A new genus and species of thyreophoran dinosaur that lived during the Early Jurassic epoch has been identified from a partial skeleton with cranial and associated postcranial elements found in China.
The newly-identified dinosaur species roamed our planet lived between 192 and 174 million years ago during the Early Jurassic epoch.
Dubbed Yuxisaurus kopchicki, it was a type of a thyreophoran, a group of armored dinosaurs that includes Stegosaurus and Ankylosaurus.
“Thyreophoran dinosaurs were important components of many terrestrial faunas from the Late Jurassic until the end of the Cretaceous, particularly in Laurasia,” said Professor Paul Barrett of the Natural History Museum, London, and his colleagues from China and the United States.
“However, many aspects of their earlier evolutionary history remain contentious and poorly known.”
“The majority of Late Mesozoic armored dinosaurs belonged to one of two major lineages — Ankylosauria or Stegosauria — whose earliest members are currently known from the Middle Jurassic.”
Yuxisaurus kopchicki had a heavy build, distinctive spiked armor and numerous unusual features of its skull, particularly with respect to the bones that would have originally surrounded its brain.
Its fossilized remains — a partial skeleton that includes skull, axial, limb and armor elements — were recovered from the Fengjiahe Formation in China’s Yunnan province.
“Yuxisaurus kopchicki was possibly a facultative quadrupedal,” said Professor Shundong Bi, a paleontologist at Indiana University of Pennsylvania.
“It was primarily adapted for walking on four legs, but also able to walk on two legs.”
According to the team, Yuxisaurus kopchicki is the earliest well preserved armored dinosaur found in Asia to date.
Its discovery confirms the rapid geographic spread and diversification of thyreophoran dinosaurs after their first appearance around 200 million years ago.
“Although we’ve had tantalizing fragments of early armored dinosaurs from Asia, this is the first time we’ve had enough material to recognize a new species from the region and investigate its evolutionary history,” Professor Barrett said.
“I hope it’s the first of many new dinosaurs from the localities being discovered by my colleagues in Yunnan.”
The discovery of Yuxisaurus kopchicki is reported in a paper in the journal eLife.
Xi Yao et al. 2022. A new early-branching armoured dinosaur from the Lower Jurassic of southwestern China. eLife 11: e75248; doi: 10.7554/eLife.75248
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