Elongated furrow shell (Abra prismatica)

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



A bivalve with a thin and brittle oval shell up to 2.5 cm in length, and twice as long as it is deep. Both valves are similar in size and shape but are asymmetrical with the beak positioned in the posterior half of the shell pointing inwards and backwards. The outer and inner surfaces of the shell are glossy white, but the outside of the shell is covered with a brown layer (periostracum). The outside of the shell bears fine concentric lines. The inside of the shell has a pit (chondrophore) near the beak. The body bears a large and pointed foot and two slender siphons.

Recorded distribution in Britain and Ireland

Widespread around the coasts of Britain but rarely present on the western coast of Ireland.

Global distribution

Abra prismatica is widespread in the North Sea, from Norway to the Mediterranean and northwest Africa. It is also found along the south and west coasts of Iceland and the Faroes.


Abra prismatica inhabits burrows in mixed sandy bottoms (clean sand, fine sand, and muddy sand) in the sublittoral zone from the low-water mark to about 280 m.

Depth range

Lower shore to 280 m depth

Identifying features

  • Elongated oval in outline.
  • Shell up to 2.5 cm in length and twice as long as it is deep.
  • Shell bears fine concentric lines, visible with a hand lens.
  • Both valves of the shell are similar in size and shape (equivalve).
  • Valves are asymmetrical front-to-back (inequilateral).
  • Both the outer and inner surface of the shell is glossy white.
  • Right valve has two cardinal teeth, left valve has one small cardinal tooth.
  • The periostracum is brown.

Additional information

Abra prismatica is similar to Abra alba and Abra nitida but has a more elongated shell and the top shell shifts greatly to the posterior margin of the valve. Juveniles resemble another bivalve species (Macoma calcarea) but differ with a more elongated shell, shifted top, and presence of internal ligament. Abra prismatica feeds on surface detritus.

Listed by

- none -


  1. Conchological Society of Great Britain & Ireland, 2021. Molluscs. Species accounts. Conchological Society of Great Britain & Ireland. Available from: https://conchsoc.org/encyclopedia 

  2. 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: http://species-identification.org/species.php?species_group=mollusca&menuentry=inleiding

  3. Deart, Y.V., Frolov, A.A. & Manushin, I.E., 2013. Bivalves Abra prismatica (Montagu, 1808) and Gari fervensis (Gmelin, 1791) — Species new to the fauna of the Russian sector of the Barents Sea. Russian Journal of Biological Invasions, 4 (3), 139-148. DOI https://doi.org/10.1134/S2075111713030028

  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. Oliver, P.G., Holmes, A.M., Killeen, I.J. & Turner, J.A., 2016. Marine Bivalve Shells of the British Isles. Amgueddfa Cymru - National Museum Wales. Available from: http://naturalhistory.museumwales.ac.uk/britishbivalves [Cited:  3 July 2018].

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


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

  2. OBIS (Ocean Biodiversity Information System),  2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2024-06-15


This review can be cited as:

Lloyd, K.A., 2021. Abra prismatica Elongated furrow shell. 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 15-06-2024]. Available from: https://marlin.ac.uk/species/detail/2339

Last Updated: 21/09/2021

  1. Bivalve
  2. Mollusc
  3. elongate furrow shell