Jiangjunosaurus is a genus of herbivorous stegosaurian dinosaur from the Oxfordian-age (Upper Jurassic) Shishugou Formation of the Junggar Basin, Xinjiang, China.
In 2002, Liu Yongfei discovered the remains of a stegosaurian. These were secured by a Sino-American expedition and prepared by Xiang Lishi and Ding Xiaoqing.[1]
The type species, Jiangjunosaurus junggarensis, was named and described by Jia Chengkai, Catherine Foster, Xu Xing and James Clark in 2007. The generic name refers to the abandoned town of Jiangjunmiao. Jiangjun, 將 軍, is "general" in Chinese and the town's name, the "temple of the general", has been explained by the burial of one. The specific name refers to the provenance from the Junggar.[1]
The holotype, IVPP V 14724, was found in a layer of the Shishugou Formation, dating from the Oxfordian. It includes the lower jaws, some rear skull bones, eleven neck vertebrae, ribs, a scapula, a coracoid, and two neck plates. These elements were found in almost perfect articulation. It represents a subadult individual.[1]
Jiangjunosaurus was a medium-sized stegosaur, reaching 6 metres (20 ft) in length and 2.5 metric tons (2.8 short tons) in body mass.[2] The describers established three distinguishing traits: the crowns of the teeth are symmetrical and in side view wider than tall; the spine of the axis, the second neck vertebra, has a rectangular profile in side view, instead of a triangular one; and the rear neck vertebrae have large vein openings in their sides.[1]
The skull of Jiangjunosaurus is relatively elongated, the maximum width above the postorbitals probably measuring 35% of the skull length. There are at least fourteen teeth in the maxilla. The quadratojugal has a robust horizontal front branch and a thin short vertical branch, only half as tall as the quadrate shaft. There is no clear foramen paraquadraticum, opening between the quadrate and quadratojugal. The quadrate is inclined to the rear and has a depression on its flange contacting the pterygoid. There is no clear opening between the front branches of the pterygoids.[1]