Miocene dugongid (Mammalia, Sirenia) diversity in the Indian Ocean, with description of a new genus and species from Kutch, Western India

A new dugongine (Kharisiren cristata gen. et sp. nov.) is described here based on a partial skull from the Lower Miocene of Kutch, Gujarat state, western India. The new taxon is characterized, among other features, by an anteriorly sloping frontonasal roof with a pair of ridges on either side of the midline suture, a massive, sub-horizontal nasal process of the premaxilla; rostral deflection of about 45°, pentagonal outline of the mesorostral fossa with a U-shaped posterior margin, and an upper incisor tusk with a lozenge- or kite-shaped cross section. The study also briefly describes key features in the partially encased endocast in this taxon. The new dugongine coexisted with four other dugongines—Bharatisiren indica, B. kachchhensis, Kutchisiren cylindrica, Domningia sodhae—suggesting considerable evolutionary diversification and specialized niche partitioning during the Early Miocene in the Indian Ocean region. The Miocene dugongids of the Indian Ocean, including dugongines from India and Madagascar, share morphological similarities that suggest potential paleobiogeographic influences on their diversification. This implies a close relationship between these faunas, likely due to their geographic proximity, and highlights the ability of early dugongids to cross large oceanic barriers.