Chialingosaurus

*Chialingosaurus kuani*

***Chialingosaurus*** (meaning "Chialing Lizard") is a genus of stegosaur similar to *Kentrosaurus* from the Upper Shaximiao Formation, Late Jurassic beds in Sichuan Province in China. Its age makes it one of the oldest species of stegosaurs, living about 160 million years ago. Since it was an herbivore, scientists think that *Chialingosaurus* probably ate ferns and cycads, which were plentiful during the period when *Chialingosaurus* was alive. Its name is taken from the Chialing River in southern China. Perhaps growing up to four meters long and weighing just 150 kg, much less than other later stegosaurs.

## Discovery

*Chialingosaurus* fossils were found and collected by geologist Kuan Yaowu or Guan Yao-Wu in 1957, Taipingstai in Quxian County, whilst they were surveying the Chialing River in southern China. The type species *Chialingosaurus kuani* was named and described by the paleontologist Yang Zhongjian, in 1959. The genus (Generic name) refers to the Chialing river, while the specefic name (species) honours Kuan. Chialingosaurus was the first stegosaurian described from China.

IVPP 2300 the holotype, was found was found in a layer of the Upper Shaximiao Formation, dating from the Oxfordian-Kimmeridgian. The holotype consists of the partial skeleton lacking the skull. There are six vertebrae, three spines, The humeri, the corocoids, and a right radius. The original material was supplemented after November 1978 by Zhou Shiwu of the Municipal Museum of Chongqing. A second specimen CV 202, was referred, and represents a skeleton with a partial skull and lower jaws, limb elements, some vertebrae, and four plates. The 3rd specimen CV 203, a partial skeleton lacking the skull, was made the paratype. All specimens are either juvenile or subadult.

In 1999, Cai Kaiji, Li Kui, and Zhang Yuguang mentioned a second species: Chialingosaurus guangyuanensis. A description was not provided, and the name is seen as a nomen nudum.

## Description

Yang in 1959 provided a diagnosis, emphasising the slender build of the animal. It might have been only four metres (thirteen feet) long. However, the gracile proportions may have been caused by the subadult age and the remainder of the diagnostic traits were in fact shared by other stegosaurs. In 1990, Peter Malcolm Galton identified just a single autapomorphy: the lesser trochanter of the thighbone is triangular with a broad base. Susannah Maidment in 2008 even listed Chialingosaurus kuani among the invalid stegosaur taxa in her phylogeny of Stegosauria. This was based upon previous work by Maidment & Wei in 2006 in which the authors were unable to identify any autapomorphies or unique character combinations for Chialingosaurus, therefore making it a nomen dubium. Yang modelled Chialingosaurus after Kentrosaurus. Some plates and spine bases having been found, he suggested that the plates were placed on the front upper parts of the animal, the spines at the hip and tail.

## Phylogeny

Yang in 1959 placed Chialingosaurus in the Stegosaurinae within the Stegosauridae. In 1969, Rodney Steel suggested that Chialingosaurus might have actually been an early ancestor of other stegosaurs. However, Galton in 2004 recovered a rather derived position, albeit indeed close to Kentrosaurus. Dong confirmed the placement in the Stegosaurinae.

## Dinosaur Earth Description

Chialingosaurus was a stegosaur dinosaur known from limited fossil remains. This was the first stegosaur to be discovered in Asia. Since its discovery in 1959, a number of these Jurassic period cousins of the famous Stegosaurus have been discovered in the central part of China. In Chialingosaurus, the typical back plates were narrow and spike like. It was medium sized for a stegosaur, with a higher and narrower skull than other family members.

## Links

https://www.dinosaurearth.com/chialingosaurus.html