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Phylum Arthropoda > Subphylum Crustacea > Class Malacostraca > Order Decapoda > Brachyurans > Family Portunidae
Purple-legged swimming crab
Charybdis hellerii*
Family Portunidae
updated Oct 2016

Where seen? This swimming crab with purple legs is commonly seen on our Northern shores, rocky areas and rubble. Especially at night.

Features: Body width 5-7cm. Body somewhat fan-shaped, the sides with 6 spines of equal size. The eyes are not very far apart. Last pair of legs are paddle-shaped and rotate like boat propellers, so the crab swims well in all directions. It is a fully marine crab and cannot live long out of water. Body smooth, colours various: yellowish, orange, olive with brownish patch near the eyes, often with a pair of white spots near the base. Walking legs purple. Pincers long orange with black pointed tips.

Pulau Sekudu, Jun 05

6 spines on the side of the body.

Changi, Aug 05
What does it eat? The crab has been seen eating other crabs and clams.

Eating another swimming crab.
Changi, Aug 08

Ate a clam?
Tuas, Apr 05

Mating crabs.
Pulau Sekudu, May 04

*Species are difficult to positively identify without close examination.
On this website, they are grouped by external features for convenience of display.

Purple-legged swimming crabs on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores

Pulau Ubin, Dec 09
Photo shared by Loh Kok Sheng on flickr.

Changi Lost Coast, Jun 22
Photo shared by Loh Kok Sheng on facebook.

Tanah Merah, Jun 16
Photo shared by Loh Kok Sheng on flickr.

Grateful thanks to Crabhunter for confirmation of ID. 

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.
  • 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.
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