information on the biology of species and the ecology of habitats found around the coasts and seas of the British Isles

Variegated scallop (Mimachlamys varia)

Distribution data supplied by the Ocean Biogeographic Information System (OBIS). To interrogate UK data visit the NBN Atlas.



Mimachlamys varia is known commonly as the variegated scallop. This bivalve mollusc is very variable in colour and ranges from white, pink, red, orange, yellow, purple with all shades in between, often in irregular patterns. Both shell valves are convex, oval in outline, except for the protruding ears, and usually up to 6 cm long. There are 25-35 prominent ribs on the valves, each with spatulate spines. These are especially well developed near the margin. Growth stages are sometimes clear. The shell is solid, inequilateral and inequivalve. The anterior ears are 2-3 times longer than the posterior. A prominent byssal notch is present in the right anterior ear, with fine teeth on the lower border.

Recorded distribution in Britain and Ireland

Widespread all around the coasts of the British Isles and Ireland.

Global distribution

Reported from Denmark to the Iberian Peninsula, the Mediterranean and off the coast of west Africa to Senegal.


Mimachlamys varia lives very low on the shore and sublittorally to about 100 m, either free-living or attached by a byssus. It is usually found on rocky substrata, often in algal holdfasts.

Depth range


Identifying features

  • Shell solid, inequivalve and inequilateral.
  • Anterior ears 2-3 times longer than the posterior.
  • Inequivalve.
  • Prominent byssal notch in the right anterior ear, with fine teeth on lower border.
  • Shell oval in outline except for protruding ears.
  • Usually up to 60 cm in length.
  • Colour very variable.
  • Sculpture of 25-35 prominent ribs.
  • Inner surface of shell glossy, often coloured the same as the exterior.

Additional information

Mimachlamys varia matures as a male, changing sex several times during its life (Hayward et al., 1996).

Listed by

Further information sources

Search on:


  1. Hayward, P., Nelson-Smith, T. & Shields, C. 1996. Collins pocket guide. Sea shore of Britain and northern Europe. London: HarperCollins.

  2. Hayward, P.J. & Ryland, J.S. (ed.) 1995a. The marine fauna of the British Isles and north-west Europe. Volume 2. Molluscs to Chordates. Oxford Science Publications. Oxford: Clarendon Press.

  3. Howson, C.M. & Picton, B.E., 1997. The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]

  4. JNCC (Joint Nature Conservation Committee), 1999. Marine Environment Resource Mapping And Information Database (MERMAID): Marine Nature Conservation Review Survey Database. [on-line]

  5. National Biodiversity Network (NBN) Atlas website. Available from:  Accessed 01 April 2017

  6. Picton, B.E. & Costello, M.J., 1998. BioMar biotope viewer: a guide to marine habitats, fauna and flora of Britain and Ireland. [CD-ROM] Environmental Sciences Unit, Trinity College, Dublin.

  7. Tebble, N., 1976. British Bivalve Seashells. A Handbook for Identification, 2nd ed. Edinburgh: British Museum (Natural History), Her Majesty's Stationary Office.


This review can be cited as:

Oakley, J.A. 2007. Mimachlamys varia Variegated scallop. In Tyler-Walters H. and Hiscock K. (eds) Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 22-09-2018]. Available from:

Last Updated: 03/07/2007