New material of the Early Pleistocene spiral horned antelope spirocerus (Artiodactyla, Mammalia) from North China and discussion on its evolution

The taxonomic and phylogenetic positions of spiral horned antelope Spirocerus have been controversial since its first discovery in Central Asia and with the discovery of more and more fossil specimens and localities in Central and East Asia. New material of Spirocerus wongi were recently identified from the fossil specimens collected from Nihewan Formation at Shuichongkou along Xinyaozi ravine of Tianzhen County, Shanxi Province in North China. Taxonomic study shows that three species of Spirocerus can be regarded valid, i.e. S kiakhtensis, S. wongi and S. peii. Phylogenetic analyses indicates that they form a distinct clade closer to Bovinae than to Antilopinae, and Spirocerus can be placed in Bovinae rather than in Antilopinae. S. kiakhtensis might evolve from a Gazellospira-like form migrated from Europe to Central Asia in the Pliocene, then dispersed into northern China in the Early Pleistocene and evolved into S. wongi and S. peii. S. wongi dispersed further into northwestern and central China in the Early Pleistocene and disappeared in the Middle Pleistocene. S. peii ranged only in northern China in the Middle Pleistocene. After dispersion into northwestern and northeastern China in the Late Pleistocene, S. kiakhtensis disappeared near the end of the Pleistocene.