Kosmoceratops
Encyclopedia
Kosmoceratops is a genus
of herbivorous chasmosaurine
ceratopsia
n dinosaur
, which lived during the Late Cretaceous
period (late Campanian
) in the part of the island continent Laramidia
that is now Utah
, United States
. Its fossils have been recovered from the Kaiparowits Formation
in the Grand Staircase-Escalante National Monument
. It was first named by Scott D. Sampson
, Mark A. Loewen, Andrew A. Farke, Eric M. Roberts, Catherine A. Forster, Joshua A. Smith, and Alan L. Titus in 2010
along with the chasmosaurine genera Utahceratops
(also from the monument) and Vagaceratops
(from Alberta
). The type species
is K. richardsoni, named in honor of Scott Richardson, a volunteer who discovered the holotype
specimen and many other fossils within the Grand Staircase-Escalante National Monument.
in front of the eye sockets. The nasal horncore, the bony projection from which the nose horn grew, is flattened and blade-like. The frill
of Kosmoceratops is the shortest relative to its width of any ceratopsian; it is about twice as wide as it is long. The parietal fenestrae, two holes in the frill, are also very small and are positioned toward the back. The size of the frill and its fenestrae differ considerably from other chasmosaurines, many of which are known for their elongate frills. Ten hook-like projections rim the frill. Eight of these hooks curve forward to overlie the frill, while the other two are positioned on either side of it, curving laterally rather than rostrally. Overall, there are fifteen horns or horn-like structures on the skull, the most of any ceratopsian.
from Sampson et al. (2010):
, an island continent at the time that now forms western North America
. During the Late Cretaceous, Laramidia was separated from Appalachia
, the eastern North American landmass, by the Western Interior Seaway
. A major evolutionary radiation
took place on Laramidia, with many major dinosaur clade
s known from across the island continent. Two endemic faunas may have existed in separate biome
s or "provinces": one to the south of what is now Utah and Colorado
, and one north of this region. Kosmoceratops, along with most other Campanian chasmosaurines, lived in the southern province, while the north was only inhabited by species of Chasmosaurus
that existed in what is now Alberta.
Chasmosaurines appear to have originated in Laramidia around 80-90 Ma, and dispersed throughout the continent by 77 Ma. By this time, a barrier had appeared in the area of Utah and Colorado that separated the two provinces. Kosmoceratops appeared in the southern province after the barrier appeared. Then, with the dissolution of the barrier around 75.7 Ma, the Kosmoceratops lineage migrated northward. In the northern province, forms such as Vagaceratops
appeared. These forms would later give rise to the more derived
chasmosaurines of the late Campanian and Maastrichtian
stages, including Anchiceratops
, Arrhinoceratops
, Nedoceratops, and Triceratops
.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of herbivorous chasmosaurine
Chasmosaurinae
Chasmosaurinae is a subfamily of ceratopsid dinosaurs. Triceratops is a well-known example. They were one of the most successful groups of herbivores of their time. Chasmosaurines appeared in the early Campanian, and became extinct, along with all other non-avian dinosaurs, during the K-T extinction...
ceratopsia
Ceratopsia
Ceratopsia or Ceratopia is a group of herbivorous, beaked dinosaurs which thrived in what are now North America, Europe, and Asia, during the Cretaceous Period, although ancestral forms lived earlier, in the Jurassic. The earliest known ceratopsian, Yinlong downsi, lived between 161.2 and 155.7...
n dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
, which lived during the Late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
period (late Campanian
Campanian
The Campanian is, in the ICS' geologic timescale, the fifth of six ages of the Late Cretaceous epoch . The Campanian spans the time from 83.5 ± 0.7 Ma to 70.6 ± 0.6 Ma ...
) in the part of the island continent Laramidia
Laramidia
Laramidia is a name coined by J. David Archibald in 1996 to describe an island continent that existed during the Late Cretaceous period, when the Western Interior Seaway split the continent of North America in two. Two landmasses existed: the eastern one is called Appalachia; Laramidia is the name...
that is now Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...
