Good news for the world of paleontology . The new species of stegosaurus, dubbed Bashanosaurus primitivus , is the oldest stegosaurus ever discovered in Asia and one of the earliest anywhere in the world. So much so that it could be the oldest stegosaurus on the planet.
“Our analysis of indicates that it is one of the earliest stegosaurs to diverge along with the Chongqing lizard ( Chungkingosaurus ) and Huayangosaurus ,” Dai Hui of the Chongqing Geological and Mineral Resources Exploration and Development Bureau said in a statement. . “All of these fossils were unearthed from the Middle to Late Jurassic Shaximiao Formation in China, suggesting that stegosaurs could have originated in Asia.”
Although although the research suggests that stegosaurs would have emerged for the first time in Asia, the truth is that it is necessary to investigate further for more deposits around the world.
The stegosaurus, which featured spine-like plates along its entire back, was given the name Bashanosaurus primitivus in a nod to the ancient name of the region of China in which it was found in 2016 and its position in the family tree of the stegosaurs.
It lived about 168 million years ago, making it an early cousin of Stegosaurus, which lived about 150 million years ago and had a stocky build, a pointed tail, and huge kite-shaped plates on its back.
“It has this weird mix of features that we commonly see in fairly primitive armored dinosaurs. Bashanosaurus does not have these large, conspicuous, massive giant plates, which Stegosaurus does ; it has much smaller and thinner plates that are actually quite similar to a spine, ”explains Susannah Maidment, from the Natural History Museum in London and co-author of the study published in the Journal of Vertebrate Paleontology.
Their appearance
Aside from having these little spine-like plates on its back and long spikes on its tail (as well as a fairly small head), it was a relatively small creature: a four-legged, herbivorous dinosaur that stood about 9 feet tall. the snout to the tail, although the experts have not been able to elucidate whether it was a growing specimen or an adult. Despite its differences from the better-known stegosaurs, it bears similarities to some of the earliest armored dinosaurs. His strange armor would have served him well to fight against carnivorous predators such as Allosaurus and Ceratosaurus. In the same way, this natural armor would also have acted as a thermoregulatory mechanism to keep the dinosaur cool and as a tool to attract potential mates.
“All of these features are clues to the place of stegosaurus in the dinosaur family tree,” Dai Hui continues. “ Bashanosaurus can be distinguished from other Middle Jurassic stegosaurus and clearly represents a new species.”
Among the remains discovered in China were back, shoulder, thigh, leg, and rib bones, as well as various armor plates, dating to the Bajocian (171.6 to 167.7 million years ago). ), from the Middle Jurassic period, long before most known stegosaurus.
Considering that it roamed the planet some 168 million years ago, it plays an important role in discovering how stegosaurus evolved , about which, to this day, little is known.
The origin
The first discovered stegosaurus, Dacentrurus, was found in Swindon, UK, in 1874 and was described by Richard Owen, the scientist who coined the term dinosaur. Three years later, in 1877, Othniel Charles Marsh unearthed Stegosaurus armatus, after which the group is named, in the Rocky Mountains of the United States.
Stegosaurus fossils have been found on every continent except Antarctica and Australia, and 14 species of stegosaurus have been identified so far.
Referencia: “New Stegosaurs from the Middle Jurassic Lower Member of the Shaximiao Formation of Chongqing, China” by Dai Hui, Li Ning, Susannah CR Maidment, Wei Guangbiao, Zhou Yuxuan, Hu Xufeng, Ma Qingyu, Wang Xunqian, Hu Haiqian and Peng Guangzhao, 3 March 2022, Journal of Vertebrate Paleontology.
DOI: 10.1080/02724634.2021.1995737
