Xuanhanosaurus

*Xuanhanosaurus qilixianensis*

***Xuanhanosaurus*** (meaning "Xuanhan lizard") is a genus of theropod dinosaur which lived during the Jurassic of China.

The type species *Xuanhanosaurus qilixiaensis* was named by Dong Zhiming in 1984. The generic name refers to Xuanhan County in Sichuan. The specific name is derived from the town of Qilixia. The holotype specimen, IVPP V.6729, was found in China's Lower Shaximiao Formation, part of the Dashanpu Formation. It consists of a partial skeleton without skull.

## Description

*Xuanhanosaurus* was approximately 4.5 meters (15 ft) in length, with a weight of 250 kilograms (550 lb). *Xuanhanosaurus* had unusually long arms for a theropod, which were substantially reduced in later theropods such as *Tyrannosaurus rex*. Because of the powerful forelimbs, over two feet long, and the retention of the fourth metacarpal in the hand, Dong suggested that *Xuanhanosaurus* might have walked on all four legs. If so, it would be the only known four-legged meat-eater among dinosaurs.[1] Later paleontologists have not agreed with Dong's original assessment. They think this dinosaur walked on its hind legs as other theropods did, pronation of the lower arm being impossible. The strong arms could instead have been useful in catching prey.

Assigned by Dong to the Megalosauridae, *Xuanhanosaurus* was by Roger Benson in 2009 found to be a basal member of the Megalosauroidea.

Only the front limb and six primitive-looking vertebrae of this dinosaur have been discovered. But they are so different from other theropods that in 1984 Chinese paleontologist Dong Zhiming named the new genus **Xuanhanosaurus** after the type species, *Xuanhanosaurus quiliziansis*, for them.

Named after Xuanhan County Sichuan Basin where it was found, this theropod lived at the same time as the better-known theropod Gasosaurus, the stegosaur Huayangosaurus, and the sauropods Shunosaurus and Datousaurus. Dong at first classified Xuanhanosaurus in the family Megalosauridae, but Paleontologists now believe it requires its own family.

The arm of Xuanhanosaurus was about the same size as the arm of the later theropod Allosaurus, but it was more robustly built. The third finger was slender and it also probably had a claw but it was not found with a skeleton. A fourth finger was only a single small bone that was most likely imbedded in the palm of the hand and not visible in the living animal. It did not have a grasping hand. The shoulder bones and the breastbone were large, which suggests that Xuanhanosaurus sometimes used its arms for walking, similar to Spinosaurus.

Scientists are hoping to find more fossils of Xuanhanosaurus so They have more information to study. More fossils may also give clues as to which family this unusual dinosaur belongs to.

## JPInstitute.com Description

Xuanhanosaurus was a medium-sized predator that lived in China during the Jurassic Period. It had very long arms for a theropod and it may have walked on all four legs. This would have made it very unusual for a meat-eating dinosaur. Only a few bones have been found so it has been difficult for scientists to know exactly what this dinosaur really looked like.

## Appearance in other media

### *Jurassic Park*

* Xuanhanosaurus appeared in the Jurassic World toys.

## Links

https://web.archive.org/web/20080723235955/http://kids.yahoo.com/dinosaurs/430--Xuanhanosaurus