Chaoyangsaurus ‭(‬Chaoyang lizard‭)‬

Short Info

Chaoyangsaurus ‭(‬Chaoyang lizard‭)‬

Phonetic : Chow-yang-sor-us.

Named By : X.‭ ‬Zhao,‭ ‬Z.‭ ‬Cheng‭ & ‬X.‭ ‬Xu‭ ‬-‭ ‬1999

Diet : Herbivore

Size : U‬ncertain due to lack of fossils,‭ ‬but roughly estimated to be about‭ ‬1‭ ‬meter long

Type of Dinosaur : Ceratopsian

Type Species : C.‭ ‬youngi‭ (‬type‭)

Found in : China,‭ ‬Liaoning‭ ‬-‭ ‬Tuchengzi Formation

When it Lived : Late Jurassic, 152-145 million years ago

Chaoyangsaurus (“Chaoyang the lizard”) is an extinct dinosaur of the marginocephalian era from the Late Jurassic of China. It was dated somewhere between 150.8 to 145.5 millions of years ago. Chaoyangsaurus was part of the Ceratopsia (Greek meaning “horned faces”). Chaoyangsaurus as with all ceratopsians was, in the main, an herbivore.


Chaoyangsaurus
Jaime A. Headden, CC BY 3.0, via Wikimedia Commons


In 1976 fossil remains from Chaoyangsaurus were discovered at the feet of Cheng Zhengwu at Ershijiazi, located in the Chaoyang region located in Liaoning Province in northeastern China. The fossil was then added to a traveling exhibit.

In contrast to other dinosaurs, Chaoyangsaurus was mentioned in numerous sources prior to its official publication. Because of this, a variety of names have been republished as invalid noma nuda (“naked names” names that have no official description behind their names). The first name that was available to printed was Chaoyoungosaurus that was published in the book that accompanied an Japanese museum exhibit. It was due to an error in transliteration of Chinese in the Latin alphabet. Zhao Xijin in 1983 also employed this spelling when he initially talked about the species, but again not having a description which is why it’s technically an unspecified nomen nudum. A few months later Zhao once more used this spelling in the early days when he assigned the its name to the species, Chaoyoungosaurus laosiensis.

According to Dong Zhiming’s 1992 book the name Chaoyoungosaurus was first identified in a separate study in a separate paper by Zhao as well as Cheng in 1983. However, there was no citation for the paper was provided in the following years, and Cheng along with Zhao themselves didn’t consider the name as valid due to the fact that the paper had not yet been published. Dong in his book published in 1992, on Chinese dinosaurs, also changed his name, renaming it to it’s “correct” spelling of Chaoyangosaurus (note the addition of the”o” “o”). However, as this renaming was not followed by any formal description of the animal, Chaoyangosaurus should be considered to be to be a nomen nudum as well.

It wasn’t in 1999, however that dinosaurs was given a name. Paul Sereno in 1999 used the name Chaoyangsaurus in his review of the evolution of dinosaurs. The name, as always, was not a nomen nudum. In December of the year in question, Cheng, Zhao, and XuXing issued an official description under Chaoyangsaurus youngi. Chaoyangsaurus youngi. It is the only name for this genus that’s not a nomen nudum has the official title over other spellings employed. The generic name is a reference to Chaoyang. The name specifically honors one of the Chinese paleontologist Yang Zhongjian (“C. C. Young”) as the pioneer of Chinese vertebrate paleontology.

The Holotype, IGCAGSV371 is located in a layer of Tuchengzi Formation which was discovered in 1999 and dated to late Tithonian. It is comprised of a part of a skull skeleton. It includes the lower portion and the braincase in the skull. Also, it contains jaws of the lower seven neck vertebrae, the shoulder blade on right as well as the right humerus. It’s a mature human. The fossil was made by Ding Jinzhao and Wang Haijun.

In the year 2010 Gregory S. Paul estimated the length of Chaoyangsaurus at one metre and its weight of which was six kilograms.

The authors who wrote the description noted certain distinct characteristics. The boss of the jugal bone is not fully developed and has smooth surfaces. The convex quadratojugal bone is overlapping with the shaft at the rear that is the bone of the quadrate. The quadrate is not wide on its side surface and is not stretched towards the rear. The lower portion of the rear of the quadrate has a convex. The coronoid process in the jaw’s lower part is low, with flat top. The planes of the sides and the underneath of the angular bones are separated by an incline. The five characteristics that were mentioned above were regarded as autapomorphies.

The skull measures 14 centimetres in length. To the side, the lower margin of the bone’s rostral in the past likely covered by horn, is adorned with four crenulations. To the rear of the bone there are two conical premaxillary tooth that extend to below. The maxillary teeth that are transversely flattened number between eight and nine, and there are 11 dentary teeth within the jaw’s lower region, for the total of 44 teeth for the head in all. The teeth on the cheeks are imbricated and are vertically quite long. Both sides are covered in enamel.

Source: Wikipedia