Tiny new species of stegosaurus discovered in China

A fossilized Stegosaurus recently discovered in China is the oldest ever found in Asia and may be the oldest in the world.

Walking the Earth around 170 million years ago, during the Middle Jurassic Bajocian era, the beast was also small for a Stegosaurus, measuring just 2.8 meters (just over 9 feet) from its nose. at the end of its thorny tail; larger stegos could reach 9 meters in length.

It’s unclear whether the specimen is an adult or a baby, but its discovery could tell us more about the evolution of the genus stegosaurus – a process we know woefully little about.

The remains consisted of bones from the shoulder, back, thigh, feet, spine, and ribs, as well as several armor plates. These allowed a team of paleontologists led by Dai Hui from the Chongqing Geological and Mineral Resources Exploration and Development Bureau to make comparisons with other stegosaur species.

They found that while the newly found stego, named Bashanosaurus primitivus, has features in common with other stegosaurs, some features seem unique. Its shoulder is smaller and less developed, its femur is slightly different, and its armor plates are narrower, but thicker at the base.

Interestingly, it also shares some characteristics with the first armored dinosaurs, which lived some 20 million years earlier. This suggests that Bashanosaurus could be a “missing link” between these older dinosaurs and the more recent stegosaurs.

Bashanosaurus distinguishes itself from other Middle Jurassic stegosaurs and clearly represents a new species”, Hui said.

“Furthermore, our family tree analysis indicates that it is one of the earliest divergent stegosaurs along with the Chongqing lizard (chungkingosaurus) and Huayangosaurus. These were all discovered in the Middle to Late Jurassic Shaximiao Formation in China, suggesting that stegosaurs may have originated in Asia.”

Stegosaurus are among the most beloved Jurassic dinosaurs. The herbivorous beast was protected by armor plates running the length of its spine and wicked spikes protruding from the end of its tail, wielding like a club.

Other characteristics include quadrupedal locomotion and a tiny, surprisingly delicate head on such a tank-like body.

These physical traits are characteristic of the gender, and Bashanosaurus seems to have had it too. But it also has some similarities with the first thyreophoresthe armored dinosaurs from which the stegosaurs descended, as well as the first stegosaurs such as giantspinosaurus and Huayangosaurusboth also from China.

These similarities can be seen in the tail vertebrae, which are more elongated; a narrower but flared shoulder blade; and a lack of deep depressions in the spinal vertebrae. These similarities and differences suggest that Bashanosaurus is placed quite early in the Stegosaurus family tree, which means it represents a fairly important discovery for understanding the genus.

“The discovery of this Middle Jurassic stegosaurus from China adds to a growing body of evidence that the group evolved during the Early Middle Jurassic, or possibly even the Early Jurassic, and as such represents some of the earliest known dinosaurs. with hips of birds.”, said paleontologist Susannah Maidment from the London Natural History Museum in the UK.

“China appears to have been a hotspot for stegosaur diversity, with many species now known from the Middle Jurassic through the Late Lower Cretaceous.”

The research was published in the Journal of Vertebrate Paleontology.

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