New skull of Megantereon inexpectatus (Carnivora: Machairodontinae) and its implications on evolution of Megantereon in North China

Megantereon is an iconic sabertoothed cat known from the Quaternary deposits of the Old World, being its evolutionary scenario and phylogenetic relationships hotly debated the last decades. Several authors proposed that there is only one species, i.e. M. cultridens , or two species, plus M. whitei in Eurasia and Africa of Pleistocene, while some authors proposed multiple species present. Here we describe a mostly complete cranium and several fragmented mandibular fragments of a very large and robust form of Megantereon from Bajiazui, Qingyang, northwestern China, assigned to M. inexpectatus . Several new skulls/crania of M. nihowanensis from Longdan (Gansu, China) were analysed and they further provide a better basis for evaluating the intraspecific variability of this lineage. The analyses here reported, support the recognition of two species from a single lineage of Megantereon in northern China since the earliest Pleistocene to the middle Pleistocene, with smaller M. nihowanensis in the Gelasian, and slightly larger and more robust M. inexpectatus with more derived dentition during the Calabrian to the early Middle Pleistocene. This scenario is different from what is seen in Europe, where the primitive M. cultridens evolved to smaller and dentally specialized M. adroveri .