Xuanhanosaurus

XUANHANOSAURUS (zoo-ahn-HAN-oh-SORE-us)

Period: Middle Jurassic

Order, Suborder, Family: Saurischia, Theropoda, Unknown

Location: Asia (People's Republic of China)

Length: 20 feet (6 meters)

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 a new genus and species, Xuanhanosaurus qilixiaensis, for them.

Named after Xuanhan County in the 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 first two fingers were large and thick and had prominent claws. The third finger was slender and it also probably had a claw, but it was not found with the 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.

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.