Variegated scallop (Mimachlamys varia)

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

Summary

Description

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.

Habitat

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

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Bibliography

  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.), 1995. 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] http://www.jncc.gov.uk/mermaid

  5. 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.

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

Datasets

  1. Centre for Environmental Data and Recording, 2018. IBIS Project Data. Occurrence dataset: https://www.nmni.com/CEDaR/CEDaR-Centre-for-Environmental-Data-and-Recording.aspx accessed via NBNAtlas.org on 2018-09-25.

  2. Centre for Environmental Data and Recording, 2018. Ulster Museum Marine Surveys of Northern Ireland Coastal Waters. Occurrence dataset https://www.nmni.com/CEDaR/CEDaR-Centre-for-Environmental-Data-and-Recording.aspx accessed via NBNAtlas.org on 2018-09-25.

  3. Cofnod – North Wales Environmental Information Service, 2018. Miscellaneous records held on the Cofnod database. Occurrence dataset: https://doi.org/10.15468/hcgqsi accessed via GBIF.org on 2018-09-25.

  4. Conchological Society of Great Britain & Ireland, 2018. Mollusc (marine) data for Great Britain and Ireland - restricted access. Occurrence dataset: https://doi.org/10.15468/4bsawx accessed via GBIF.org on 2018-09-25.

  5. Conchological Society of Great Britain & Ireland, 2023. Mollusc (marine) records for Great Britain and Ireland. Occurrence dataset: https://doi.org/10.15468/aurwcz accessed via GBIF.org on 2024-09-27.

  6. Fenwick, 2018. Aphotomarine. Occurrence dataset http://www.aphotomarine.com/index.html Accessed via NBNAtlas.org on 2018-10-01

  7. Fife Nature Records Centre, 2018. St Andrews BioBlitz 2015. Occurrence dataset: https://doi.org/10.15468/xtrbvy accessed via GBIF.org on 2018-09-27.

  8. Kent Wildlife Trust, 2018. Kent Wildlife Trust Shoresearch Intertidal Survey 2004 onwards. Occurrence dataset: https://www.kentwildlifetrust.org.uk/ accessed via NBNAtlas.org on 2018-10-01.

  9. Merseyside BioBank., 2018. Merseyside BioBank (unverified). Occurrence dataset: https://doi.org/10.15468/iou2ld accessed via GBIF.org on 2018-10-01.

  10. Merseyside BioBank., 2018. Merseyside BioBank Active Naturalists (unverified). Occurrence dataset: https://doi.org/10.15468/smzyqf accessed via GBIF.org on 2018-10-01.

  11. National Trust, 2017. National Trust Species Records. Occurrence dataset: https://doi.org/10.15468/opc6g1 accessed via GBIF.org on 2018-10-01.

  12. NBN (National Biodiversity Network) Atlas. Available from: https://www.nbnatlas.org.

  13. Norfolk Biodiversity Information Service, 2017. NBIS Records to December 2016. Occurrence dataset: https://doi.org/10.15468/jca5lo accessed via GBIF.org on 2018-10-01.

  14. OBIS (Ocean Biodiversity Information System),  2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2024-12-27

  15. South East Wales Biodiversity Records Centre, 2018. SEWBReC Molluscs (South East Wales). Occurrence dataset: https://doi.org/10.15468/jos5ga accessed via GBIF.org on 2018-10-02.

Citation

This review can be cited as:

Oakley, J.A. 2007. Mimachlamys varia Variegated scallop. In Tyler-Walters H. and Hiscock K. Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 27-12-2024]. Available from: https://marlin.ac.uk/species/detail/2086

Last Updated: 03/07/2007