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Phylum Arthropoda > Subphylum Crustacea > Class Malacostraca > Order Decapoda > Brachyurans > Family Portunidae
Mud crab
Scylla sp.
Family Portunidae

updated Oct 2016
Where seen? This enormous crabs is among our favourite seafood. It is seldom seen and is usually hidden in its burrow in the mangroves. Sometimes, large individuals are seen in other habitats. These are likely to be fully grown adults that were taken from seafood markets and released as part of religious rituals, unfortunately, usually in unsuitable habitats.

Features: Body width to about 20cm. Body somewhat fan-shaped with 9 spines on the sides but the last tooth is not enlarged as it is in flower crabs.
Mud crabs belong to the same family as swimming crabs and their last pair of legs are paddle-shaped. But because they are such large, heavy crabs, they don't use these legs to swim. Instead, the legs are used like spades to burrow with. Unlike flower crabs, mud crabs are able to stay out of water for some time. They come in various colours ranging from dark green (mostly those from mangroves) to bluish green (those found in open waters).

There are three species of mud crabs found in Singapore.

The Green mud crab (S. paramamosain): body width to about 15cm with orange and green pincers and very sharp teeth between the eyes.

The
Orange mud crab (S. olivacea): body width to about 18cm with orange pincers.

The Purple mud crab (S. tanquebarica): body width to about 20cm with distinct purple pincers.

The Mud crab we often eat at restaurants are actually from the Giant mud crab (Scylla serrata) which can grow to about 28cm. These come from Sri Lanka (thus sometimes also called the Sri Lankan crab). This crab is not found in Singapore.


What does it eat? This crab is a predator and will eat any animal that it can catch. It appears to prefer snails and clams.

Human uses: These crabs are edible and a favourite dish for many Singaporeans. They are traditionally caught by hooking them out of their burrows with long iron rods.

It is better known as Chilli crab!


Chek Jawa, Nov 09

Changi, Jul 07

Tanah Merah, Oct 10

Sentosa, Nov 11

Mud crabs on Singapore shores

Photos of Mud crabs for free download from wildsingapore flickr

Distribution in Singapore on this wildsingapore flickr map


Punggol, Jun 12
Photo shared by Loh Kok Sheng on flickr.

Pasir Ris Park, Nov 08
Photo shared by Loh Kok Sheng on his blog.
 

 

Pulau Sekudu, Jun 14
Photo shared by Marcus Ng on facebook.


Pulau Tekukor, May 10
Photo shared byGeraldin Lee on her blog.

Pulau Semakau, Dec 08
Photo shared by Marcus Ng on his blog.

Pulau Pawai, Dec 09

Links References
  • Kelvin K. P. Lim. 3 October 2014. Orange mud-crab at Pasir Ris mangrove, Scylla olivacea. Singapore Biodiversity Records 2014: 270.
  • 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.
  • Ng, P. K. L. & Y. C. Wee, 1994. The Singapore Red Data Book: Threatened Plants and Animals of Singapore. The Nature Society (Singapore), Singapore. 343 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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