythm of the Sea: The Life
and Times of Labrador Beach. Division of Biology, School of
Science, Nanyang Technological University & Department of Zoology,
the National University of Singapore. 160 pp.
- Davison,
G.W. H. and P. K. L. Ng and Ho Hua Chew, 2008. The Singapore
Red Data Book: Threatened plants and animals of Singapore.
Nature Society (Singapore). 285 pp.
- 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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