Description: This bivalve has a brittle shell with a broadly oval outline, and smooth concentric lines on the outer surface. The valves are not equal - the right valve is slightly larger than the left and more convex which causes a slight overlap. Shell may gap slightly. The shell is white but may be covered in places by the periostracum which is can be fawn to light yellow. The umbo has an irregular crack, next to which there is a granular area and sand is often stuck here. Interior of the shell is white and there is a prominent resilifer.

Habitat: Sand, muddy sand and gravel. Found from low water mark to over 100 m depth.

Distribution: Recorded all around Britain and Ireland, but appears rare on south and southwest coast of Ireland.

Similar Species: With some experience identifying bivalves, this is unlikely to be confused with any other species.

Key Identification Features:

• Right valve larger than left, and more convex, causing overlap.
• Umbonal crack.

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

iNaturalist: Cochlodesma praetenue at iNaturalist World Species Observations database.

GBIF data for Cochlodesma praetenue

WoRMS: Cochlodesma praetenue at World Register of Marine Species. Accepted name: Cochlodesma praetenue (Pulteney, 1799). AphiaID: 181373.

Classification: Biota; Animalia; Mollusca; Bivalvia; Autobranchia; Heteroconchia; Euheterodonta; Anomalodesmata; Thracioidea; Periplomatidae; Cochlodesma