A new specimen of Anthracokeryx naduongensis (Mammalia, Artiodactyla, Anthracotheriidae) from the Eocene Na Duong Formation, northeastern Vietnam

Abstract

A fossil specimen of Anthracokeryx naduongensis (Mammalia, Artiodactyla, Anthracotheriidae, Microbunodontinae) discovered in the middle/upper Eocene Na Duong Formation at Na Duong Coal Mine in northeastern Vietnam is described. The specimen is a left mandibular fragment preserving p3-m3. It is characterized by an association of features that is observed in A. naduongensis, including a small size relative to most of other anthracotheriids, bunodont to bunoselenodont dentition, weak cingula, and a hypolophid on the lower molars. This specimen illustrates the precise morphology of m2-m3 of A. naduongensis from the type locality.