, United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. Its fossils have been recovered from the Kaiparowits Formation
Kaiparowits Formation
The Kaiparowits Formation is a sedimentary rock formation found in the Kaiparowits Plateau in Grand Staircase-Escalante National Monument, in the southern part of Utah in the western United States. It is over 2800 feet thick, and is Campanian in age...
in the Grand Staircase-Escalante National Monument
Grand Staircase-Escalante National Monument
The Grand Staircase-Escalante National Monument contains 1.9 million acres of land in southern Utah, the United States. There are three main regions: the Grand Staircase, the Kaiparowits Plateau, and the Canyons of the Escalante. President Bill Clinton designated the area as a U.S. National...
. It was first named by Scott D. Sampson
Scott D. Sampson
Scott D. Sampson is a paleontologist and chief curator of the Utah Museum of Natural History. Sampson is notable for his work on the carnivorous theropod dinosaurs Majungasaurus and Masiakasaurus and his extensive research into the Late Cretaceous Period, particularly in...
, Mark A. Loewen, Andrew A. Farke, Eric M. Roberts, Catherine A. Forster, Joshua A. Smith, and Alan L. Titus in 2010
2010 in paleontology
-Anomalocaridids:-Newly named crustaceans:-Newly named insects:* A new family, Cascopleciidae, is published by Poinar Jr.* A new family of ceraphronoid Hymenopters, Radiophronidae, is published by Ortega-Blanco, Rasnitsyn, and Delclòs....
along with the chasmosaurine genera Utahceratops
Utahceratops
Utahceratops is a genus of herbivorous ceratopsian dinosaur. It is a chasmosaurine ceratopsian which lived during the Late Cretaceous period in what is now Utah. Its fossils have been recovered from the Kaiparowits Formation. It was first named by Scott D. Sampson, Mark A. Loewen, Andrew A....
(also from the monument) and Vagaceratops
Vagaceratops
Vagaceratops is a genus of herbivorous ceratopsian dinosaur. It is a chasmosaurine ceratopsian which lived during the Late Cretaceous period in what is now Alberta. Its fossils have been recovered from the Upper Dinosaur Park Formation...
(from Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
). The type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
is K. richardsoni, named in honor of Scott Richardson, a volunteer who discovered the holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
specimen and many other fossils within the Grand Staircase-Escalante National Monument.
Description
Kosmoceratops is distinguished by an ornate skull, the most ornate of any known dinosaur. The horns above the eyes are long, thin, and pointed. They project laterally from the skull and curve downward. The orientation of these horns differs from most other ceratopsians, in which the horns are oriented either forward, or backward. There is a forehead-like hump on the skull roofSkull roof
The skull roof , or the roofing bones of the skull are a set of bones covering the brain, eyes and nostrils in bony fishes and all land living vertebrates. The bones are derived from dermal bone, hence the alternative name dermatocranium...
in front of the eye sockets. The nasal horncore, the bony projection from which the nose horn grew, is flattened and blade-like. The frill
Neck frill
Neck frill is the popular term for the relatively extensive margin seen on the back of the heads of reptiles with either a bony support such as those present on the skulls of dinosaurs of the suborder Marginocephalia or a cartilaginous one as in the Frill-necked Lizard...
of Kosmoceratops is the shortest relative to its width of any ceratopsian; it is about twice as wide as it is long. The parietal fenestrae, two holes in the frill, are also very small and are positioned toward the back. The size of the frill and its fenestrae differ considerably from other chasmosaurines, many of which are known for their elongate frills. Ten hook-like projections rim the frill. Eight of these hooks curve forward to overlie the frill, while the other two are positioned on either side of it, curving laterally rather than rostrally. Overall, there are fifteen horns or horn-like structures on the skull, the most of any ceratopsian.
Phylogeny
Below is a cladogramCladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...
from Sampson et al. (2010):
Paleobiology
Kosmoceratops, along with most other chasmosaurines, inhabited LaramidiaLaramidia
Laramidia is a name coined by J. David Archibald in 1996 to describe an island continent that existed during the Late Cretaceous period, when the Western Interior Seaway split the continent of North America in two. Two landmasses existed: the eastern one is called Appalachia; Laramidia is the name...
