Biodiversity & Conservation

Masked crab - Corystes cassivelaunus

Corystes cassivelaunus

Image Sue Daly - Male Corystes cassivelaunus in the Channel Isles.
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Distribution map

Corystes cassivelaunus recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

Why do the maps differ?

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Corystes cassivelaunus is not listed under any importance categories.

Taxonomy icon Taxonomy Taxon English term
Phylum Arthropoda Arthropods, joint-legged animals, e.g. insects, crustaceans & spiders
Class Malacostraca Crabs, lobsters, sand hoppers and sea slaters
Authority (Pennant, 1777)
Recent synonyms None
Map icon Recorded Distribution in Britain and Ireland A southern species recorded on many British coasts but absent from much of northern Scotland.
Habitat information icon Habitat information Typically found in burrows in the sand from the lower shore and shallow sublittoral to about 100 m.
Text page icon Description Corystes cassivelaunus is easily recognised by its elongate, ovoid carapace (up to 4 cm long and 3 cm wide). It is a reddish-brown to yellow in colour. The chelipeds of the male are twice the length of the carapace while those of the female are much smaller. There are 2 teeth between the eyes and the lateral margin has 4 teeth (of which the second is the largest). While buried, the crab's antennae are brought together and the setae interlock to form a respiratory tube.
Identifying features
  • Short rostrum.
  • Dorsal surface minutely granulated.
  • Ridges on carapace can sometimes resemble a face.
  • Antennae longer than carapace and heavily covered with setae.
Additional information icon Additional information

This review can be cited as follows:

Marie Skewes 2008. Corystes cassivelaunus. Masked crab. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 19/05/2013]. Available from: <http://www.marlin.ac.uk/speciesinformation.php?speciesID=3074>