The first complete cranium of Homotherium (Machairodontinae, Felidae) from the Nihewan Basin (northern China)

The Nihewan Basin is famous for producing a rich Early Pleistocene fauna, the most classic and standard for the Early Pleistocene of northern China, as well as rich paleolithic remains, documenting the early presence of humans. Many fossil Carnivora, including the scimitar toothed cat Homotherium, were found from this basin, but no complete material of this cat was known, which hampers a deep study of its taxonomy. Here, we report a complete cranium of Homotherium, found in Shigou, a recently discovered locality in the Nihewan Basin. The morphology of the cranium supports its assignment to Homotherium crenatidens teilhardipiveteaui, a terminal evolutionary stage of the species with a Palearctic distribution. Our analyses suggest that Homotherium evolved largely contemporarily in different regions of Eurasia, suggesting a continuous gene flow within the continent, and the subspecies delimitation should be more chronological than geographical.