Fossil of new dinosaur found in Chongqing

Fossil remains of a new genus of plant-eating dinosaur — Bashanosaurus primitivus — found in Chongqing are those of a stegosaurus that roamed the earth around 169 million years ago during the Middle Jurassic period, a scientific paper said recently. The animal is the oldest of its kind to be discovered on the continent, suggesting that stegosaurs may have originated in Asia.

The Chongqing Municipal Planning and Natural Resources Bureau noted the publication of the paper in the March 4 issue of the Journal of Vertebrate Paleontology, a bimonthly peer-reviewed scientific journal that covers all aspects of vertebrate paleontology.

The meticulous excavation work and analysis began in 2018.

The paper said the fossils — including bones from the back, shoulder, thigh, feet, ribs and several armor plates — were found at the original site of the lower Shaximiao Formation, from which a number of dinosaur remains have been excavated in Chongqing's Yunyang county.

The relatively small stegosaurus measures about 2.8 meters from nose to tail. But scientists can't tell whether the remains are those of an adult or a juvenile.

A team from the Chongqing Bureau of Geological and Mineral Resource Exploration and Development in China, working with London's Natural History Museum, named the animal Bashanosaurus primitivus — "Bashan" in reference to the place in Chongqing where it was found, and the Latin word "primitivus", meaning first.

"All the features are clues to the stegosaurs' place on the dinosaur family tree," said Dr. Dai Hui of the Chongqing Bureau of Geological and Mineral Resource Exploration and Development, who was the lead author of the paper. "Bashanosaurus can be distinguished from other Middle Jurassic stegosaurs, and clearly represents a new genus."

Stegosaurus fossils were first discovered in Britain in 1874. Later on, more were found on all continents except for Australia and Antarctica. Seventeen genuses of stegosaurs have been identified so far.

Dai said the stegosaurus in China, which is rich in species, accounts for about 40 percent of the world's known examples. The new find gives China two of the world's four oldest stegosaurs — the others being in Morocco and Argentina. One in China was found in Zigong, Sichuan province; the other is the one found recently in Chongqing. All are from the Middle Jurassic period.

"The discovery of this stegosaur from the Middle Jurassic in China adds to an increasing body of evidence that the group evolved in the early Middle Jurassic, or perhaps even in the Early Jurassic. So they represent some of the earliest known bird-hipped dinosaurs," said Dr. Susannah Maidment, a palaeontologist at London's Natural History Museum and co-author of the paper.

"China seems to have been a hot spot for stegosaur diversity, with numerous species now known from the Middle Jurassic all the way through to the end of the Early Cretaceous period."