''Yuzhoulong'' (meaning "

Chongqing ChongqingPostal Romanization, Previously romanized as Chungking ();. is a direct-administered municipality in Southwestern China. Chongqing is one of the four direct-administered municipalities under the State Council of the People's Republi ...

dragon", after ''Yuzhou'', an early name for Chongqing) is a genus of

macronaria Macronaria is a clade of sauropod dinosaurs. Macronarians are named after the large diameter of the nasal opening of their skull, known as the external naris, which exceeded the size of the orbit, the skull opening where the eye is located (hence ...

sauropod Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their b ...

dinosaur from the

Middle Jurassic The Middle Jurassic is the second Epoch (geology), epoch of the Jurassic Period (geology), Period. It lasted from about 174.1 to 161.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relativel ...

Shaximiao Formation The Shaximiao Formation () is a Middle to Late Jurassic aged geological formation in Sichuan, China, most notable for the wealth of dinosaurs fossils that have been excavated from its strata. The Shaximiao Formation is exposed in and around the ...

of Chongqing, China. The type and only species is ''Yuzhoulong qurenensis''.

Discovery and naming

After the discovery of a new quarry from the

in 2016, the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

of ''Yuzhoulong'', CLGRP V00013, was discovered in Pu'an town in

Yunyang County Yunyang County () is a county in the northeast of Chongqing Municipality, China, bordering Hubei Hubei is a province of China, province in Central China. It has the List of Chinese provincial-level divisions by GDP, seventh-largest economy a ...

in Chongqing. It was named as a distinct genus and species by Dai ''et al''. in 2022. The generic name, "''Yuzhoulong''", honors "Yuzhou", the ancient name of

, while 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 ...

, "''qurenensis''", is derived from Quren, the ancient name of Yunyang.

Description

''Yuzhoulong'' is only known from a partial skeleton, including a partial skull, of an immature subadult individual. It was partially buried in the rock at the time of its description, mixed in with the fossils of another, unnamed sauropod.

Classification

In 2022, Dai ''et al.'' added ''Yuzhoulong'' to a number of different

phylogenetic analyses In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as Computational phylogenetics, phylogenetic inference. It infers the relationship among organ ...

, which consistently recovered as it a basal macronarian. This proves that macronarians existed by at least the Middle Jurassic, indicating a higher diversity of neosauropods in this age. The

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

below displays the results of one of their phylogenetic analyses.

References

{{Taxonbar, from=Q115011290 Macronaria Dinosaur genera Bathonian dinosaurs Shaximiao Formation Dinosaurs of China Fossil taxa described in 2022