Eutherian mammals from the upper cretaceous (Maastrichtian) intertrappean beds of Naskal, Andhra Pradesh, India

Abstract

Late Cretaceous (Maastrichtian) eutherian mammals are documented from the intertrappean beds of Naskal, Rangareddi District, Andhra Pradesh, India, on the basis of isolated canines, premolars, molars, and mandibular fragments. Besides the previously recorded Deccanolestes hislopi, two additional forms, one with affinities to D. hislopi and a new species, D. robustus, are also described. These mammals are primitive in comparison to North American palaeoryctids in their lack of strong, winged conules and absence of lingual cingula on the upper molars; presence of cristid obliqua at the base of metaconid; and hypoconulid closer to hypoconid than to entoconid. Based on transversely wide upper molars with wide stylar shelf, large parastylar area, paracone and metacone which are high and connate at the base, anteriorly recumbent protocone, tall trigonids and small paraconid on the lower molars, these species are referred to Palaeoryctidae. Most of the similarities between the North American palaeoryctid Cimolestes and Deccanolestes are in symplesiomorphic characters. In a few derived characters, however, Deccanolestes compares well with C. magnus and Procerberus. Deccanolestes and Otlestes share some derived characters indicating a possible phylogenetic relationship. These finds extend the distribution of Laurasian palaeoryctid mammals into India and support faunal exchange between India and Laurasian landmasses in Late Cretaceous times, as was suggested previously by the occurrence of discoglossid and pelobatid frogs, crocodilians, ostracods, and charophytes in the intertrappean biota.