Description of Prenoceratops pieganensis gen. et sp. nov. (Dinosauria: Neoceratopsia) from the Two Medicine Formation of Montana

ABSTRACT

A new basal neoceratopsian genus and species, Prenoceratops pieganensis, is described from the Two Medicine Formation of Montana. This material represents the only bone-bed deposition of a basal neoceratopsian currently known, and in addition is almost entirely disarticulated allowing for a more thorough understanding of basal neoceratopsian cranial morphology. The new taxon is characterized by a lower, more sloping head than in Leptoceratops, with a nasal that is pinched caudally, a wide, triangular jugal, extremely gracile surangular, and reduced articular among other autapomorphies. A preliminary cladistic analysis unites Prenoceratops firmly with the other North American basal neoceratopsians (and one Asian taxon) in the clade Leptoceratopsidae.