''Datonglong tianzhenensis'' is an 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 ...

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 ...

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, Euro ...

, which lived in 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'', ...

period in present-day China. It is 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( ...

of the genus ''Datonglong''.

Discovery and naming

In 2008, a team from the Shanxi Museum of Geological and Mineral Science and Technology in the Kangdailiang quarry in

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 ...

discovered the jaw of a euornithopod. In 2016, the species ''Datonglong tianzhenensis'' was named and described by Xu Shicha, You Hailu, Wang Jiawei, Wang Suozhu, Yi Jian, and Jia Lei. The generic name refers to the city of

Datong Datong is a prefecture-level city in northern Shanxi Province in the People's Republic of China. It is located in the Datong Basin at an elevation of and borders Inner Mongolia to the north and west and Hebei to the east. As of the 2020 cen ...

and the Chinese word ''long'' (龍), which means “dragon”. The specific name refers to its origins in Tianzhen county. ''Datonglong'' was one of eighteen dinosaur taxa from 2015 to be described in open access or free-to-read journals.

Description

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 seve ...

, SXMG V 00005, consists of a portion of the lower jaw with some preserved teeth. The fossil was found in a layer of the

Huiquanpu Formation The Huiquanpu Formation () is a geological formation in Shanxi and Hebei provinces, China, whose strata date back to the Late Cretaceous period. It predominantly consists of purple-red mudstone, with subordinate grey-white sandy conglomerates. Di ...

. Though the exact time the fossil was deposited is unknown, it is believed to date from somewhere in the Cenomanian-

Campanian The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campani ...

timeframe, roughly 95 to 80 million years ago. ''Datonglong'' was described as a new genus because of its unique dental structures. In the middle and back of the jaw are two functional teeth in each tooth position. Further, the main ridge of the tooth on the inner side is situated more to the back, while the secondary ridge is well developed. There are no further vertical ridges. The top of the tooth crown is bent slightly backwards. The only known fossil of dinosaur's dentarium has a length of and contains at least twenty-seven tooth positions, though it is believed it may have possessed up to twenty-nine tooth positions. The ''processus coronoides'' is vertically oriented. The teeth are large, standing up to for a tooth not yet broken out. Teeth stand in groups of three or four in the tooth battery.

Classification

''Datonglong'' is in the

clade, and is closely related to, but not part of, the

Hadrosauridae Hadrosaurids (), or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae. This group is known as the duck-billed dinosaurs for the flat duck-bill appearance of the bones in their snouts. The ornithopod family, which incl ...

family. However, this placement is not based on an exact

cladistic 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 ch ...

analysis.

References

{{Taxonbar, from=Q22580486 Hadrosaurs Late Cretaceous dinosaurs of Asia Fossil taxa described in 2016 Paleontology in Shanxi Ornithischian genera

Discovery and naming

Description

Classification

See also

References