Haplocheirus

Haplocheirus Temporal range: Late Jurassic, 160 Ma PreЄ Є O S D C P T J K Pg N ↓
Holotype specimen
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Dinosauria
Order:	Saurischia
Suborder:	Theropoda
Genus:	†Haplocheirus Choiniere et al., 2010
Species:	†H. sollers
Binomial name
Haplocheirus sollers Choiniere et al., 2010

Haplocheirus is a genus of alvarezsauroid theropod dinosaur. It is the earliest member of its clade. It is the oldest known alvarezsauroid, predating all other members by about 63 million years. This also makes it about 15 million years older than Archaeopteryx. Haplocheirus was described in 2010 from a fossil specimen found from the 160-million-year-old Shishugou Formation in the Junggar Basin of northwestern China. The type species is H. sollers, meaning "simple-handed skillful one", referencing its hypothesized behavior of using its three-fingered hands for activities other alvarezsauroids couldn't, such as catching prey.

Haplocheirus was the largest known definite alvarezsauroid, at around 2 meters long. It had an enlarged thumb claw like other alvarezsauroids, but also retained two other functional fingers, unlike more derived alvarezsauroids, where only the thumb was significantly large and clawed. It had long legs and was probably a fast runner.