Biodiversity & Conservation

Toad crab - Hyas coarctatus

Hyas coarctatus

Image Hilmar Hinz - Hyas coarctatus specimen 18 mm long. Image width ca XX cm.
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Distribution map

Hyas coarctatus recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

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Hyas coarctatus 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 Leach, 1815
Recent synonyms None
Map icon Recorded Distribution in Britain and Ireland Found throught the British Isles but absent from the west coasts of Ireland.
Habitat information icon Habitat information The toad crab is a benthic species found on both hard and sandy bottoms from the intertidal region down to a depth of up to 50 m.
Text page icon Description The toad crab, Hyas coarctatus, is a 'true crab' and therby has a heavily calcified, flattened carapace with a short abdomen folded up beneath it. The first appendages form large claws. It is a member of the spider crab family and has long, thin legs, and claws of the same length as the legs. Its stalked eyes are visible from above. Hyas coarctatus can reach up to 61 mm in carapace length and is reddish-brown above and white underneath. It has longer claws than the giant spider crab, Hyas araneus, and the two forward-projecting horns on its head are slightly longer and further apart than those of the giant spider crab.
Identifying features
  • Spider crab up to 61 mm in carapace length.
  • Cornea of the retracted eye is visible from above and not concealed under the orbit.
  • Post-orbital spine is flattened and expanded laterally.
  • Basal antenna segment is less than twice as long as it is wide.
  • Abdominal region is dilated laterally and, with the post-orbital region, forms a harp-shaped shelf.
Additional information icon Additional information No text entered

This review can be cited as follows:

Morvan Barnes 2008. Hyas coarctatus. Toad crab. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 26/05/2013]. Available from: <http://www.marlin.ac.uk/speciesinformation.php?speciesID=3533>