Gibbomodiola adriatica: Shell brittle, globose, equivalve, sub-triangular in outline, ventral margin usually straight, sometimes arched (larnarckianus Locard), sometimes with a prominent umbo near the anterior end (brachypterus Locard). External surface smooth, colour pattern varying from yellow to brown, often with rays of reddish striae lighter ventrally. In the young shells the colour pattern is often an uniform red. Periostracum smooth and bright, yellow-brown in colour. The average measures are around 25-30 mm in length. The young shells outline is similar to the adults one.

Gibbomodiola adriatica: Habitat: this shell lives fixed to submerged objects, by its byssus, on detrital and muddy bottoms, in low depth.
Distribution: never common all over the Mediterranean, known in the Black Sea too.