Montanoceratops cerorhynchus (Dinosauria: Ceratopsia) and relationships among basal neoceratopsians

Montanoceratops cerorhynchus has been described as the sister group of Ceratopsidae, even though analyses and diagnosis of this taxon have been tentative and incomplete. A second specimen of M. cerorhynchus includes new diagnostic elements, most notably a partial skull including the caudal half of the braincase, pectoral girdle and manus. Results of a cladistic analysis of eight basal neoceratopsians (Protoceratops, Leptoceratops, Bagaceratops, Microceratops, Breviceratops, Montanoceratops, Asiaceratops, and Udanoceratops) and four ceratopsids (Centrosaurus, Anchiceratops, Chasmosaurus, and Styracosaurus) confirm Montanoceratops as the sister group of Ceratopsidae. Microceratops and Asiaceratops are positioned at the base of Neoceratopsia. Protoceratops, Leptoceratops, and Udanoceratops constitute a monophyletic Protoceratopsidae. Paleogeographical interpretation of the cladogram suggests that Neoceratopsia originated in Asia, and that there were at least two migrations of ceratopsians from Asia to North America.