''Zuoyunlong'' is an extinct

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 herbivorous

ornithischian Ornithischia () is an extinct order of mainly herbivorous dinosaurs characterized by a pelvic structure superficially similar to that of birds. The name ''Ornithischia'', or "bird-hipped", reflects this similarity and is derived from the Greek st ...

dinosaur belonging to the

Hadrosauroidea Hadrosauroidea is a clade or superfamily of ornithischian dinosaurs that includes the "duck-billed" dinosaurs, or hadrosaurids, and all dinosaurs more closely related to them than to ''Iguanodon''. Their remains have been recovered in Asia, Europ ...

, that lived during the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

in the area of present

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

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 ...

, SXMG V 00 004, was found by the team of the Shanxi Regional Geological Survey in a layer of the Zhumapu Formation in the province of

Shanxi Shanxi (; ; formerly romanised as Shansi) is a landlocked province of the People's Republic of China and is part of the North China region. The capital and largest city of the province is Taiyuan, while its next most populated prefecture-lev ...

which dates from the

Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...

, roughly ninety-five million years old. It consists of two bones from the right-hand half of the pelvis, a partial right ilium with the field number ZY004-001 to which the cover sheet is missing, and the lower end of the shaft of the right ischium, field number ZY004-002. Additional specimens are unassigned. In 2017 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 ...

''Zuoyunlong huangi'' was named and described by Wang Runfu, You Hailu, Wang Suozhu, Shichao Xu, Yi Jian, Xie Lijuan, Jia and Lei Xing Hai. The generic name refers to the prefecture of

Zuoyun Zuoyun County is a county in the north of Shanxi province, China, bordering Inner Mongolia to the north. It is the westernmost county-level division of the prefecture-level city A prefecture-level city () or prefectural city is an administr ...

with the

Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation ** List of ethnic groups in China, people of ...

word ''long'', "dragon". The specific name honors the Chinese paleontologist Huang Weilong.

Description

The descriptors established a unique feature derived, or

autapomorphy 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 ...

for this taxon: the back sheet of the ilium has only half the length of the main body. The ilium has a preserved length of sixty-two centimeter indicating a body length of about eight meters. The shaft of the buttock ends in a side view in large "foot" the tip of which points obliquely downwards and forwards. The shaft is much higher than transverse width.

Classification

cladistic analysis Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived chara ...

found that ''Zuoyunlong'' had a basal position in the

, as sister taxon of '' Probactrosaurus''. ''Zuoyulong'' was thus in 2015 the most basal hadrosauroid known from the Upper Cretaceous. As the oldest known hadrosauroid outside Asia, ''

Eolambia ''Eolambia'' (meaning "dawn lambeosaurine") is a genus of herbivorous hadrosauroid dinosaur from the early Late Cretaceous of the United States. It contains a single species, ''E. caroljonesa'', named by paleontologist James Kirkland in 1998 ...

'' and ''

Protohadros ''Protohadros'' (meaning "first hadrosaur") is a genus of herbivorous ornithischian dinosaur from the Late Cretaceous ( Cenomanian stage). Gary Byrd, a part-time palaeontologist, discovered some remains of this euornithopod (ribs and an ungual) ...

'' from North America, also date from the Cenomanian, the descriptors considered that is likely that ''Zuoyunlong'' was close to the separation between the Asian and North American hadrosauroids.

References

{{Taxonbar, from=Q21721433 Hadrosaurs Late Cretaceous dinosaurs of Asia Fossil taxa described in 2015 Paleontology in Shanxi Ornithischian genera

Discovery and naming

Description

Classification

See also

References