Marbled crenella (Musculus subpictus)

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



Modiolarca tumida is a small bivalve up to 2 cm in length. The valves of the shell are equal in size, shape and depth and both have a swollen, plump appearance. The shell is broadly oval in outline. The shell is yellow with ribs in the anterior and posterior regions. The periostracum is light green, with blotches of brown, red-brown or purple. The margin of the shell is smooth but crenulate where it meets the ribs. The inside of the shell is bright white.

Recorded distribution in Britain and Ireland

Recorded from the Shetland Isles, Orkney, south east Scotland, the Northumberland coast, and the south west and west coasts of England and Scotland, with a few records from Ireland.

Global distribution



On rocky shores in the low intertidal, buried in the test of Ascidia mentula or Ascidiella aspersa, in and amongst kelp holdfasts, under rocks and stones.

Depth range


Identifying features

  • Shell yellow with a light green periostracum.
  • Anterior end of shell with 15-18 radiating ribs, posterior end with 20-35 ribs.

Additional information

No text entered

Listed by

- none -


  1. Bruce, J.R., Colman, J.S. & Jones, N.S., 1963. Marine fauna of the Isle of Man. Liverpool: Liverpool University Press.

  2. Crothers, J.H. (ed.), 1966. Dale Fort Marine Fauna. London: Field Studies Council.

  3. Foster-Smith, J. (ed.), 2000. The marine fauna and flora of the Cullercoats District. Marine species records for the North East Coast of England. Sunderland: Penshaw Press, for the Dove Marine Laboratory, University of Newcastle upon Tyne.

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

  5. 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.]

  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., 1966. British Bivalve Seashells. A Handbook for Identification. Edinburgh: British Museum (Natural History), Her Majesty's Stationary Office.


  1. Centre for Environmental Data and Recording, 2018. Ulster Museum Marine Surveys of Northern Ireland Coastal Waters. Occurrence dataset accessed via on 2018-09-25.

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

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

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

  5. OBIS (Ocean Biodiversity Information System),  2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. Accessed: 2024-06-23


This review can be cited as:

Neal, K.J. 2004. Musculus subpictus Marbled crenella. 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 23-06-2024]. Available from:

Last Updated: 24/09/2004