seen? These tiny crabs are only found in living branching
hard corals such as Acropora
corals (Acropora sp.) and Cauliflower
corals (Pocillopora sp.). They are well hidden and quick,
and thus hard to spot and photograph.
Features: Body width about 1cm.
The body is flat and usually pentagonal (hard to see this on living
crabs which are usually well hidden). The pincers are large (relative
to the body), with pointed pincers. The legs are short with pointed
Usually a pair of male and female are found in one coral colony. The
females are generally larger than the males and the males have claws
that are proportionally larger.
These coral crabs feed on the mucus produced by the hard coral, gathering
these with the minute comb-like structures at the tips of their feet.
The Red coral crab (Trapezia cymodoce)
lives only in Cauliflower
corals (Pocillopora sp.). The crab protects the coral from
predators such as the Crown-of-Thorns sea star. It discourages the
sea star by using its sharp pincers to nip at the sensitive tube feet
of the sea star.
The Bandit coral crab (Tetralia nigrolineata)
lives only Acropora
corals (Acropora sp.).
Other tiny crabs that live in corals
include the Hairy coral crab (Cymo
Status and threats: The Red coral
crab (Trapezia cymodoce) is listed as 'Vulnerable' in our Red
List of threatened animals of Singapore. To protect these crabs, we
need to protect their hard coral homes.
Trapezioidea recorded for Singapore
Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity
Leo W. H. & Ng, Peter K. L., 1988. A Guide to Seashore Life.
**from Lim, S., P. Ng, L. Tan, & W. Y. Chin, 1994. Rhythm of the
Sea: The Life and Times of Labrador Beach.
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.
- 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.
- Wee Y.C.
and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore.
National Council on the Environment. 163pp.
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.