Arrhinoceratops
Encyclopedia
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. It lived during the earliest Maastrichtian
stage of the Late Cretaceous
, predating its famous relative Triceratops
by a few million years, although it was contemporary with Anchiceratops
. Its remains have been found in Canada
.
which lacked a lower jaw. The remains were collected from deposits of the Horseshoe Canyon Formation
, along the Red Deer River
in Alberta
by a 1923 expedition from the University of Toronto
.
Only one species is described, A. brachyops. Other material from Utah
, named by Gilmore in 1946, was originally known as A. utahensis, thence transferred to Torosaurus
.
-like beaks which thrived in North America
and Asia
during the Cretaceous Period, which ended roughly 65 million years ago. It appears to be closely related to Torosaurus
.
Since this dinosaur is known only from its skull, scientists know little about its over-all anatomy. The skull features a broad neck frill with two oval shaped openings. Its brow horns were moderately long, but its nose horn was shorter and blunter than most Ceratopsians. Its body is assumed to be typical of the Ceratopsians, and based on the skull it is estimated to be long when fully grown.
. During the Cretaceous, flowering plants were "geographically limited on the landscape", and so it is likely that this dinosaur fed on the predominant plants of the era: ferns, cycads and conifers. It would have used its sharp Ceratopsian beak to bite off the leaves or needles.
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 ceratopsian 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...
. The name was coined as its original describer concluded it had no nose-horn, however further analysis revealed this not to be the case. It lived during the earliest 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...
stage of the Late Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
, predating its famous relative 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...
by a few million years, although it was contemporary with 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...
. Its remains have been found in Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
.
Discoveries and species
Described by W. A. Parks in 1925, Arrhinoceratops is known from a partially crushed, slightly distorted skullSkull
The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...
which lacked a lower jaw. The remains were collected from deposits of the Horseshoe Canyon Formation
Horseshoe Canyon Formation
The Horseshoe Canyon Formation is part of the Edmonton Group and is up to 230m in thickness. It is Late Campanian to Early Maastrichtian in age and is composed of mudstone, sandstone, and carbonaceous shales...
, along the Red Deer River
Red Deer River
The Red Deer River is a river in Alberta, Canada. It is a major tributary of the South Saskatchewan River.Red Deer River has a total length of and a drainage area of...
in 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...
by a 1923 expedition from the University of Toronto
University of Toronto
The University of Toronto is a public research university in Toronto, Ontario, Canada, situated on the grounds that surround Queen's Park. It was founded by royal charter in 1827 as King's College, the first institution of higher learning in Upper Canada...
.
Only one species is described, A. brachyops. Other material from 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...
, named by Gilmore in 1946, was originally known as A. utahensis, thence transferred to Torosaurus
Torosaurus
Torosaurus is a genus of ceratopsid dinosaur that lived during the late Cretaceous period , between 70 and 65 million years ago. It possessed one of the largest skulls of any known land animal. The frilled skull reached in length...
.
Classification
Arrhinoceratops belonged to the Ceratopsinae (previously known as Chasmosaurinae) within the Ceratopsia (the name is Ancient Greek for "horned face"), a group of herbivorous dinosaurs with parrotParrot
Parrots, also known as psittacines , are birds of the roughly 372 species in 86 genera that make up the order Psittaciformes, found in most tropical and subtropical regions. The order is subdivided into three families: the Psittacidae , the Cacatuidae and the Strigopidae...
-like beaks which thrived in 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...
and Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
during the Cretaceous Period, which ended roughly 65 million years ago. It appears to be closely related to Torosaurus
Torosaurus
Torosaurus is a genus of ceratopsid dinosaur that lived during the late Cretaceous period , between 70 and 65 million years ago. It possessed one of the largest skulls of any known land animal. The frilled skull reached in length...
.
Description
Diet
Arrhinoceratops, like all Ceratopsians, was a herbivoreHerbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
. During the Cretaceous, flowering plants were "geographically limited on the landscape", and so it is likely that this dinosaur fed on the predominant plants of the era: ferns, cycads and conifers. It would have used its sharp Ceratopsian beak to bite off the leaves or needles.
Related animals
These ceratopsians were close relatives of Arrhinoceratops.- AnchiceratopsAnchiceratopsAnchiceratops 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...
- ChasmosaurusChasmosaurusChasmosaurus 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...
- PentaceratopsPentaceratopsPentaceratops is a genus of ceratopsid dinosaur from the late Cretaceous Period of what is now North America. The appearance of Pentaceratops sternbergii in the fossil record marks the end of the Judithian land vertebrate age and the start of the Kirtlandian...
- TorosaurusTorosaurusTorosaurus is a genus of ceratopsid dinosaur that lived during the late Cretaceous period , between 70 and 65 million years ago. It possessed one of the largest skulls of any known land animal. The frilled skull reached in length...