Biodiversity & Conservation

Bearded mussel - Modiolus barbatus

Modiolus barbatus

Image Steve Trewhella - The bearded mussel Modiolus barbatus. Image width ca 3 cm.
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Distribution map

Modiolus barbatus 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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Modiolus barbatus is not listed under any importance categories.

Taxonomy icon Taxonomy Taxon English term
Phylum Mollusca Snails, slugs, mussels, cockles, clams & squid
Class Bivalvia Clams, cockles, mussels, oysters, and scallops
Authority (Linnaeus, 1758)
Recent synonyms None
Map icon Recorded Distribution in Britain and Ireland Mainly recorded on the south and west coasts of Britain and Ireland but also found at sites east of the Shetland Islands, in the North Sea, on the north-east coast of England, the east coast of Ireland and in the Irish Sea.
Habitat information icon Habitat information This species is found among rocks and stones on the lower shore, extending into the sublittoral to depths of around 100 m.
Text page icon Description Modiolus barbatus can grow up to 6 cm long, although individuals are usually smaller. The shell is an elongate oval shape with the hinge line at a steep angle to the prominent, rounded umbones. The beaks are not quite at the anterior end of the shell. The outer surface of the shell is yellowish-white, light yellow or reddish-brown in colour. Over the posterior half of the shell the periostracum bears long, flat bristles, each with a distinctly serrated edge. The inner surface of the shell is shiny and pale blue in colour.
Identifying features
  • Elongate oval or rhomboidal shaped shell.
  • Umbones subterminal, above a curved anterior margin.
  • Hinge line acute to umbones and without teeth.
  • Umbonal ridges very prominent, rounded and almost parallel with the ventral margin.
  • Periostracum yellowish-white, yellow or reddish-brown and developed into serrated spines on the posterior part of the shell.
  • Inner surface of shell shiny, blueish-white, tinged red or light purple.
Additional information icon Additional information Modiolus barbatus is also known as the bearded horse mussel.

This review can be cited as follows:

Caroline Farrell 2006. Modiolus barbatus. Bearded mussel. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 25/05/2013]. Available from: <http://www.marlin.ac.uk/speciesinformation.php?speciesID=3816>