Chemosynthetic bivalves of the family Solemyidae (Bivalvia, Protobranchia) in the neogene of the Mediterranean basin

The Mediterranean area is the locus of a variety of deep-sea chemosynthetic environments that have been exploited by bivalves of the family Solemyidae during Cenozoic to present time. Large solemyids represented by the Solemya doderleini group were widely distributed in Neogene deep-sea reducing habitats, including cold vent hydrocarbon sites. Based upon the diagnostic structure of the ligament, Solemya doderleini (Mayer), 1861 and S. subquadrata (Foresti), 1879 are moved to the genus Acharax Dall, 1908. After the Messinian Salinity Crisis Acharax doderleini re-colonized deep-sea sulphide environments up to the Pliocene at least. At present, Acharax occurs in similar settings in the adjacent eastern Atlantic Ocean. Thus far, large solemyids are not documented from the present deep Mediterranean Sea in spite of a vast number of seep and reducing habitats with chemosynthetic biota, especially concentrated in its Eastern basin. Promisingly, however, a single live juvenile specimen of Solemyidae has been recently found at bathyal depth associated with a pockmark in the Nile Deep Sea Fan.