Shell equivalve, almost equilateral. Outline subcircular with posterior margin subangular. Taxodont hinge strongly arched; up to 12 teeth anteriorly, up tp 14 teeth posteriorly. Sculpture of about 30 low ribs with narrow interspaces. All ribs incised by radial grooves. Inner margin crenulate. Periostracum bearing bristles.
shell externally white with beige, brown to reddish-brown spots; internally usually with a dark brown-black posterior-ventral area.
common size :
shell to 30 mm.
The anterior margin is protruding, giving the shell a somewhat oblique shape. This distortion from circular, the infated shell and the small size are diagnostic features for the species.
BIOLOGY / ECOLOGY
Epifaunal, actively mobile, suspension feeders.
shallow water sands (Oliver, 1992). In the Mediterranean dredged from a depth of 46 m.