A new armored dinosaur species named Yuxisaurus kopchicki from the early Jurassic period was discovered in southwestern China, according to a study published in the journal eLife earlier this week.
Study author Shundong Bi, professor at the Indiana University of Pennsylvania, said scientists originally found remains of Yuxisaurus kopchicki in 2017 in the Yuxi region of Yunnan province, an area that has been a hotspot for dinosaur discoveries.
According to Bi, more than 120 bone deposits were recovered from the dig site, giving the researchers enough material to confirm a new species. These remains included multiple fragments of a single skeleton with parts of the armor plates, limbs, jaws, and skull. Research on the retrieved specimens started in 2019.
Paul Barrett, a dinosaur researcher at the Natural History Museum in London who helped describe the new species along with his Chinese colleagues, said Yuxisaurus kopchicki belongs to the thyreophoran group, making it a distant cousin of Stegosaurus. Its closest relatives, meanwhile, are the herbivorous Scelidosaurus and the Emausaurus, which both originated in Europe during the Jurassic period.
Likely spanning 6.6 to 9.8 feet (2 to 3 meters) in length, Yuxisaurus kopchicki ate low-growing plants like ferns and cycads.
Similar to other armored dinosaurs, Yuxisaurus kopchicki is encased by bone plates, covering its neck, back, and limbs, with large spikes scattered on top of its exterior. Barrett explained that the spikes have different purposes, including deflecting the jaws and teeth of its predators and possibly being a tool for showing off to other members of its own species during territorial or mate disputes.
Bi said Yuxisaurus kopchicki behaved similarly with the modern-day animals that porcupines and hedgehogs.
According to the study, Yuxisaurus kopchicki likely lived 192 million to 174 million years ago and is the first thyreophoran from that time period to be recognized in Asia.
“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,” 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 confirms the rapid geographic spread and diversification of thyreophoran dinosaurs after their first appearance around 200 million years ago.