Chasmosaurus 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. With a length of 4.3–4.8 metres (14.1–15.7 ft) and a weight of 1.5–2 tonnes —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. 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.
Ceratopsidae is a family of ceratopsian dinosaurs including Triceratops, Centrosaurus, and Styracosaurus. All known species were quadrupedal herbivores from the Upper Cretaceous. All but one species are known from western North America, which formed the island continent of Laramidia during most of the Late Cretaceous. Ceratopsids are characterized by beaks, rows of shearing teeth in the back of the jaw, elaborate nasal horns, and a thin parietal-squamosal shelf that extends back and up into a frill. The group is divided into two subfamilies—Chasmosaurinae and Centrosaurinae. The chasmosaurines are generally characterized by long, triangular frills and well-developed brow horns. The centrosaurines had well-developed nasal horns or nasal bosses, shorter and more rectangular frills, and elaborate spines on the back of the frill.
Styracosaurus is a genus of herbivorous ceratopsian dinosaur from the Cretaceous Period, about 75.5 to 74.5 million years ago. It had four to six long parietal spikes extending from its neck frill, a smaller jugal horn on each of its cheeks, and a single horn protruding from its nose, which may have been up to 60 centimeters long and 15 centimeters wide. The function or functions of the horns and frills have been debated for many years.
Achelousaurus is a genus of centrosaurine ceratopsid dinosaur that lived during the Late Cretaceous Period of what is now North America, about 74.2 million years ago. The first fossils of Achelousaurus were collected in Montana in 1987, by a team led by Jack Horner, with more finds made in 1989. In 1994, Achelousaurus horneri was described and named by Scott D. Sampson; the generic name means "Achelous lizard", in reference to the Greek deity Achelous, and the specific name refers to Horner. The genus is known from a few specimens consisting mainly of skull material from individuals, ranging from juveniles to adults.
Anchiceratops is an extinct genus of chasmosaurine ceratopsid dinosaur that lived approximately 72 to 71 million years ago during the latter part of the Cretaceous Period in what is now Alberta, Canada. Anchiceratops was a medium-sized, heavily built, ground-dwelling, quadrupedal herbivore that could grow up to an estimated 4.3 metres (14 ft) long. Its skull featured two long brow horns and a short horn on the nose. The skull frill was elongated and rectangular, its edges adorned by coarse triangular projections. About a dozen skulls of the genus have been found.
Avaceratops is a genus of small herbivorous ceratopsian dinosaurs which lived during the late Campanian during the Late Cretaceous Period in what are now the Northwest United States. Most fossils come from the Judith River Formation.
Medusaceratops is an extinct genus of centrosaurine ceratopsian dinosaur known from the Late Cretaceous Judith River Formation of Montana, northern United States. It contains a single species, Medusaceratops lokii.
Albertaceratops was a genus of centrosaurine horned dinosaur from the middle Campanian-age Upper Cretaceous Oldman Formation of Alberta, Canada.
Centrosaurinae is a subfamily of ceratopsid, a group of large quadrupedal ornithischian dinosaur. Centrosaurine fossil remains are known primarily from the northern region of Laramidia but isolated taxa have been found in China and Utah as well.
Sinoceratops is an extinct genus of ceratopsian dinosaur that lived approximately 73 million years ago during the latter part of the Cretaceous Period in what is now Shandong province in China. It was named in 2010 by Xu Xing et al. for three skulls from Zhucheng, China. The name of its type species Sinoceratops zhuchengensis means "Chinese horned face from Zhucheng", after the location of its discovery.
Kosmoceratops is a genus of ceratopsid dinosaur that lived in North America about 76–75.9 million years ago during the Late Cretaceous period. Specimens were discovered in Utah in the Kaiparowits Formation of the Grand Staircase–Escalante National Monument in 2006 and 2007, including an adult skull and postcranial skeleton and partial subadults. In 2010, the adult was made the holotype of the new genus and species Kosmoceratops richardsoni; the generic name means "ornate horned face", and the specific name honors Scott Richardson, who found the specimens. The find was part of a spate of ceratopsian discoveries in the early 21st century, and Kosmoceratops was considered significant due to its elaborate skull ornamentation.
Nasutoceratops is an extinct genus of ceratopsian dinosaur. It is a basal centrosaurine which lived during the Late Cretaceous Period. 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.
Xenoceratops is a genus of centrosaurine ceratopsid dinosaur known from the Late Cretaceous, and is known to have lived in what is currently Alberta, Canada. The genus has one known species, Xenoceratops foremostensis. Its remains were discovered in the Foremost Formation.
Coronosaurus is a genus of centrosaurine ceratopsian dinosaurs which lived in the Late Cretaceous, in the middle Campanian stage. Its remains, two bone beds, were discovered by Phillip J. Currie in the Oldman Formation of Alberta, Canada, and its type and only species, Coronosaurus brinkmani, was first described in 2005, as a new species within the genus Centrosaurus. Later studies questioned the presence of a direct relationship, and in 2012 it was named as a separate genus. Coronosaurus means "crowned lizard", coming from "corona", Latin for crown, and "sauros", Greek for lizard; this name refers to the unique, crown-like shape of the horns on the top of its frill.
Judiceratops is an extinct horned dinosaur. It lived around 78 million years ago, during the Late Cretaceous Period in what is now Montana, United States. Like other horned dinosaurs, Judiceratops was a large, quadrupedal herbivore. It is the oldest known chasmosaurine.
Regaliceratops is a monospecific genus of chasmosaurine ceratopsid dinosaur from Alberta, Canada that lived during the Late Cretaceous in what is now the St. Mary River Formation. The type and only species, Regaliceratops peterhewsi, is known only from an adult individual with a nearly complete skull lacking the lower jaw, which was nicknamed "Hellboy". Regaliceratops was named in 2015 by Caleb M. Brown and Donald M. Henderson. Regaliceratops has an estimated length of 5 metres (16 ft) and body mass of 2 metric tons. The skull of Regaliceratops displays features more similar to centrosaurines, which suggests convergent evolution in display morphology in ceratopsids.
Wendiceratops is a genus of herbivorous centrosaurine ceratopsian dinosaur from the Late Cretaceous of Canada.
Machairoceratops, previously known as the "Wahweap centrosaurine B", is an extinct genus of centrosaurine ceratopsian dinosaur known from the Late Cretaceous Wahweap Formation of Grand Staircase–Escalante National Monument, southern Utah, United States.
Spiclypeus is an extinct genus of chasmosaurine ceratopsian dinosaur known from the Late Cretaceous Judith River Formation of Montana, United States.
Yehuecauhceratops is a genus of horned centrosaurine ceratopsid dinosaur from the Late Cretaceous of Coahuila, Mexico. It contains a single species, Y. mudei, described from two partial specimens by Rivera-Sylva et al. in 2016 and formally named by Rivera-Sylva et al. in 2017. It was a small centrosaurine with a body length of 3 metres (9.8 ft), making it smaller than Agujaceratops and Coahuilaceratops, the other two ceratopsids in its environment; the three may have been ecologically segregated. A ridge bearing a single roughened projection near the bottom of the squamosal bone, which probably supported a small horn, allows Yehuecauhceratops to be distinguished from other centrosaurines. Its affinities to nasutoceratopsin centrosaurines, such as Avaceratops and Nasutoceratops, are supported by various morphological similarities to the former.
