Chasmosaurus

***Chasmosaurus*** (/ˌkæzmoʊˈsɔːrəs/ *KAZ-mo-SAWR-əs*) is a genus of ceratopsid dinosaur from the Upper Cretaceous Period of North America. Its name means 'opening lizard', referring to the large openings (fenestrae) in its frill (Greek *chasma* meaning 'opening' or 'hollow' or 'gulf' and *sauros* meaning 'lizard'). With a length of 4.3–4.8 metres (14.1–15.7 ft) and a weight of 1.5–2 tonnes (1.7–2.2 short tons), *Chasmosaurus* was a ceratopsian of average size. Like all ceratopsians, it was purely herbivorous. It was initially to be called *Protorosaurus*, but this name had been previously published for another animal. All specimens of *Chasmosaurus* were collected from the Dinosaur Park Formation of the Dinosaur Provincial Park of Alberta, Canada. *C. russelli* comes from the lower beds of the formation while *C. belli* comes from middle and upper beds. *Chasmosaurus* was a medium-size ceratopsid. In 2010 G.S. Paul estimated the length of *C. belli* at 4.8 metres, its weight at two tonnes; *C. russelli* would have been 4.3 metres long and weighed 1.5 tonnes.[2] The known differences between the two species mainly pertain to the horn and frill shape, as the postcrania of *C. russelli* are poorly known. Like many ceratopsians, *Chasmosaurus* had three main facial horns - one on the nose and two on the brow. In both species these horns are quite short, but with *C. russelli* they are somewhat longer, especially the brow horns, and more curved backwards. The frill of *Chasmosaurus* is very elongated and broader at the rear than at the front. It is hardly elevated from the plane of the snout. With *C. belli* the rear of the frill is V-shaped and its sides are straight. With *C. russelli* the rear edge is shaped as a shallow U, and the sides are more convex.[2] The sides were adorned by six to nine smaller skin ossifications (called episquamosals) or osteoderms, which attached to the squamosal bone. The corner of the frill featured two larger osteoderms on the parietal bone. With *C. russelli* the outer one was the largest, with *C. belli* the inner one. The remainder of the rear edge lacked osteoderms. The parietal bones of the frill were pierced by very large openings, after which the genus was named: the parietal fenestrae. These were not oval in shape, as with most relatives, but triangular, with one point orientated towards the frill corner.

The postcranium of *C. belli* is best preserved in the specimen known as NHMUK 4948. The first three cervical vertebrae are fused into a unit known as a syncervical, as in other neoceratopsians. There are five other cervicals preserved in this specimen, for a total of eight, which likely represents a complete neck. Cervicals four to eight are amphiplatian, wider than long, and roughly equal in length. The dorsal vertebrae are also amphiplatian. *C. belli* possessed a synsacrum, a compound unit composed of sacral, dorsal, and sometimes caudal vertebrae, depending on the specimen.

The *Chasmosaurus* specimen NMC 2245 recovered by C.M. Sternberg was accompanied by skin impressions.[4] The area conserved, from the right hip region, measured about one by 0.5 metres. The skin appears to have had large scales in evenly spaced horizontal rows among smaller scales.[4] The larger scales had a diameter of up to fifty-five millimetres and were distanced from each other by five to ten centimetres. They were hexagonal or pentagonal, thus with five or six sides. Each of these sides touched somewhat smaller scales, forming a rosette. Small, non-overlapping convex scales of about one centimetre in diameter surrounded the whole. The larger scales were wrinkled due to straight grooves orientated perpendicular to their edges. From top to bottom, the large scale rows gradually declined in size.[5] Unfortunately, nothing can as yet be learned about the coloration of *Chasmosaurus* from the known fossil skin impression samples.

one species is a brown varient with a dark yellow underbelly with red colors in the frill

another is a peach varient with darker coloration on the head and blue colors in the frill
the last is a green species and black stripes from tail to back legs and on the frill with orange colors on the frill