NEW MULTITUBERCULATE MAMMALS FROM THE LOWER CRETACEOUS (SHAHAI AND FUXIN FORMATIONS), NORTHEASTERN CHINA

Two eobaatarid multituberculates, Heishanobaatar triangulus gen. et sp. nov. and Eobaataridae gen. et sp. indet., and an ?albionbaatarid multituberculate, Kielanobaatar badaohaoensis gen. et sp. nov., from the Lower Cretaceous (Aptian to Albian) Shahai and Fuxin formations in Liaoning Province, northeastern China, are described. Heishanobaatar triangulus is a moderate-sized multituberculate characterized by lower jaw dental formula 1.0.3.2, slender lower incisor, single-rooted p2, triangular p3 in lateral view, p4 with eight serrations, m1 with cusp formula 2:2, and m2 with cusp formula 1 (coalesced):2. Kielanobaatar badaohaoensis is characterized by upper anterior premolars with relatively flat occlusal surfaces, roughly pentangular P1 in occlusal view, P1 and P2 with three cusp rows (cusp formulae 1:3:2), and P3 with four cusps (cusp formula 2:2). Together with already described three species of eobaatarids from the same localities, they demonstrate that there were quite diverse multituberculates in Asia in the late Early Cretaceous, and suggest that the mammalian fauna known from the Shahai and Fuxin formations probably show a transitional state from the mammalian fauna of the Yixian Formation to Late Cretaceous Asian faunas.