A horned dinosaur from the El Picacho formation of west Texas, and review of Ceratopsian dinosaurs from the American southwest

Fragmentary remains of a long-frilled ceratopsian dinosaur from the El Picacho Formation (Maastrichtian) of West Texas pertain to an undescribed form. The remains are, however, insufficient to fully characterize this species. This ceratopsian has long thick squamosals with marginal undulations, nasals lacking a discrete horncore, a thin parietal, and large trihedral epijugals. The braincase has very thick lateral walls, and a well- developed postfrontal foramen. Four species of horned dinosaurs are known from Upper Cretaceous strata of the American Southwest: Pentaceratops sternbergii, Chasmosaurus mariscalensis, Torosaurus utahensis, and the El Picacho ceratopsian. All of these belong to the subfamily Chasmosaurinae.