The remains of a new type of dinosaur with nail armor have been discovered in southwestern China.
Paleontologists said the species is a thyreophoran, a group that also includes Stegosaurus and Ankylosaurus, and it lived about 192-174 million years ago during the early Jurassic period.
Named Yuxisaurus kopchicki, it is the earliest well-preserved armored dinosaur found in Asia to date.
The new species had a heavy build, distinctive spiked armor and numerous unusual features of its skull, especially regarding the bones that would have surrounded its brain.
Scientists led by the Natural History Museum in London described it from specimens found in southwestern China’s Yunnan province.
Scary: The remains of a new type of nail-armored dinosaur called Yuxisaurus kopchicki (pictured in an artist’s reconstruction) have been discovered in southwestern China
Paleontologists said the species is a thyreophoran, a group that also includes Stegosaurus and Ankylosaurus, and it lived about 192-174 million years ago during the early Jurassic period. It was described from specimens (pictured) found in Yunnan Province, in China
IMPORTANT FACTS ABOUT YUXISAURUS KOPCHICKI
lived: About 192-174 million years ago
Place: Yunnan Province, in China
Scientific name: Yuxisaurus head chickic
Most important features: Distinctive armor with spikes and numerous unusual features of his skull, especially with regard to the bones that are said to have surrounded his brain
Family: The new species is a thyreophoran, a group that also includes Stegosaurus and Ankylosaurus
First author Professor Paul Barrett said: ‘While we’ve had tantalizing fragments of early armored dinosaurs from Asia, this is the first time we have enough material to recognize a new species from the region and explore its evolutionary history.
“I hope it’s the first of many new dinosaurs from the areas discovered by my colleagues in Yunnan.”
The remains consisted of a single incomplete skeleton, including parts of the skull, jaws, vertebral column, shoulder girdle, limbs and numerous armor spines and plates.
Professor Barrett and colleagues from Yunnan University, the Chinese Academy of Sciences and the Indiana University of Pennsylvania named the new species Yuxisaurus kopchicki.
Yuxisaurus refers to the site in Yuxi Prefecture, China, and kopchicki to molecular biologist Dr. John J. Kopchick, in recognition of his contributions to biology and the Indiana University of Pennsylvania.
dr. Shundong Bi, a professor at Indiana University of Pennsylvania and senior author of the paper, said, “Yuxisaurus may have been a facultative quadruped.
“It was initially adapted to walk on four legs, but also to walk on two legs.”
The researchers said their discovery confirmed the rapid geographic distribution and diversification of this group of dinosaurs after the species first appeared about 200 million years ago.
The remains consisted of a single incomplete skeleton, including parts of the skull, jaws, vertebral column, shoulder girdle, limbs and a large number of armor spines and plates
The new species had a heavy build, distinctive spiked armor and many unusual features of its skull, especially regarding bones that would have surrounded its brain.
“A partial skeleton collected from the Fengjiahe Formation in the Lower Jurassic in Yunnan Province, China, represents a new taxon of the early diverging thyreophoran dinosaur, which we call Yuxisaurus kopchicki,” they wrote in their paper.
It can be distinguished from all other thyreophorans by a series of autapomorphic cranial, axial and appendicular character states, as well as a unique combination of character states.
“Yuxisaurus represents the first unambiguous armored dinosaur recovered from the Lower Jurassic of Asia and is based on associated diagnostic material and is the first complete enough to be included in a phylogenetic analysis.”
The researchers added, “Yuxisaurus helps highlight the pan-Laurasiatic (and possibly global) distribution of early thyreophorans, their diverse morphology and ecology, and the rate of their initial radiation.”
The study is published in eLife.
Experts have identified the species based on remains found in southwestern China’s Yunnan province
WHAT ARE THE ANKYLOSAURID DINOSAURS AND WHAT DO WE KNOW ABOUT THEM?
One of the most impressive weapons to appear during the Cretaceous dinosaur arms race was the bony tail club wielded by some members of a group of tank-like herbivores.
Its distinguishing feature—a bat used in combat that would have given even the ferocious Tyrannosaurus rex cause for concern—was possessed by the heavily armored dinosaur ankylosaurus and its cousins.
Researchers have studied fossils of a group known as ankylosaurs, which include primitive species without a tail club, and those with a fully developed defensive bone on the tail, which appeared later.
Ankylosaurs began developing tail clubs much earlier than previously thought, a 2015 study found, and the clubs evolved in two steps over tens of millions of years.
Ankylosaurs lived at a time when the largest land predators in Earth’s history, including T. rex, roamed the landscape, ripping apart other dinosaurs with powerful jaws and jagged teeth.
First, the vertebrae in the posterior part of the tail changed, so that the tail became stiff.
Then, bones that form in the skin to provide body armor, known as osteoderms, grew very large at the tip of the tail and completely encased the tip of the tail into a mace that could be swung at an enemy.
Ankylosaurs were dinosaurs with broad bodies and four legs covered with bony plates and spines.
The oldest known ankylosaur dates to about 160 million years ago, during the Jurassic period.
Ankylosaurs from China were crucial to understanding the origin of the tail club, including Gobisaurus, from about 92 million years ago, and Liaoningosaurus, from about 122 million years ago.
Asian ankylosaurids had more pronounced points covering their skulls, compared to the smooth-bones armor of their North American counterparts.
The first fully formed tail club of ankylosaurs appeared about 75 million years ago during the Cretaceous Period.
Ankylosaurus, at about six meters in length, was the largest and last of the ankylosaurs, living about 65 million years ago at the end of the dinosaur age.