A new fossil sirenian (Mammalia, Dugonginae) from the miocene of India

Abstract

Kutchisiren cylindrica, n. gen. n. sp., is a dugongine sirenian represented by a single skull with mandible from the Lower Miocene (Aquitanian or Burdigalian) Khari Nadi Formation in the district of Kutch (= Kachchh), Gujarat State, western India. It is characterized by a braincase of nearly cylindrical form, a strong rostral deflection of about 78°, and a large upper incisor tusk with a lozenge-shaped cross section. It evidently coexisted with at least two other dugongine taxa: Bharatisiren kachchhensis and Domningia sodhae. These three forms differed in rostral deflection, body size, and other details of skull and tusk morphology that apparently enabled them to partition the available marine seagrass resources. Their exact phylogenetic relationships, however, remain unresolved for now.