The remains of Avimimus were recovered by Russian paleontologists and officially described by Dr. Sergei Kurzanov in 1981.
The Avimimus fossils were initially described as having come from the Djadokta Formation by Kurzanov; however, in a 2006 description of a new specimen, Watabe and colleagues noted that Kurzanov was probably mistaken about the provenance, and it is more likely that Avimimus hailed from the more recent Nemegt Formation.
The type species is A. portentosus.
Because no tail was found with the original find, Kurzanov mistakenly concluded that Avimimus lacked a tail in life.
However, subsequent Avimimus finds containing caudal vertebrae have confirmed the presence of a tail.
A second nearly complete specimen of Avimimus was discovered in 1996 and described in 2000 by Watabe and colleagues.
Additionally, these authors identified a number of small theropod footprints in the same area as belonging to Avimimus.

A variety of isolated bones that have been attributed to Avimimus were considered to be distinct from A. portentosus, and were initially referred to as Avimimus sp.
In 2008, a team of Canadian, American, and Mongolian paleontologists headed by Phil Currie reported the 2006 an extensive bonebed of Avimimus sp.
fossils, discovered in 2006.
The bonebed is in the Nemegt Formation, 10.5 meters above the Barun Goyot Formation, in the Gobi Desert.
The team reported finding abundant bones of at least ten individuals of Avimimus, but the deposit may hold more.
All individuals were either adult or subadult, and the adults showed little variation in size, suggesting determinate growth.
The team also suggests that the individuals were found together because they were gregarious in life, providing possible indications that Avimimus formed age-segregated groups for either lekking or flocking purposes.
The adults showed a greater degree of skeletal fusion in the tarsometatarsus and tibiotarsus, and also more prominent muscle scars.
The preservation of the bonebeds suggest that they were buried rapidly, uncovered by rapid flow of water, and then buried again a short distance away.
In 2018, Avimimus sp.
was formally described as a new species, A. nemegtensis.
The remains of Avimimus were recovered by Russian paleontologists and officially described by Dr. Sergei Kurzanov in 1981. The Avimimus fossils were initially described as having come from the Djadokta Formation by Kurzanov; however, in a 2006 description of a new specimen, Watabe and colleagues noted that Kurzanov was probably mistaken about the provenance, and it is more likely that Avimimus hailed from the more recent Nemegt Formation. The type species is A. portentosus. Because no tail was found with the original find, Kurzanov mistakenly concluded that Avimimus lacked a tail in life. However, subsequent Avimimus finds containing caudal vertebrae have confirmed the presence of a tail. A second nearly complete specimen of Avimimus was discovered in 1996 and described in 2000 by Watabe and colleagues. Additionally, these authors identified a number of small theropod footprints in the same area as belonging to Avimimus.
A variety of isolated bones that have been attributed to Avimimus were considered to be distinct from A. portentosus, and were initially referred to as Avimimus sp. In 2008, a team of Canadian, American, and Mongolian paleontologists headed by Phil Currie reported the 2006 an extensive bonebed of Avimimus sp. fossils, discovered in 2006. The bonebed is in the Nemegt Formation, 10.5 meters above the Barun Goyot Formation, in the Gobi Desert. The team reported finding abundant bones of at least ten individuals of Avimimus, but the deposit may hold more. All individuals were either adult or subadult, and the adults showed little variation in size, suggesting determinate growth. The team also suggests that the individuals were found together because they were gregarious in life, providing possible indications that Avimimus formed age-segregated groups for either lekking or flocking purposes. The adults showed a greater degree of skeletal fusion in the tarsometatarsus and tibiotarsus, and also more prominent muscle scars. The preservation of the bonebeds suggest that they were buried rapidly, uncovered by rapid flow of water, and then buried again a short distance away. In 2018, Avimimus sp. was formally described as a new species, A. nemegtensis.
Avimimus