, an island continent at the time that now forms western North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
. During the Late Cretaceous, Laramidia was separated from Appalachia
Appalachia (Mesozoic)
In the Mesozoic Era, Appalachia was a land area which is now an eastern part of the USA and Canada, separated from Laramidia by the Western Interior Seaway, which shrank, divided across the Dakotas, retreated south towards the Gulf of Mexico and finally dried up.-Fauna:From the Turonian age of the...
, the eastern North American landmass, by the Western Interior Seaway
Western Interior Seaway
The Western Interior Seaway, also called the Cretaceous Seaway, the Niobraran Sea, and the North American Inland Sea, was a huge inland sea that split the continent of North America into two halves, Laramidia and Appalachia, during most of the mid- and late-Cretaceous Period...
. A major evolutionary radiation
Evolutionary radiation
An evolutionary radiation is an increase in taxonomic diversity or morphological disparity, due to adaptive change or the opening of ecospace. Radiations may affect one clade or many, and be rapid or gradual; where they are rapid, and driven by a single lineage's adaptation to their environment,...
took place on Laramidia, with many major dinosaur clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
s known from across the island continent. Two endemic faunas may have existed in separate biome
Biome
Biomes are climatically and geographically defined as similar climatic conditions on the Earth, such as communities of plants, animals, and soil organisms, and are often referred to as ecosystems. Some parts of the earth have more or less the same kind of abiotic and biotic factors spread over a...
s or "provinces": one to the south of what is now Utah and Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
, and one north of this region. Kosmoceratops, along with most other Campanian chasmosaurines, lived in the southern province, while the north was only inhabited by species of Chasmosaurus
Chasmosaurus
Chasmosaurus is a genus of ceratopsid dinosaur from the Upper Cretaceous Period of North America. Its name means 'opening lizard', referring to the large openings in its frill . With a length of and a weight of , Chasmosaurus was a ceratopsian of average size...
that existed in what is now Alberta.
Chasmosaurines appear to have originated in Laramidia around 80-90 Ma, and dispersed throughout the continent by 77 Ma. By this time, a barrier had appeared in the area of Utah and Colorado that separated the two provinces. Kosmoceratops appeared in the southern province after the barrier appeared. Then, with the dissolution of the barrier around 75.7 Ma, the Kosmoceratops lineage migrated northward. In the northern province, forms such as Vagaceratops
Vagaceratops
Vagaceratops is a genus of herbivorous ceratopsian dinosaur. It is a chasmosaurine ceratopsian which lived during the Late Cretaceous period in what is now Alberta. Its fossils have been recovered from the Upper Dinosaur Park Formation...
appeared. These forms would later give rise to the more derived
Derived
In phylogenetics, a derived trait is a trait that is present in an organism, but was absent in the last common ancestor of the group being considered. This may also refer to structures that are not present in an organism, but were present in its ancestors, i.e. traits that have undergone secondary...
chasmosaurines of the late Campanian and Maastrichtian
Maastrichtian
The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...
stages, including Anchiceratops
Anchiceratops
Anchiceratops is a genus of chasmosaurine ceratopsid dinosaur from the Late Cretaceous Period of western North America. Like other ceratopsids, it was a quadrupedal herbivore with three horns on its face, a parrot-like beak, and a long frill extending from the back of its head. The two horns above...
, Arrhinoceratops
Arrhinoceratops
Arrhinoceratops is a genus of ceratopsian dinosaur. The name was coined as its original describer concluded it had no nose-horn, however further analysis revealed this not to be the case...
, Nedoceratops, and Triceratops
Triceratops
Triceratops is a genus of herbivorous ceratopsid dinosaur which lived during the late Maastrichtian stage of the Late Cretaceous Period, around 68 to 65 million years ago in what is now North America. It was one of the last dinosaur genera to appear before the great Cretaceous–Paleogene...
.