Nasutoceratops

Nasutoceratops is an extinct genus of ceratopsian dinosaur . It is a basal centrosaurine which lived during the late Cretaceous period (late Campanian, about 76.0-75.5 Ma). Fossils have been found in southern Utah, United States. Nasutoceratops was a large, ground-dwelling, quadrupedal herbivore with a short snout and unique rounded horns above its eyes that have been likened to those of modern cattle. Extending almost to the tip of its snout, these horns are the longest of all the members of the centrosaurine subfamily. The presence of pneumatic elements in the nasal bones of Nasutoceratops are a unique trait and are unknown in any other ceratopsid. Nasutoceratops, Diabloceratops , and Machairoceratops are the only three centrosaurine dinosaurs from the American southwest.
The holotype skull is approximately 1.5 metres (4.9 ft) in length. Its body length has been estimated at 4.5 metres (14.8 ft), its weight at 1.5 tonnes (1.7 short tons).[5] Nasutoceratops has several unique derived traits or autapomorphies. The part of the snout around the nostril is strongly developed, representing about three quarters of the skull length in front of the eye sockets. The rear of each nasal bone is hollowed out by a large internal cavity. The contact surface between the maxilla and the praemaxilla is exceptionally large. The maxilla also has a large internal flange contacting the praemaxilla via two horizontal facets. The brow horns at their bases are pointed forwards and outwards, then curve inwards, and ultimately twist their points upwards.[4]

Nasutoceratops also shows a unique combination of traits that are in themselves not unique. The horn on the nose is low and narrow, with an elongated base. The squamosal has a high ridge on its upper surface, running from the direction of the eye socket towards the squamosal rim. The skull frill is more or less circular with its widest point at the middle edge. The osteoderms on the frill edge, the epiparietals and episquamosals, do not have the form of spikes but are shaped like simple low crescents. The rear frill edge is not notched but instead has an epiparietal on the midline.[4]

Skull diagram
The snout of Nasutoceratops was short and high; its nasal bones exhibit internal cavities that the authors consider to represent pneumatic excavations, invading the bone from the nasal cavity. This is noteworthy because pneumatic nasals are unknown in any other ceratopsid, which supports that this feature represents a unique derived trait of this genus. Nasutoceratops had as many as 29 tooth positions in the maxilla, each occupied by several stacked teeth. The skull roof between the eye sockets is vaulted and is markedly higher than the snout region. The curved horizontally projecting brow horn arrangement was likened to that of modern cattle by paleontologist David Hone.[6] The brow horns span approximately 40% of the total length of the skull, almost reaching the level of the snout tip, and with a bone core length of up to 457 millimetres are the longest known of any centrosaurine, both in absolute and relative terms.[3]

The epijugal (cheek horn) has a length of 85 millimetres (3.3 in), also the largest known among centrosaurines. The skull frill is moderately long, and pierced by a large kidney-shaped parietal fenestra at each side. Apart from the midline epiparietal, there are seven epiparietals at each side, and about four to five episquamosals.[3] In the forelimb, the ulna is exceptionally robust with a large olecranon process. Of the three patches with skin impressions found near the left shoulder, one shows a pattern of large, eight to eleven millimetres wide, hexagonal scales surrounded by smaller triangular scales.

   the only known species of Nasutoceratops is a grey variant with red coloring on the frill