Biodiversity & Conservation

Sand gaper - Mya arenaria - General information

Mya arenaria

Image Dr Matthias Strasser - A selection of adult Mya arenaria. Image width ca 40 cm.
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Distribution map

Mya arenaria recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

Why do the maps differ?

Sightings Have you seen Mya arenaria?
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Mya arenaria is not listed under any importance categories.

General information

Key Icon Researched by: Dr Harvey Tyler-Walters Text page icon Refereed by: Dr Matthias Strasser

Taxonomy icon Taxonomy

Phylum Mollusca Snails, slugs, mussels, cockles, clams & squid
Class Bivalvia Clams, cockles, mussels, oysters, and scallops
Map icon Recorded distribution in Britain and Ireland Found on all British coasts but is not recorded from the Isles of Scilly.
Habitat information icon Habitat information Mya arenaria lives in burrows up to 50 cm deep in sand, mud, sandy mud, and sandy gravels from the mid shore to the shallow sublittoral, sometimes to a depth of 192 m. Often abundant on estuarine flats where it can survive at salinities as low as 4-5 psu.
Text page icon Description Mya arenaria is a large long-lived bivalve. The shell is dirty white or fawn in colour with a fawn or light yellow periostracum. Large specimens may reach 12 -15 cm in length. The shell is oval in outline, marked by conspicuous concentric lines with dissimilar valves, the right being slightly more convex than the left, and slightly anterior beaks (umbones). The shell gapes posteriorly. The shell hinge bears no teeth but the left valve bears a large spoon shaped chondrophore to which the ligament is attached. However, there is considerable variation in shell outline, texture and thickness. The interior of the shell is white with a deep pallial sinus, and anterior and posterior adductor muscle scars. The foot is small and muscular and the mantle edges are fused except at the pedal gape and ends of siphons. The exhalent and inhalent siphons are fused along their length, contractile, and capable of considerable extension to reach the surface (about 20cm or up to 40cm in large specimens) where they leave a characteristic 'key-hole' shaped opening in the sediment.

This review can be cited as follows:

Dr Harvey Tyler-Walters 2003. Mya arenaria. Sand gaper. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 22/05/2012]. Available from: <http://www.marlin.ac.uk/speciesfullreview.php?speciesID=3839>