Description: This bivalve has a brittle, unequal shell, with the right valve more convex than the left. The beak of one valve often punctures the other. The shell is white with a brown to red-brown periostracum, and reaches around 2.5 cm in length. It is broadly oval in outline with the anterior margin rounded and posterior straight and becoming truncated. The outside of the shell is covered in smooth concentric lines and ridges and has a coarse granular surface which feels slightly rough to the touch. There are no teeth on the hinge line. The inside of the shell is white with a deep pallial sinus that reaches the anterior line of the resilifer.

Habitat: Coarse sand, and fine to coarse gravel. Found from low water down to around 60 m depth.

Distribution: Found all around Britain and Ireland.

Similar Species: Could be confused with Thracia phaseolina or Ixartia distorta.

Key Identification Features:

• Brittle, broadly oval shell up to 2.5 cm.
• Anterior margin rounded, posterior straight becoming truncated.
• Outside of shell coarse and granular, feeling slightly rough to the touch.
• No teeth at hinge line.
• Deep pallial sinus reaching anterior line of resilifer.

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

iNaturalist: Thracia villosiuscula at iNaturalist World Species Observations database.

GBIF data for Thracia villosiuscula

WoRMS: Thracia villosiuscula at World Register of Marine Species. Accepted name: Thracia villosiuscula (MacGillivray, 1827). AphiaID: 141651.

Classification: Biota; Animalia; Mollusca; Bivalvia; Autobranchia; Heteroconchia; Euheterodonta; Anomalodesmata; Thracioidea; Thraciidae; Thracia