Description: This bivalve grows up to 25 mm, is broadly oval in shape and the valves are almost equal. It has a brittle, glossy white shell, although this may be covered, at least in part, by light brown periostracum. Growth stages are clear, indicated by fine concentric lines visible on the surface of the valves. The interior of the shell is white and the pallial sinus is deep and irregular in shape. The right valve has two small cardinal teeth and single posterior and anterior lateral teeth; the left valve has one cardinal tooth and very weak single anterior and posterior lateral teeth, appearing only as thickened sections of the dorsal margin.

Habitat: Soft substrata (e.g. mud, silty sand and soft muddy gravel) especially in shallow offshore areas. May also occasionally be found on the lower shore.

Distribution: Recorded around all coasts of Britain and Ireland. Abundant in some locations.

Similar Species: There are other superficially similar looking bivalves and other species of Abra found in Britain and Ireland. These can be distinguished by the presence (or not) of lateral teeth, the shape of the shell and visibility of growth stages.

Key Identification Features:

• Brittle glossy white shell, which may be partially covered by light brown periostracum.
• Grow stages are clear (fine concentric lines).
• Lateral teeth present.
• Pallial sinus deep and irregular in shape.

Distribution Map from NBN: Abra alba at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Abra alba at iNaturalist World Species Observations database.

GBIF data for Abra alba

WoRMS: Abra alba at World Register of Marine Species. Accepted name: Abra alba (W. Wood, 1802). AphiaID: 141433.

Classification: Biota; Animalia; Mollusca; Bivalvia; Autobranchia; Heteroconchia; Euheterodonta; Imparidentia; Cardiida; Tellinoidea; Semelidae; Abra