Camposaurus
Encyclopedia
Not to be confused with Camptosaurus
Camptosaurus
Camptosaurus is a genus of plant-eating, beaked ornithischian dinosaurs of the Late Jurassic period of western North America. The name means 'flexible lizard', ....

.

Camposaurus (meaning "Charles Lewis Camp
Charles Lewis Camp
Charles Lewis Camp was a notable palaeontologist and zoologist, working from the University of California, Berkeley...

's lizard") is a coelophysoid 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...

 genus
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...

 from the Late Triassic
Late Triassic
The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...

 of 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...

. With fossils dating back to the early to middle Norian
Norian
The Norian is a division of the Triassic geological period. It has the rank of an age or stage . The Norian lasted from 216.5 ± 2.0 to 203.6 ± 1.5 million years ago. It was preceded by the Carnian and succeeded by the Rhaetian.-Stratigraphic definitions:The Norian was named after the Noric Alps in...

 stage, it is the oldest known neotheropod. It is known from partial lower leg bones, 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...

 UCMP 34498, and other fragmentary material. Like other coelophysid
Coelophysidae
The Coelophysidae are a family of primitive carnivorous theropod dinosaurs. Most species were relatively small in size. The family flourished in the Late Triassic and Early Jurassic periods....

s, it has fused tibio-tarsals and fibula-tarsals. Unlike its relatives, the area of the tibia
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....

 that fits with the fibula has a distinct ridge at the back. Another unique feature is the lack of a large medial condyle on the astragalus
Talus bone
-External links:* *...

.

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...

, C. arizonensis, was formally named and described by Adrian Hunt, Spencer G. Lucas
Spencer G. Lucas
Spencer George Lucas is an American paleontologist and stratigrapher, and curator of paleontology at the New Mexico Museum of Natural History and Science. His main areas of study are late Paleozoic, Mesozoic and early Cenozoic vertebrate fossils, stratigraphy, and continental deposits,...

, Andrew B. Heckert, Robert Sullivan
Robert Sullivan
Robert Sullivan may refer to:*Robert Sullivan *Robert Baldwin Sullivan, Canadian lawyer, judge, and the second Mayor of Toronto*Robert J. Sullivan, Jr. , American politician...

 and Martin Lockley
Martin Lockley
Dr. Martin G. Lockley is an English paleontologist specializing in dinosaur tracks. He is a Professor of Geology at the University of Colorado at Denver, in the United States, and founder and director of the Dinosaur Trackers Research Group.-Biography:...

 in 1998. As the species name suggests, it was by Camp found in Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...

, in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. It was similar to, and has actually been considered a species of, Coelophysis
Coelophysis
Coelophysis , meaning "hollow form" in reference to its hollow bones , is one of the earliest known genera of dinosaur...

. The lack of material has led many paleontologists to reject it as a nomen dubium
Nomen dubium
In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...

, or doubtful name. Camposaurus has more recently been considered a valid taxon based on the two unique features, autapomorphies, of the leg bones. In 2011, it was placed in a phylogenetic analysis and found to be a close relative of Megapnosaurus rhodesiensis (considered to be a species of Coelophysis in the analysis).
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