2-3 mm

Habitat: it seems it prefers either slimy or sandy-slimy bottoms.
Distribution: common all over the Mediterranean, even in remarkable depths. It is considered a cosmopolite species. Notes: shell brittle, equivalve, inequilateral, suboval in outline, wider rather than higher. Adult specimens are covered by a ferrugineous covering hiding shells details. Posterior margin stretched and bent making one rounded angle once it meets the ventral margin. Ventral margin and anterior margin rounded in form. Umbo protuberant and projected anteriorly. Sculpture made by fine concentric striae. Valves, without crusts, are dirty white in colour. Inside of valves translucent. Juvenile specimens are more rounded in outline. It can be seldom confused with the other Thyasiridae, at least for its peculiar covering red-brown in colour. The adult specimens average measures are around 3 mm in length.