Temporal range: Late Jurassic, 160.1 Ma
Holotype specimen
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Superfamily: Alvarezsauroidea
Genus: Haplocheirus
Choiniere et al., 2010
Type species
Haplocheirus sollers
Choiniere et al., 2010
Size of Haplocheirus compared to a human.

Haplocheirus is a genus of alvarezsauroid theropod dinosaur. It is the oldest known alvarezsauroid, predating all other members by about 63 million years.[1] 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.[2] The type species is H. sollers, meaning "simple-handed skillful one", referencing its hypothesized behavior of using its three-fingered hands for activities that other alvarezsauroids could not perform, such as catching prey.[1][3]


Life restoration.

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.

See also


  1. ^ a b Choiniere, J. N.; Xu, X.; Clark, J. M.; Forster, C. A.; Guo, Y.; Han, F. (2010). "A basal alvarezsauroid theropod from the Early Late Jurassic of Xinjiang, China". Science. 327 (5965): 571–574. doi:10.1126/science.1182143. PMID 20110503.
  2. ^ Qin, Zichuan; Clark, James; Choinere, Jonah; Xu, Xing (2019). "A new alvarezsaurian theropod from the Upper Jurassic Shishugou Formation of western China". Scientific Reports. 9 (1): 11727. doi:10.1038/s41598-019-48148-7. PMC 6692367. PMID 31409823.
  3. ^ Choiniere, J. (2010). Guest Post: Haplocheirus, the Skillful One Dave Hone's Archosaur Musings, April 23, 2011.

External links

  • Richard Stone Bird-Dinosaur Link Firmed Up, And in Brilliant Technicolor Science 29 January 2010: Vol. 327. no. 5965, p. 508, DOI 10.1126/science.327.5965.508
  • Doreen Walton New dinosaur discovery solves evolutionary bird puzzle BBC News Thursday, 28 January 2010