Sampson's words, "the buffalo of the Cretaceous", living in herds and having a complex life. According to Sampson, the name should be pronounced as "eye-knee-o-saurus". The specific name is derived from Latin procurvus, "bent forwards", and cornu, "horn", referring to the forwards curving nasal horn. The holotype, MOR 456-8-9-6-1, was found in a layer of the Two Medicine Formation dating from the late Campanian. It consists of a partial skull, including the nasal horn, the supraorbital area and part of the parietal bone of the skull frill. The skull represents an adult individual. Sampson referred many other specimens to the species. He indicated that additional fossil material from the Canyon Bone Bed had been subsumed under the inventory number MOR 456. This included two further adult skulls and single cranial and postcranial bones from individuals of varying age classes. Furthermore, the fossils from the Dino Ridge Quarry were referred. They had been catalogued within number MOR 373. They consisted of about two hundred non-articulated bones, again from animals of different ages. In 2010, Paul renamed E. procurvicornis into Centrosaurus procurvicornis, but this has found no acceptance, subsequent research invariably referring to the taxon as Einiosaurus. Description Size and distinguishing traits Einiosaurus was a herbivorous dinosaur. It is generally as large as Achelousaurus, though far less robust. In 2010, Gregory S. Paul estimated the body length of Einiosaurus at , its weight at . Both taxa fall within the typical size range of the Centrosaurinae. In 1995, Sampson indicated several distinguishing traits. The nasal horn has a base that is long from front to rear, is transversely flattened, and is strongly curved forwards in some adult specimens. The supraorbital "brow" horns as far as they are present are low and rounded with a convex surface on the inner side. The parietal parts of the rear edge of the skull frill together bear a single pair of large curved spikes sticking out to behind. Einiosaurus differs from all other known Centrosaurinae by a longer-based and more procurved nasal horn and by a supraorbital horn that is longer-based and more rounded in side view. It differs from Achelousaurus in particular in having large parietal spikes that are not directed sideways to some extent. As a centrosaurine, Einiosaurus walked on all fours, had a large head with a beak, a moderately large skull frill, a short powerful neck, heavily muscled forelimbs, a high torso,