New early ruminants (Mammalia: Artiodactyla) from the Oligocene of Nei Mongol (China), with remarks on their phylogenetic relationship

Ruminants were widely distributed throughout Eurasia and North America from the Eocene to the Oligocene. However, their systematics and early evolution remain obscure. Here, we describe new ruminant specimens collected from late Early Oligocene strata in Nei Mongol, China, identified as Paragelocus cf. scotti and new species of Praetragulus and Gobiomeryx. The two new species are the last representatives of their respective genera. We ran a cladistic analysis based on 52 dental and postcranial characters of 30 species. Praetragulus is found to be closely related to the North American ruminants Leptomeryx and Hypertragulus. Paragelocus, characterized by a distinct longitudinal lingual cristid on p4, is recovered as a sister taxon to Pseudomeryx, forming a monophyletic group with Gobiomeryx and Pseudogelocus. Including the additional Lophiomeryx fossils recently reported, the Saint Jacques–Qianlishan area has now yielded four genera (seven species) of stem ruminants representing three lineages, suggesting a flourishing and complex evolutionary history of early ruminants in Asia during the Oligocene. https://zoobank.org/urn:lsid:zoobank.org:pub:6409D5F3-BA93-4BE6-8100-70C575C9FC14