An updated generic classification of Cenozoic pleurotomariid gastropods, with new records from the Oligocene and Early Miocene of India

Although taxonomically distinct, the Cenozoic pleurotomariids are the bottlenecked remnants of the Mesozoic members of the family in terms of morphology, with only conical forms surviving the end-Cretaceous mass extinction. Here, we propose an updated classification scheme for the Cenozoic representatives of this group, based on data from the entire Cenozoic pleurotomariid fossil record. We consider all conventional as well as several new characters so that this scheme can readily help to distinguish Cenozoic pleurotomariid genera. Following the new classification scheme, a revision of the generic status of Cenozoic species previously assigned to 'Pleurotomaria' Defrance, 1826 is presented. Only a few Cenozoic pleurotomariid gastropods have been reported from the Indian subcontinent. Here we report four species from the Oligocene of the Kutch Basin and the Early Miocene (Burdigalian) of the Dwarka Basin of Gujarat, western India, of which two are described as new: Perotrochus bermotiensis n. sp. in the genus Perotrochus Fischer, 1885, and Entemnotrochus kathiawarensis n. sp., Entemnotrochus cf. bianconii, and Entemnotrochus? sp. 1 in the genus Entemnotrochus Fischer, 1885.