Potomida littoralis
Potomida littoralis is a species of freshwater bivalve belonging to the family Unionidae. It is sometimes known as black river mussel.
Distribution and habitat
The species is found in southwestern Europe and northwestern Africa. Potomida further east are now assigned to other species.Potomida littoralis typically occurs in the middle to lower river sections, but can occasionally be found in the upper parts of the calcium-rich rivers.