Hesperornithoides

Hesperornithoides is a troodontid theropod dinosaur from the Upper Jurassic Morrison Formation of western North America. 

Discovery
The fossil was found in Wyoming, as the site was carefully documented by the collectors.Lovelace D.M. 2006. An Upper Jurassic Morrison Formation fire-induced debris flow: taphonomy and paleoenvironment of a sauropod (Sauropoda: Supersaurus vivianae) locality, east-central Wyoming. pp. 47–56. In: Foster J.R. and Lucas S.G. (eds) Paleontology and geology of the Upper Jurassic Morrison Formation. New Mexico Museum of Natural History and Science Bulletin 36.

Classification
A phylogenetic analysis was presented in an abstract in the Journal of Vertebrate Paleontology in 2005. The analysis decided the specimen was a close relative of Sinornithoides.Hartman S; Lovelace D. and Wahl W. 2005. Phylogenetic assessment of a maniraptoran from the Morrison Formation. Journal of Vertebrate Paleontology, 25, Supplement to #3, pp 67A-68A  

Significance
This dinosaur is very significant because it is the oldest known troodontid from North America. Until the discovery of Lori, troodontids were believed to have first originated and evolved in Asia and then migrated to North America. Most troodontids were discovered in Asia, and the previously oldest known troodontids, from the Lower Cretaceous, lived there.Hartman, Scott; Mortimer, Mickey; Wahl, William R.; Lomax, Dean R.; Lippincott, Jessica; Lovelace, David M. (2019). A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7: e7247. doi:10.7717/peerj.7247. 

 References 

Category:Theropods
Category:Fossils
Category:Jurassic dinosaurs