Tugulusaurus (meaning "Tugulu lizard") is a genus of coelurosaurian theropod dinosaur that possibly belongs to the Alvarezsauria. It is known from the Early Cretaceous Tugulu Group in the Urhe area of the People's Republic of China.
From 1964 dinosaur fossils were excavated in the Junggar Basin of Xinjiang. In 1973 a number of these were described by paleontologist Dong Zhiming, among them the bones of a small theropod which he named Tugulusaurus faciles. The generic name refers to the Tugulu Group. The specific name is derived from Latin facilis, here with the meaning of "easily moving", referring to the agility of the animal as indicated by its "delicate bones".
The holotype, IVPP V4025, was found in layers of the Lianmuqin Formation dating from the Barremian–Albian. It consists of a partial skeleton including four partial tail vertebrae, much of the left leg and part of the right, the first fingers of both hands, and a rib. The femur has a length of about 215 millimetres (8.5 in). The left first metacarpal is very short: 26 millimetres (1.0 in). The skeleton represents the only remains of the species that have ever been discovered.
Tugulusaurus was originally classified by Dong in 1973 as a member of the Ornithomimidae, within the Coelurosauria. In the years that followed, the genus was often considered a nomen dubium. However, in 2005 Oliver Rauhut and Xu Xing concluded that it is a valid genus of basal coelurosaurian of unknown affinities. In their cladistic analysis of the newly described taxa Bannykus and Xiyunykus, Xu et al. (2018) recovered Tugulusaurus as a member of Alvarezsauria.
- Dong, Z.-M. 1973. [Dinosaurs from Wuerho]. Memoirs of the Institute of Vertebrate Paleontology and Paleoanthropology, Academia Sinica 11: 45–52 [Chinese]
- Rauhut, Oliver W.M.; Xu, Xing (2005). "The small theropod dinosaurs Tugulusaurus and Phaedrolosaurus from the Early Cretaceous of Xinjiang, China". Journal of Vertebrate Paleontology. 25 (1): 107–118. doi:10.1671/0272-4634(2005)025[0107:TSTDTA]2.0.CO;2.
- Dong Zhiming (1992). Dinosaurian Faunas of China. China Ocean Press, Beijing. ISBN 978-3-540-52084-9.
- Norman, D. B. (1990). "Problematic Theropoda: Coelurosaurs". 280-305 in Weishampel, D. B., Dodson, P., & Osmólska, H. (eds.) The Dinosauria. Berkeley: University of California Press, Berkeley 1990, xvi-733
- Xing Xu; Jonah Choiniere; Qingwei Tan; Roger B.J. Benson; James Clark; Corwin Sullivan; Qi Zhao; Fenglu Han; Qingyu Ma; Yiming He; Shuo Wang; Hai Xing; Lin Tan (2018). "Two Early Cretaceous fossils document transitional stages in alvarezsaurian dinosaur evolution". Current Biology. Online edition. doi:10.1016/j.cub.2018.07.057.