[D] Archaeoceratops oshimai [Su] [sG] [T]
Dong & Azuma, 1997
Ornithischia Genasauria Cerapoda Marginocephalia Ceratopia Neoceratopia Archaeoceratopidae
Xinminbao Group, Gongpoquan Basin of the Mazongshan Area, Gansu Province, China
Archaeoceratops oshimai (Dong & Azuma, 1997) > Archaeoceratops yujingziensis (You, Tanque & Dodson 2010)
Genus - Typespecies - Skull
Holotype: IVPP V11114 and a second skeleton V11115.
This is a spectacular specimen, known from two partial relatively small skeletons that include a skull with lower jaws, of a very primitive protoceratopid, apparently bipedal. Premaxillary teeth are present. The frill is relatively short, but the skull is quite large compared to body size.
It seems closest to Microceratops in overall appearance. Dong Zhiming & Yoichi Azuma, 1997. \\\\\\\"On a Primitive Neoceratopsian from the Early Cretaceous of China,\\\\\\\" in Dong Z., ed., 1997: 68-89. Features new genus and species Archaeoceratops oshimai Dong & Azuma, 1997, in new family [Archaeoceratopsidae - Archaeoceratopidae] Dong & Azuma, 1997 at the base of Neoceratopsia, including besides the nominal genus the genera Microceratops and Kulceratops. Archaeoceratops is clearly more advanced than Chaoyangsaurus
You, Hai-lu and Dodson, Peter. 2003. Redescription of neoceratopsian dinosaur Archaeoceratops and early evolution of Neoceratopsia. Acta Geologica Polonica 48(2): 261-272.
Archaeoceratops oshimai Dong and Azuma, 1997 is a basal neoceratopsian from the late Early Cretaceous of Mazongshan area, Gansu Province, northwest China. Here we provide a detailed description on Archaeoceratops oshimai based on both the holotype, which consists of a well preserved, nearly complete skull, partial vertebral column, and partial pelvis, and the paratype, which consists of a partial vertebral column including a nearly complete tail, a partial pelvis, fragmentary hind limb bones, and a complete pes.
Cladistic analysis shows that Archaeoceratops is the sister group to all currently known Late Cretaceous Neoceratopsia, and Late Cretaceous Neoceratopsia diverged into two clades: the Asian Protoceratopidae and the North American Ceratopidae, indicating a dual evolution for the two major groups of horned dinosaurs in two landmasses of Late Cretaceous. A suite of derived features characterizes Ceratopsoidea, such as a round-shaped external naris, a long caudolateral process of the rostral bone, and ventrally curved premaxillary ventral edge.