Description: A fragile bivalve that is broadly triangular in outline with a large gape at the anterior ventral end of the shell. Both valves are strongly convex. It reaches a maximum length of around 25 mm. It is dull white to yellow with a coarse, light brown periostracum, and there is a sculpture of coarse concentric lines and uneven grooves on the shell surface. There are no teeth on the hinge line. The inside of the shell is a pale white with a deep pallial sinus and a smooth margin.

Habitat: Bores into limestone, sandstone and organic carbonates. Found from the lower shore to the shallow sublittoral.

Distribution: Records are mostly from southern areas in Britain and Ireland, with some records on west coast of Ireland.

Similar Species: Unlikely to be confused with any other species.

Key Identification Features:

• Broadly triangular outline with two strongly convex valves.
• Large anterior ventral gape.
• Dull white to yellow with coarse concentric lines and grooves.

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

iNaturalist: Rocellaria dubia at iNaturalist World Species Observations database.

GBIF data for Rocellaria dubia

WoRMS: Rocellaria dubia at World Register of Marine Species. Accepted name: Rocellaria dubia (Pennant, 1777). AphiaID: 505249.

Classification: Biota; Animalia; Mollusca; Bivalvia; Autobranchia; Heteroconchia; Euheterodonta; Imparidentia; Gastrochaenida; Gastrochaenoidea; Gastrochaenidae; Rocellaria