Chasmosaurus

Chasmosaurus (/ˌkæzmoʊˈsɔːrəs/ KAZ-moh-SOR-əs) is a genus of ceratopsid dinosaur from the Late Cretaceous Period in North America. Its given name means 'opening lizard', referring to the large openings (fenestrae) in its frill (Greek chasma, meaning 'opening', '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)—or anywhere from 2,200 to nearly 5,000 lbs., give or take—Chasmosaurus was of a slightly smaller to ‘average’ size, especially when compared to larger ceratopsians (such as Triceratops, which were about the size of an African bush elephant). The Chasmosaurs were similar, in overall build and weight, to a white rhinoceros or an Indian rhinoceros; just like rhinos, and all other ceratopsians, they were purely herbivorous, needing to consume around 54 kilograms, or 120 lbs., of plant matter each day.

It was initially to be called Protorosaurus, but this name had been previously published for another animal. All of the excavated specimens of Chasmosaurus were collected at the Dinosaur Park Formation, Dinosaur Provincial Park, Alberta, Canada. Referred specimens of C. russelli come from the lower beds of the formation, while C. belli comes from the middle and upper beds.