The first confirmation of North American extinct shrub-ox (Euceratherium, Artiodactyla, Mammalia) in the Early Pleistocene of northern China

Euceratherium is a genus generally considered to represent an Ovibovine member of the Caprini, and up to date considered to occur only in North America. Here, we describe two species of Euceratherium discovered from the Early Pleistocene deposits in northern China, E. collinum and Euceratherium sp., the first confirmed record of Euceratherium in Eurasia and outside North America. The earlier age of Chinese Euceratherium than that of its North American counterpart indicates that Euceratherium might originate from East Asia and spread into North America later. The phylogenetic analysis based on the North American and our Euceratherium collinum materials indicates its closer relationship to Ovibos moschatus than the other bovids. Ecomorphological analysis based on the teeth and metapodials of Euceratherium sp. from Xinyaozi suggests that the Chinese species has the same paleodiet and paleohabitat preferences as those of its North American counterpart. By broadening our study from Euceratherium to its upper taxonomic group, the Quaternary Ovibovine, we found that the latter probably originated from a Kabulicornis-like form and could be divided into two groups in the Late Pliocene, “alticornis” and “depressicornis”. These two groups evolved in Eurasia in the Early Pleistocene. They might disperse from Eurasia to North America twice, in the late Early Pleistocene and the late Middle Pleistocene, respectively.