Xenoceratops Temporal range: Late Cretaceous, | |
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Reconstructed skull | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | † Ornithischia |
Clade: | † Neornithischia |
Clade: | † Ceratopsia |
Family: | † Ceratopsidae |
Subfamily: | † Centrosaurinae |
Genus: | † Xenoceratops Ryan, Evans & Shepherd, 2012 |
Type species | |
†Xenoceratops foremostensis Ryan, Evans & Shepherd, 2012 |
Xenoceratops (meaning "alien horned face") is a genus of centrosaurine ceratopsid dinosaur known from the Late Cretaceous (middle Campanian stage), 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. [1]
In 1958, Wann Langston, Jr. excavated skull fragments from the Foremost Formation near Foremost, Alberta. [2] The formation is very poorly understood in regards to dinosaur fauna; [1] aside from teeth, only hadrosaur skeletons and the pachycephalosaurid Colepiocephale have been reported. [1]
Langston stored the fragments in cabinets at the Canadian Museum of Nature in Ottawa. Around 2003, David C. Evans and Michael J. Ryan became curious about the specimens, and more thorough investigation was conducted in 2009. [2] They discovered it to be a new species and genus, and it was described in 2012 by Ryan, Evans, and Kieran M. Shepherd. At the time of discovery, Xenoceratops foremostensis was the oldest known taxon of ceratopsid dinosaur in Canada. It is also the first ceratopsian described from the Foremost Formation. Xenoceratops is named from the Greek xenos, meaning foreign or alien, and ceratops, meaning horned face. The combination is in reference to the lack of ceratopsian species known from the Foremost Formation. The specific epithet foremostensis is named after the town of Foremost, Alberta. [1]
Xenoceratops is based on CMN (Canadian Museum of Nature) 53282, a parietal. This is a skull bone that in ceratopsids makes up the medial (midline) and part of the lateral borders of the distinctive bony frill. Additional skull bones have also been assigned to the genus, including additional parietals, squamosals (bones which make up the rest of the frill's lateral borders), and a partial nasal. These bones appear to belong to at least three adult-sized individuals. Another fragmentary skull in the collections of the Royal Tyrrell Museum of Palaeontology is thought to belong to this genus as well. [1]
Xenoceratops can be distinguished from other ceratopsids by details of the frill's bony ornamentation. The two bony projections closest to the midline of the frill are thick knobs, oriented toward the midline. Next to each knob is a single long flattened straight spike pointing laterally and to the rear. The anterior corners of the parietal have a large triangular knob. Unlike most other centrosaurines, the midline bar of the frill has no bumps or other ornamentation. Xenoceratops probably had a nasal and brow horn configuration comparable to that of other basal centrosaurines. The holotype and associated skull material do not include much of the face, but the Royal Tyrrell skull shows evidence of large brow horns, perhaps similar to those of Albertaceratops and Diabloceratops . Similarly, the form of the nasal bone fragment suggests a long, low structure like that of Medusaceratops . [1]
The cladogram below follows a phylogenetic analysis by Chiba et al. (2017): [3]
Centrosaurinae |
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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.
Styracosaurus is an extinct genus of herbivorous ceratopsian dinosaur from the Late Cretaceous of North America. 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.
Centrosaurus is a genus of centrosaurine ceratopsian dinosaur from Campanian age of Late Cretaceous Canada. Their remains have been found in the Dinosaur Park Formation, dating from 76.5 to 75.5 million years ago.
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 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 from 73.5 to 66 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 genus of ceratopsid dinosaur that lived in North America during the Late Cretaceous period, about 76.0–75.5 million years ago. The first known specimens were discovered in Utah in the Kaiparowits Formation of the Grand Staircase–Escalante National Monument (GSENM) from 2006 onwards, including a subadult skull with a partial postcranial skeleton and rare skin impressions and two other partial skulls. In 2013, the subadult was made the holotype of the new genus and species Nasutoceratops titusi; the generic name means "large-nosed horned face", and the specific name honors the paleontologist Alan L. Titus for his work at the GSENM. The dinosaur was noted for its large nose in news reports, and later featured in Jurassic World films.
Spinops is an extinct genus of centrosaurine ceratopsian dinosaur from the Late Cretaceous of Alberta, southern Canada. It was a medium-sized ceratopsian, reaching 4.5 metres (15 ft) in length and 1.3 metric tons in body mass.
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.
Mercuriceratops is an extinct genus of herbivorous chasmosaurine ceratopsid dinosaur known from the Late Cretaceous of Alberta, Canada and Montana, United States. It contains a single species, Mercuriceratops gemini.
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.
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.