Wuerhosaurus is a genus of stegosaurid dinosaur from the Early Cretaceous Period of what is now China. It was one of the last genera of stegosaurs known to survive, since most others died out during the Late Jurassic Period.
The type species, W. homheni, was described by Dong Zhiming in 1973 from the Tugulu Group in Xinjiang, western China. The specimen is known from a fragmentary skeleton lacking a skull. A second individual, W. ordosensis, which was found in the Ejinhoro Formation in the Ordos Basin in Inner Mongolia, and was described by the same researcher in 1993, consisted of fossil fragments including part of the tail bone.
In 2008, Susannah Maidment and colleagues proposed that Wuerhosaurus should be considered a junior synonym of Stegosaurus, thus changing the type species to S. homheni, and the second specimen to S. ordosensis.
Wuerhosaurus is thought to have been a broad bodied animal close to 20 feet long, but since only a few fragmentary bones have been found, making a full restoration is difficult. Its dorsal plates were much rounder than other stegosaurids. It stood lower to the ground than most other stegosaurids. Scientists theorize that this would have been adaptation to let it feed on low-growing vegetation. Like other stegosaurids, Wuerhosaurus had a thagomizer on the end of its tail, which featured four bony spikes most likely used for self defense.