The Oligocene mollusc types of Gaetano Rovereto from Santa Giustina and Sassello (NW Italy)

The present paper examines the type specimens of the bivalve and gastropod taxa described by Gaetano Rovereto in the years 1897-1914 coming from the Oligocene rocks of Santa Giustina and Sassello areas (Molare Formation, Tertiary Piedmont Basin, Central Liguria, NW Italy). These taxa are part of the "Collezione BTP" (BTP Collection) housed at the Dipartimento di Scienze della Terra, dell'Ambiente e della Vita DISTAV of the Universita di Genova. The collecting sites reported in the Rovereto's papers and indicated on labels have been reinvestigated in the field. 22 taxa (6 gastropods and 16 bivalves) are revised and re-documented; 6 have been recognized as younger synonyms of other species, the others are valid taxa. The majority of this fauna is restricted to the Oligocene time and to the Tertiary Piedmont Basin.