Avimimus, meaning “bird mimic”, is a genus of bird-like maniraptorian dinosaur of the Late Cretaceous Period (70 million years ago) that lived in what is now Mongolia. Its name is derived from the Latin words avis: “bird”, and mimus: “mimic”. The remains of Avimimus were discovered by Russian paleontologists and described by Dr. Sergei Kurzanov in 1981. The initial description of Avimimus placed it in the Djadokta Formation by Kurzanov; however, in 2006 some scientists believed Kurzanov was mistaken and that Avimimus actually hailed from the more recent Nemegt Formation. The type species is A. portentosus.
During recovery, Kurzanov found no tail fossils and concluded that Avimimus had no tail in life; however, recent Avimimus fossil finds show that it did in fact have a tail. A second nearly complete specimen was recovered in 1996 and described in 2000 by Watabe and his colleagues. IN 2008, a team of paleontologists discovered an extensive bonebed of Avimimus in the Nemegt Formation, 35 feet above the Barun Goyot Formation in the Gobi Desert. At least 10 individuals were reportedly found, and possibly more could be found. The team, made up of American and Canadian paleontologists, speculated that the reason for so many individuals to be found in one area is that they were most likely gregarious.
Avimimus was a small dinosaur that was most likely 5 feet in length. The skull was small compared to the body, though it had large eyes and a large brain. The jaws of the Avimimus formed a parrot-like beak, and lacked teeth. It did have tooth-like projections along the upper jaw that appeared to have serrated edges. It is suggested, due to the lack of teeth, that Avimimus was a herbivore or possible omnivore. Kurzanov believed that it was actually an insectivore.
The hole at the base of the skull that connected the spinal cord to the brain was particularly large. The neck was long and slender, and was composed of longer vertebrae than in other oviraptorosaurs. The back vertebrae lacked openings for air sacs, suggesting it was more primitive than other oviraptorosaurs. Its forelimbs were short and the hand bones were fused together, as in modern birds. The ridge located on the ulna (lower arm bone) was interpreted as an attachment point for feathers. The function of bumps also located along the ulna remains unclear.