''Xinjiangovenator'' (meaning "

Xinjiang Xinjiang, SASM/GNC: ''Xinjang''; zh, c=, p=Xīnjiāng; formerly romanized as Sinkiang (, ), officially the Xinjiang Uygur Autonomous Region (XUAR), is an autonomous region of the People's Republic of China (PRC), located in the northwest ...

hunter") is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

coelurosaur Coelurosauria (; from Greek, meaning "hollow tailed lizards") is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. Coelurosauria is a subgroup of theropod dinosaurs that includes compsognathids, tyran ...

ian dinosaurs, possibly part of the group

Maniraptora Maniraptora is a clade of coelurosaurian dinosaurs which includes the birds and the non-avian dinosaurs that were more closely related to them than to ''Ornithomimus velox''. It contains the major subgroups Avialae, Deinonychosauria, Oviraptoros ...

, which lived during the Early Cretaceous

period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

, sometime between the

Valanginian In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 139.8 ± 3.0 Ma and 132.9 ± 2.0 Ma (million years ago). The Valanginian Stage succeeds the Berriasian Stage of the Lower Cretace ...

and

Albian The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous Epoch/ Series. Its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± 0 ...

stages. The remains of ''Xinjiangovenator'' were found in the Lianmuqin Formation of Wuerho,

, China, and were first described by

Dong Zhiming Dong Zhiming (Chinese: 董枝明, Pinyin: ''Dǒng Zhimíng''; born January 1937) is a Chinese vertebrate paleontologist formerly employed at the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in Beijing. He began working at th ...

in 1973. The genus is based on a single specimen, an articulated partial right lower leg, containing the

tibia The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it connects ...

, three pieces of the

fibula The fibula or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. Its upper extremity i ...

, the

calcaneum In humans and many other primates, the calcaneus (; from the Latin ''calcaneus'' or ''calcaneum'', meaning heel) or heel bone is a bone of the tarsus of the foot which constitutes the heel. In some other animals, it is the point of the hock. ...

and the

astragalus ''Astragalus'' is a large genus of over 3,000 species of herbs and small shrubs, belonging to the legume family Fabaceae and the subfamily Faboideae. It is the largest genus of plants in terms of described species. The genus is native to tempe ...

. This specimen, IVPP V4024-2, is 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 sever ...

of the genus. The holotype was originally thought to be another specimen of ''

Phaedrolosaurus ''Phaedrolosaurus'' is a genus of theropod dinosaur, based on a single tooth possibly from the Valanginian-Albian-age Lower Cretaceous Lianmugin Formation of Wuerho, Xinjiang, People's Republic of China, China. Discovery and naming The first kn ...

''. However, ''Phaedrolosaurus'' is based only on a non-diagnostic tooth, so the hindlimb bones were given their own genus by

Oliver Rauhut Oliver may refer to: Arts, entertainment and literature Books * ''Oliver the Western Engine'', volume 24 in ''The Railway Series'' by Rev. W. Awdry * '' Oliver Twist'', a novel by Charles Dickens Fictional characters * Ariadne Oliver ...

and Xu Xing in 2005. 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 specime ...

is ''Xinjiangovenator parvus''. The generic name is derived from the autonomous region of Xinjiang and

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 ...

''venator'', "hunter". The specific name ''parvus'' means "small" in Latin. The lower leg (tibia plus ankle bones) has a length of 312 millimeters (12.3 inches). Gregory S. Paul estimated in 2010 that ''Xinjiangovenator'' individuals had a length of 3 meters and a mass of 70 kg. Paul, G. S. (2010). ''

The Princeton Field Guide to Dinosaurs ''The Princeton Field Guide to Dinosaurs'' is a reference work on dinosaurs written by the paleontologist and paleoartist Gregory S. Paul. It was first published by Princeton University Press in 2010. In the United Kingdom it was published by A ...

''. Princeton University Press, p. 100. Rauhut & Xu (2005) established two

autapomorphies In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to t ...

(unique derived traits) that could be used to characterize ''Xinjiangovenator''. First, the lateral condyle (outer ankle joint) at the lower end of the tibia extends further backwards than the outer edge of the portion of the tibia near the knee. Secondly, the proximal part of the fibula (near the knee) has a longitudinal groove along its front edge.

Classification

Rauhut & Xu (2005) originally placed ''Xinjiangovenator'' within the coelurosaur subgroup

using a phylogenetic analysis. It was considered to be more closely related to paravians such as

dromaeosaurids Dromaeosauridae () is a family of feathered theropod dinosaurs. They were generally small to medium-sized feathered carnivores that flourished in the Cretaceous Period. The name Dromaeosauridae means 'running lizards', from Greek ('), meaning ...

and birds, rather than oviraptorosaurians and

therizinosaurs Therizinosaurs (once called segnosaurs) were large herbivorous theropod dinosaurs whose fossils have been found across the Early to Late Cretaceous deposits in Asia and North America. Various features of the forelimbs, skull and pelvis unite thes ...

. This placement was justified by the presence of a tall and wide ascending process of the astragalus bone. In addition, the fibular condyle of the femur expanded backwards and the fibula tapered drastically towards the ankle. These characteristics were also found to be present in the coelurosaur ''

Bagaraatan ''Bagaraatan'' (/'ba-ɣa-raa-tan/ meaning 'small' ''baɣa'' + 'carnivorous animal, beast of prey' ''araatan'' in Mongolian) is a genus of theropod dinosaur from the Late Cretaceous period. Its fossils were found in the Nemegt Formation of Mongoli ...

,'' and Rauhut & Xu (2005) suggested that ''Xinjiangovenator'' and ''Bagaraatan'' were

sister taxa 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 ...

. The 2010 description of '' Zuolong'' by Jonah Choiniere, James M. Clark,

Catherine Forster Catherine Ann Forster is an American paleontologist, taxonomist and expert in ornithopod evolution and ''Triceratops ''Triceratops'' ( ; ) is a genus of herbivorous chasmosaurine ceratopsid dinosaur that first appeared during the late ...

, & Xu Xing found a different position for ''Xinjiangovenator'' in their phylogenetic analysis. Due to its fragmentary nature, ''Xinjiangovenator'' was found to have an unstable position within Coelurosauria. Some, but not all, of the phylogenetic trees found ''Xinjiangovenator'' as the sister taxon to ''

Ornitholestes ''Ornitholestes'' (meaning "bird robber") is a small theropod dinosaur of the late Jurassic (Brushy Basin Member of the Morrison Formation, middle Kimmeridgian age, about 154 million years agoTurner, C.E. and Peterson, F., (1999). "Biostratigrap ...

'' based on the proximal part of the tibia being just as wide along its front edge as its rear edge. When ''Xinjiangovenator'' was removed from the analysis, ''Ornitholestes'' was found to be a basal maniraptoran.

References

{{Taxonbar, from=Q609659 Prehistoric maniraptorans Early Cretaceous dinosaurs of Asia Fossil taxa described in 2005 Taxa named by Xu Xing Paleontology in Xinjiang