Xuanhanosaurus is a type of dinosaur that lived about 166 million years ago during the Middle Jurassic period.
This dinosaur was discovered in China, in a place called the Sichuan Basin.
Xuanhanosaurus means “Xuanhan lizard.” The name was given by a scientist named Dong Zhiming in 1984. The first specimen of this dinosaur was found in 1979 during a fossil survey in Sichuan.
The dinosaur is known by its official name, Xuanhanosaurus qilixiaensis. This was named after a town called Qilixia near where the fossils were found.
The fossils include parts of its skeleton, such as shoulder bones, arm bones, and some back bones. However, it does not have a complete skull.
Xuanhanosaurus was roughly 4.8 meters long, which is about 16 feet, and it weighed around 265 kilograms, similar to the weight of a small car.
One interesting feature of Xuanhanosaurus is its strong front limbs, which were more than 65 centimeters long. At first, scientists thought Xuanhanosaurus might have walked on all fours because of its big arms. If true, it would have been the only known meat-eating dinosaur to walk this way. However, many paleontologists now believe it actually walked on its two hind legs like other dinosaurs in its group.
Scientists classify Xuanhanosaurus within a larger family of dinosaurs called theropods, which are known for being meat-eaters.
Over the years, researchers have tried to understand where Xuanhanosaurus fits in the dinosaur family tree. It was initially thought to be part of a group called Megalosauridae, but later studies suggested it is more primitive within the Allosauroidea group, which includes many well-known dinosaurs like Allosaurus.
Overall, Xuanhanosaurus helps scientists learn about the diversity of dinosaurs during the Jurassic period and their evolution over millions of years.