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Phylum Arthropoda > Subphylum Crustacea > Class Malacostraca > Order Decapoda > Brachyurans | Family Calappidae
Reef box crab
Calappa hepatica
Family Calappidae
updated Dec 2019
Where seen? This small boxy crab is rarely seen. Usually near reefs on our Southern shores.

Features: Body width about 4cm. It has small bumps all over its body giving it a beaded look that matches perfectly with the surrounding sand!

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.

Status and threats: This crab is listed as Vulnerable in the Red Data List of threatened animals of Singapore.

Pulau Hantu, Apr 10

Reef box crabs on Singapore shores
On wildsingapore flickr

Seringat-Kias, Apr 12
Photo shared by Loh Kok Sheng on flickr.

Big Sisters Island, Feb 17
Photo shared by Marcus Ng on facebook.

Cyrene Reef, Feb 15
Photo shared by Loh Kok Sheng on flickr.

Cyrene Reef, Apr 23
Photo shared by Loh Kok Sheng on facebook..

Cyrene Reef, May 11

Photo shared by Loh Kok Sheng on flickr.



  • 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.
  • 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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