Leptoceratops

Leptoceratops (meaning 'small horn face') is a genus of ceratopsian dinosaur from the Late Cretaceous of North America. First found in Alberta in 1910, the type species Leptoceratops gracilis was named in 1914 by Barnum Brown for a partial skull and skeleton of two individuals found in the Scollard Formation of Alberta. Additional specimens found in the Scollard include one complete and two mostly complete skeletons together, uncovered in 1947 by Charles M. Sternberg. Specimens from Montana that were among the earliest referred to Leptoceratops have since been moved to their own genera Montanoceratops and Cerasinops, while new specimens of L. gracilis include bonebed remains from the Hell Creek Formation of Montana and a partial skeleton from the Lance Formation of Wyoming. Together with related taxa, Leptoceratops is the eponymous genus of the family Leptoceratopsidae. Leptoceratops is known from more than ten individuals, all from Maastrichtian deposits of Alberta, Montana and Wyoming, representing the entire skeleton.

Multiple unusual features can be seen in the skeleton of Leptoceratops, which has a mixture of primitive and derived ceratopsian features and is around long. The head is very large with a strong jaw, but lacks horns and has a very reduced frill. The forelimbs and hindlimbs are robustly built, and Leptoceratops was likely bipedal when moving at speed and quadrupedal when moving slowly. The vertebrae of the tail were high-spined, though not as high as those of its relative Montanoceratops, and the pectoral and pelvis girdle bones were slender and more like earlier ceratopsians. The teeth of Leptoceratops are unique among dinosaurs, showing tooth wear in a fashion that must have been driven by mammal-like rotation of the jaw while chewing. This, along with the handling of stress in the jaws, show that Leptoceratops had an efficient bite allowing it to be adaptable to different food types, such as the angiosperms, conifers, or cycads found in its environment.