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Phylum Arthropoda > Subphylum Crustacea > Class Malacostraca > Order Decapoda > Brachyurans > Family Portunidae
Powder blue-clawed swimming crab
Thalamita crenata*
Family Portunidae
updated Oct 2016
Where seen? This swimming crab with powder blue pincers is sometimes seen near seagrasses and reefs on some of our shores. Elsewhere, they are also found in mangroves and soft-silty bottoms near rocky areas without reefs.

Features: Body width 5-7cm. Body somewhat rectangular, the sides of the body with 5 light blue-light brown tipped spines of about equal size. The eyes are wide apart. Between the eyes are 6 small rounded lobes. Walking legs greenish or bluish with orange joints and orange or red tips. Last pair of legs are paddle-shaped. Body and pincers sand coloured, plain light olive or pinkish, The body edge may have a fine powder blue-brown banded pattern. The pincers are powder blue with dark red tips.

Human uses:
Harvested elsewhere by traps, trawling and nets although it is not as commercially valuable as other swimming crabs.

Tanah Merah, Sep 09

Tanah Merah, Jul 10
Photo shared by Marcus Ng on flickr.

6 small rounded lobes between the eyes.

5 spines on the body side,
edged with small blue and dark spots.

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

Powder blue-clawed swimming crabs on Singapore shores

Photos of Powder blue-clawed swimming crabs for free download from wildsingapore flickr

Distribution in Singapore on this wildsingapore flickr map


A pair about to mate?
Punggol, Jun 12

Mating pair
Tuas, Dec 14

Photo shared by Jianlin Liu on facebook.

East Coast-Marina Bay, Oct 15
Photo shared by Loh Kok Sheng on flickr.


Berlayar Creek, Oct 15
Photo shared by Marcus Ng on flickr.

Seringat-Kias, Aug 15
Photo shared by Loh Kok Sheng on flickr.


Mating pair
Pulau Semakau, Dec 08

Photo shared by Marcus Ng on flickr.

St John's Island, Nov 15
Photo shared by Marcus Ng on facebook.

   Links References
  • 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.
  • 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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