''Zuolong'' (Zuo's dragon) 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 ...

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 ...

which existed in what is now Wucaiwan,

Xinjiang Autonomous Region 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 ...

of China during the

Late Jurassic The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.Owen 1987. In European lithostratigraphy, the name ...

period (lower

Oxfordian stage The Oxfordian is, in the ICS' geologic timescale, the earliest age of the Late Jurassic Epoch, or the lowest stage of the Upper Jurassic Series. It spans the time between 163.5 ± 1.0 Ma and 157.3 ± 1.0 Ma (million years ago). The Oxfordia ...

). It was found in the

Shishugou Formation The Shishugou Formation () is a geological formation in Xinjiang, China. Its strata date back to the Late Jurassic period. Dinosaur remains are among the fossils that have been recovered from the formation.Weishampel, David B; et al. (2004). "Din ...

, Xinjiang, China.

Discovery

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 ...

fossil of ''Zuolong'', IVPP V15912, a partial skeleton with skull, was discovered in 2001 in China, in the upper part of the

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 ...

. It was a subadult animal which measured approximately in length and weighed up to approximately . ''Zuolong'' was named by Jonah N. Choiniere, James M. Clark, Catherine A. Forster and Xu Xing in 2010, and 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 ''Zuolong salleei''. The generic name honours General

Zuo Zongtang Zuo Zongtang, Marquis Kejing ( also spelled Tso Tsung-t'ang; ; November 10, 1812 – September 5, 1885), sometimes referred to as General Tso, was a Chinese statesman and military leader of the late Qing dynasty. Born in Xiangyin County, ...

, who secured Xinjiang for China in the nineteenth century. The specific name honours Hilmar Sallee, whose

bequest A bequest is property given by will. Historically, the term ''bequest'' was used for personal property given by will and ''deviser'' for real property. Today, the two words are used interchangeably. The word ''bequeath'' is a verb form for the act ...

helped finance the research. The specific age for the holotype specimen is 161.2 to 155.2 million years ago. The holotype is considered by Thomas R. Holtz Jr. to almost certainly be from a juvenile theropod.

Description

In 2016,

Gregory S. Paul Gregory Scott Paul (born December 24, 1954) is an American freelance researcher, author and illustrator who works in paleontology, and more recently has examined sociology and theology. He is best known for his work and research on theropod dino ...

estimated the length of ''Zuolong'' at , and its weight at 60 kilogrammes.Paul, G.S., 2016, ''The Princeton Field Guide to Dinosaurs, second edition'', Princeton University Press p. 120 The specimen is probably from a juvenile animal, and is quite complete.

Classification

''Zuolong'' is a basal coelurosaurian, possibly the most basal known. In 2019 it was found to be a member of

Tyrannoraptora Tyrannoraptora is a clade defined as "all descendants of the last common ancestor of ''Tyrannosaurus rex'' and ''Passer domesticus'' (the house sparrow)". The clade was named in 1999 by the American paleontologist Paul Sereno, though in his origi ...

in a polytomy with

Tyrannosauroidea Tyrannosauroidea (meaning 'tyrant lizard forms') is a superfamily (or clade) of coelurosaurian theropod dinosaurs that includes the family Tyrannosauridae as well as more basal relatives. Tyrannosauroids lived on the Laurasian supercontinen ...

and

Maniraptoromorpha Maniraptoromorpha is a clade of coelurosaurian theropod dinosaurs that includes taxa such as '' Ornitholestes'', Compsognathidae and Maniraptoriformes. There have been several phylogenetic analyses that have shown support in the grouping of Manir ...

References

Prehistoric coelurosaurs Oxfordian life Late Jurassic dinosaurs of Asia Jurassic China Fossils of China Paleontology in Xinjiang Fossil taxa described in 2010 Taxa named by Xu Xing Taxa named by Catherine Forster {{theropod-stub