Asia's earliest known armored dinosaur fossil found in Southwest China
Published: Mar 17, 2022 11:34 AM

a restoration image of Yuxisaurus kopchicki Photo: Courtesy of Chen Yuhui

A restoration image of Yuxisaurus kopchicki Photo: Courtesy of Chen Yuhui

The schematic diagram of the preservation of Yuxisaurus kopchicki fossil Photo: Courtesy of Yao Xihui

The schematic diagram of the preservation of Yuxisaurus kopchicki fossil Photo: Courtesy of Yao Xihui

Chinese scientists have confirmed the discovery of a new taxon of armored dinosaurs (Thyreophora), named "Yuxisaurus kopchicki," that lived during the Early Jurassic (200 million years ago) in what is today Southwest China's Yunnan Province. The scientists also said they plan to carry out further research into how the dinosaur moved and its family relationships.

Although fossils of the dinosaur had been previously found in Yuxi, Yunnan Province, they were not enough to establish a valid species. The new find, for the first time, provided enough fossil materials to identify it as Asia's earliest known thyreophoran dinosaur, according to a press release from the research team on Thursday.

The vertebrate research team at the School of Life Sciences in Yunnan University published the findings in the biology journal eLife on Wednesday.

"The newly found dinosaur will benefit our study of the ecological environment after extinction of some creatures in the Triassic period [250 million BC to 200 million BC]," Xu Xing, one of the co-author of the journal, told the Global Times on Thursday.

According to the journal, Yuxisaurus kopchicki represents the first valid thyreophoran dinosaur from the Early Jurassic in Asia and confirms the rapid geographic spread and diversification of the clade after its first appearance in the Hettangian period, the earliest age and lowest stage of the Jurassic Period on the geologic timescale. 

Yuxisaurus kopchicki, an herbivorous dinosaur, was about 3 meters long. It mainly walked on four legs, but could use its forelimbs to grab the tender leaves of plants when needed. 

Fossils of the species are commonly found in late Jurassic rocks from 150 million years ago, but are rarely found in early Jurassic strata from nearly 200 million years ago. The discovered fossil is a relatively complete skeleton that includes parts of the skull, jaw, vertebrae, limb bones and plates.

Current research indicates that Yuxisaurus kopchicki originated about 200 million years ago, but a specific origin is still unclear. The discovery of the dinosaur in Asia shows that this group quickly differentiated and spread rapidly after its emergence, reaching global distribution within 10,000 years.

According to Xu, the team plans to take some slices from the fossil to study how the dinosaur grew and its relationship with other family members, and to build a three-dimensional model using laser scans to study how it moved.

"The current fossil is still not fully complete. After we fill in the missing pieces, we can also make a 3D printed model for public education," said Xu.

Analysis shows that the new fossils are closely related to armored dinosaurs such as Emausaurus in Germany, but are significantly different from the morphological characteristics of armored dinosaurs such as Ankylosaurus and Stegosaurus.

"Yunnan is the kingdom of paleontology, so we believe that other unnamed dinosaur species will also be discovered in this place," said Xu.