''Chuandongocoelurus'' ( ) is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of carnivorous tetanuran theropod

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

from the

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

Discovery and naming

The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

''Chuandongocoelurus primitivus'' was first described and named by Chinese paleontologist

He Xinlu He or HE may refer to: Language * He (pronoun), an English pronoun * He (kana), the romanization of the Japanese kana へ * He (letter), the fifth letter of many Semitic alphabets * He (Cyrillic), a letter of the Cyrillic script called ''He'' in ...

in 1984. The generic name combines references to the Chuandong in Sichuan Province and the theropod genus '' Coelurus'', itself named after the Greek κοῖλος, ', meaning "hollow" and οὐρά, ', meaning "tail". The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

means "the primitive one" in

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

, a reference to the great age of the find. He assigned two partial skeletons to ''Chuandongocoelurus''. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

, a thighbone, is part of specimen CCG 20010. Vertebrae, pelvic bones and hindlimb elements, also catalogued under this inventory number, may belong to the same individual. The specimen has unfused neurocentral sutures in its vertebrae, meaning that the animal was immature at the time of death. The second specimen, CCG 20011, is a set of neck vertebrae from a much larger individual. In 2012, it was concluded that both specimens represent different taxa, probably not even closely related. CCG 20011 was found to instead share similarities with the ceratosaur ''

Elaphrosaurus ''Elaphrosaurus'' ( ) is a genus of ceratosaurian theropod dinosaur that lived approximately 154 to 150 million years ago during the Late Jurassic Period in what is now Tanzania in Africa. ''Elaphrosaurus'' was a medium-sized but lightly built m ...

''.M.T. Carrano, R.B.J. Benson, and S.D. Sampson, 2012, "The phylogeny of Tetanurae (Dinosauria: Theropoda)", ''Journal of Systematic Palaeontology'' 10(2): 211-300 The formation in which it was discovered was the Lower Shaximiao Formation, meaning ''Chuandongocoelurus'' dates to the

Bathonian In the geologic timescale the Bathonian is an age and stage of the Middle Jurassic. It lasted from approximately 168.3 Ma to around 166.1 Ma (million years ago). The Bathonian Age succeeds the Bajocian Age and precedes the Callovian Age. Strat ...

or Callovian stage of the

Middle Jurassic The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations co ...

. The holotype thighbone has a length of 201 millimetres.

Classification

He placed ''Chuandongocoelurus'' in the Coeluridae,He, 1984. The vertebrate fossils of Sichuan. Sichuan Scientific and Technological Publishing House. 168 pp. at the time a wastebasket taxon including almost all small theropods. David Bruce Norman in 1990 considered it to be an indeterminate theropod. More recently, Roger Benson (2008, 2010) and Benson ''et al.'' (2010) found it to be the

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

of ''

Monolophosaurus ''Monolophosaurus'' ( ; meaning "single-crested lizard") is an extinct genus of tetanuran theropod dinosaur from the Middle Jurassic Shishugou Formation in what is now Xinjiang, China.Holtz, Thomas R. Jr. (2011) ''Dinosaurs: The Most Complete, Up ...

'', together forming a

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

belonging either to Megalosauroidea or outside of Megalosauroidea in the Tetanurae.Benson, Brusatte and Carrano, 2010. A new clade of large-bodied predatory dinosaurs (Theropoda: Allosauroidea) that survived to the latest Mesozoic. Naturwissenschaften. 97, 71-78 In 2012,

Matthew Carrano Matthew may refer to: * Matthew (given name) * Matthew (surname) * ''Matthew'' (ship), the replica of the ship sailed by John Cabot in 1497 * ''Matthew'' (album), a 2000 album by rapper Kool Keith * Matthew (elm cultivar), a cultivar of the Chi ...

''et al.'' found ''Chuandongocoelurus'' outside of the Megalosauroidea. The cladogram below follows Rauhut and Pol (2019):

References

External links

Details on ''Chuandongocoelurus'', from the Dinosaur Mailing List (includes full redescription)
Prehistoric tetanurans Middle Jurassic dinosaurs of Asia Paleontology in Sichuan {{Jurassic-reptile-stub