Archaeornithomimus

Archaeornithomimus (meaning "ancient bird mimic") is a genus of ornithomimosaurian theropod dinosaur that lived during the Late Cretaceous period (around 96 million years ago) in the Iren Dabasu Formation of Inner Mongolia, China.

==Discovery and naming== thumb|left|Cervical vertebra (specimen AMNH FARB 21786) in multiple views In 1923, during the American Museum of Natural History expedition by Roy Chapman Andrews to Inner Mongolia, Peter Kaisen discovered numerous theropod remains in three quarries. They consist of the largely disarticulated remains of several individuals and material of the skull and the lower jaws is lacking. These were named and shortly described by Charles Whitney Gilmore in 1933 as a new species of Ornithomimus: Ornithomimus asiaticus. The specific name refers to the Asian provenance. The species was placed in the new genus Archaeornithomimus by Dale Russell in 1972, making Archaeornithomimus asiaticus the type species of the genus. The generic name combines that of Ornithomimus with a Greek ἀρχαῖος (archaios), "ancient", because Russell believed that the layers in which Archaeornithomimus was found dated to the Cenomanian-Turonian ages, about 95 million years ago, making it one of the oldest ornithomimids known at the time. Gilmore had not assigned a holotype specimen; in 1990, David Smith and Peter Galton in the first comprehensive description of the fossils, choose specimen AMNH 6565, a foot, as the lectotype. The fossils were found in the Iren Dabasu Formation, which has been dated to the Cenomanian age, around 95.8 ± 6.2 million years ago.