Seven-rayed scallop (Pseudamussium peslutrae)

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



A bivalve with a brittle, scallop-shaped shell up to 5 cm in length. Both valves are similar in size and shape but are slightly asymmetrical. The animal lives with its left valve facing upwards. The left (upper) valve is brick-red or purplish brown, with white or cream spots and blotches. The right valve is dirty white or pale brick-red near the umbones (depending on size) and down the ribs, and is slightly more convex than the left valve. Each valve has 3-10 (most commonly 5-8) evenly spaced, broad, rounded ribs that increase rapidly in width from the umbone to the margin.

Recorded distribution in Britain and Ireland

Recorded sparsely around the British Isles but most common off the west coast of Scotland and north of the North Sea.

Global distribution

Pseudamussium peslutrae is recorded from southern Iceland, the Faroes and northern Norway and then south to the Mediterranean and north-west Africa.


Pseudamussium peslutrae is free living, inhabiting muddy mixed sediments offshore to about 300 m in depth.

Depth range

Offshore to up to 300 m.

Identifying features

  • Almost circular but scallop-shaped in outline. 
  • Shell can be up to 5 cm but commonly up to 3.8 cm in length.
  • Both valves are similar in size and shape (equivalve).
  • Valves are slightly asymmetrical (inequilateral).
  • Left (upper) valve is brick-red or purplish brown and mottled white.
  • Right (lower) valve is white or coloured reddish near the umbones and down the ribs.
  • Ears of shell with 4-6 ribs radiating from the beak and numerous folded striae running parallel to median line of shell.

Additional information

Pseudamussium peslutrae is variable in shape, colour and structure (sculpture). Juveniles closely resemble Pseudamussium sulcatum but Pseudamussium sulcatum is more coarsely sculptured.

Listed by

- none -


  1. De Kluijver, M.J., Ingalsuo, S.S. & de Bruyne, R.H., 2021. Mollusca of the North Sea. Marine Species Information Portal. Leiden, The Netherlands: ETI Bioinformatics.  Available from:

  2. Dijkstra, H.H., Warén, A. & Gudmundsson, G., 2009. Pectinoidea (Mollusca: Bivalvia) from Iceland. Marine Biology Research, 5 (3), 207-243. DOI

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

  4. Hayward, P.J. & Ryland, J.S. (ed.) 1995b. Handbook of the marine fauna of North-West Europe. Oxford: Oxford University Press.

  5. Hayward, P.J. & Ryland, J.S. (ed.) 2017. Handbook of the marine fauna of North-West Europe. Oxford: Oxford University Press.

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


  1. Conchological Society of Great Britain & Ireland, 2018. Mollusc (marine) records for Great Britain and Ireland. Occurrence dataset: accessed via on 2018-09-25.

  2. NBN (National Biodiversity Network) Atlas. Available from:

  3. OBIS (Ocean Biodiversity Information System),  2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. Accessed: 2024-05-18


This review can be cited as:

Lloyd, K.A., 2021. Pseudamussium peslutrae Seven-rayed scallop. In Tyler-Walters H. Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 18-05-2024]. Available from:

Last Updated: 27/09/2021