Cenozoic Corbulidae (Bivalvia, Mollusca) from the Indian subcontinent—palaeobiogeography and revision of three species from Kutch, India

Three corbulid species were discriminated from the Cenozoic strata of Kutch, India. Two of them are Caestocorbula gujaratensis n. sp. and Bicorbula kutchensis n. sp. from the Palaeocene to Middle Eocene. The other species, Corbula trigonalis Sowerby, from the Lower Miocene is reassigned to Lenticorbula. The two new species co-occur in the same horizons. Palaeobiogeographical distribution of molluscs in general and corbulids in particular in the Indian subcontinent, especially of India and Pakistan, reveals high endemism. The distribution also evinces palaeobiogeographical closeness among the western Indian basins and Pakistan, thus entailing their inclusion in the same province. This province shows similarity in faunal composition with Africa and Middle East during the Lower Palaeogene whereas with southeast Asian basins during the Miocene. The pattern reflects a shift in biogeographical affinity of the province from Tethyan to Indo-Pacific.