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Phylum Arthropoda > Subphylum Crustacea > Class Malacostraca > Order Decapoda > Brachyurans > Superfamily Trapezioidea
Red coral crab
Trapezia cymodoce

Family Trapeziidae
updated Dec 2019

Where seen? This tiny red crab is sometimes seen in Cauliflower corals (Pocillopora sp.) on our Southern shores.

Features: Body width about 1cm, body flat, claws large with pointed pincers usually dark at the tips. Usually red or dark orange. Often, more than one crab is seen in a single colony. They are hard to spot and photograph.

This crab lives only in Cauliflower corals (Pocillopora sp.). The crab feeds on the mucus produced by the coral, gathering these with the minute comb-like structures at the tips of their feet. In turn, it protects the coral from predators such as the Crown-of-Thorns sea star and sea snails that eat corals. It discourages the sea star by using its sharp pincers to nip at the sensitive tube feet of the sea star.

Status and threats: The Red coral crab is listed as 'Vulnerable' in our Red List of threatened animals of Singapore.

Cyrene Reef, Jul 10

Sentosa Serapong, Dec 20
Photo shared by Vincent Choo on facebook.

Sentosa Serapong, May 12
A pair in the Cauliflower coral.

Cyrene Reef, Jul 10

A pair in a bleaching Cauliflower coral.

Red coral crabs on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores

Tanah Merah, May 10

Tanah Merah Ferry Terminal, Jun 22
Photo shared by Kelvin Yong on facebook.

Sentosa Tg. Rimau, Jan 20
Photo shared by Kelvin Yong on facebook.

Lazarus Island, Jan 24
Photo shared by Vincent Choo on facebook.

Cyrene Reef, Feb 16
Photo shared by Marcus Ng on facebook.

Pulau Hantu, Jun 10
Photo shared by Loh Kok Sheng on his blog.

Pulau Semakau South, Jul 15
Photo shared by Neo Mei Lin on her blog.

Terumbu Pempang Laut, Apr 11
Photo shared by Loh Kok Sheng on his blog.



  • Astri Noorbaini Samsuri, Yuichi Preslie Kikuzawa, Daisuke Taira, Shu Qin Sam, Wan Ting Sim, Chin Soon Lionel Ng, Lutfi Afiq-Rosli, Teck Wei Delon Wee, Ngan Kee Ng, Tai Chong Toh, Loke Ming Chou. 27 March 2018. The effectiveness of Trapezia cymodoce in defending its host coral Pocillopora acuta against corallivorous Drupella. Marine Biology April 2018, 165:70
  • 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.
  • 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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