Hesperornithoides ("Western bird form") is a genus of troodontid from the Late Jurassic Morrison Formation of North America. It is the only known troodontid from the Jurassic and the smallest known dinosaur from the Morrison Formation. It was originally discovered in 2001 in the Jimbo Quarry next to the eponymous holotype of Supersaurus. The fossil was nicknamed "Lori" after one of the paleontologists who discovered it. It was described and given its name in 2019. Its existence is a strong refutation of the temporal paradox used to argue against the hypothesis that birds evolved from dinosaurs, as it is a dinosaur with bird-like features that existed before the evolution of more advanced birds.
Discovery[]
In 2001, a field crew from the Tate Museum supervised by William Wahl unexpectedly discovered the fossil in rocks of the Jimbo Quarry of the Morrison Formation, overlying the excavation site of Supersaurus vivianae, near Douglas, Wyoming.
