The holotype fossil of Zuolong, IVPP V15912, a partial skeleton with skull, was discovered in 2001 in China, in the upper part of the Shishugou Formation of Xinjiang. It was a subadult animal which measured approximately 3.1 metres (10 ft) in length and weighed up to approximately 35 kilograms (77 lb). Zuolong was named by Jonah N. Choiniere, James M. Clark, Catherine A. Forster and Xu Xing in 2010, and the type species is Zuolong salleei. The generic name honours General Zuo Zongtang, who secured Xinjiang for China in the nineteenth century. The specific name honours Hilmar Sallee, whose bequest helped finance the research.[1] The specific age for the holotype specimen is 161.2 to 155.2 million years ago. The holotype is considered by Thomas R. Holtz Jr. to be from almost certainly a juve