Tuojiangosaurus (meaning “Tuo River lizard”) is a genus of herbivorous stegosaurid dinosaur from the Late Jurassic Period, recovered from the Upper Shaximiao Formation of what is now Sichuan Province in China.
In 1974, during construction of the Wujiaba dam in Zigong, Sichuan, the remains of stegosaurians were found.
The type and only species of Tuojiangosaurus, Tuojiangosaurus multispinus, was named and described in 1977 (exactly a hundred years after the naming of Stegosaurus by Othniel Charles Marsh) by Dong Zhiming, Zhou Shiwu, Li Xuanmin and Chang Yijong. The generic name is derived from the River (jiāng) Tuo. The specific name is derived from Latin multus, “many”, and spina, “spine”.
The holotype, CV 209, was found in a layer of the Upper Shaximiao Formation, dating from the Oxfordian-Kimmeridgian. It consists of a rather complete skeleton that however lacks parts of the skull., lower jaws, tail and limbs. In 1977, it represented the most complete stegosaurian skeleton found in Asia. The paratype was specimen CV 210, a sacrum.
Subsequently, more material has been referred, including juveniles. This complemented the holotype with elements of the skull, especially the braincase, and the lower jaws.
A mounted skeleton of Tuojiangosaurus multispinus is on display at the Municipal Museum of Chongqing. In addition, a mounted cast is on display at the Natural History Museum, in London. Another mount is displayed in the Beijing Museum of Natural History in a conflict with Yangchuanosaurus. A cast of the original fossilised dinosaur skeleton, found at Wujiaba Quarry 1977 is also on display at Bolton Museum, United Kingdom.
Physically similar to the North American Stegosaurus, Tuojiangosaurus is the best understood of the Chinese stegosaurids. It was around 7 metres (23 ft) long and 2 metres (6.6 ft) high. In 2010, Gregory S. Paul estimated the weight of a 6.5 metre long Tuojiangosaurus at 2.8 tonnes.
In 1977, Dong provided a diagnosis but this largely consisted of traits shared with other stegosaurs. In 1990, Peter Malcolm Galton pointed out an autapomorphy: the spines of the vertebrae of the tail base possess spines with bony skirts running from their front to the sides.