Avimimus ‭(‬bird mimic‭)

Short Info

Avimimus ‭(‬bird mimic‭)

Phonetic : A-vee-mi-mus.

Named By : Sergei Kurzanov‭ ‬-‭ ‬1981

Diet : Carnivore/ Possibly Omnivore or Insectivore

Size : Estimated 1.5 meters long

Type of Dinosaur : Small Theropod

Type Species : A.‭ ‬portentosus‭ (‬type‭), A. nemegtensis

Found in : China, Mongolia‭ ‬-‭ ‬Nemegt Formation

When it Lived : Late Cretaceous, 80-75 million years ago

Avimimus (/,eIvI’maIm@sor AY-vi’m@s) is a Latin word meaning “bird mimic” (Latin avis = mimus and bird is a synonym for mimic) is a genus in the Theropod dinosaurs from the oviraptorosaurian genus, because of its bird-like features which were observed in the Cretaceous of the late Cretaceous, in the area that is now Mongolia between 85 and 70 million years ago.

Avimimus skeleton
★Kumiko★, CC BY-SA 2.0, via Wikimedia Commons

Avimimus was a small bird-like dinosaur, with the length of 1.5 meters (5 5 feet). The skull was small in comparison to the human body, however the eyes and the brain were huge. The bones that surround the head and devoted to protect it were huge. This is in accordance with the idea that Avimimus was a person with a larger than average brain.

The jaws on Avimimus were believed to have formed the shape of a parrot’s beak, without teeth. A thorough study of the holotype’s anatomy proved that no teeth had been preserved, however a set of tooth-like projections on the edge of the premaxilla were. However, later discovered specimens were found to have preserved small premaxillary teeth. The tiny teeth or the possible absence of teeth present in Avimimus indicates that the animal might have been an herbivore , or an omnivore. Kurzanov himself believed that Avimimus was an insectivore.

The foramen magnum, which is the opening that allows your spinal cord join the skull, appeared a significant size in Avimimus. The occipital cone, however, was tiny and further hints at the skull’s lightness. The neck was also slim and long and is made up of vertebrae that are larger than the ones found in other oviraptorosaurs. In contrast to caenagnathids and oviraptorids, the vertebrae of the back lack openings for air sacs which suggests it is possible that Avimimus has a lower level of development than other species.

The forelimbs were quite small. Hand bones were bonded together, just like modern birds. A groove in the ulna (lower arm bone) was believed to be an anchor point to feathers according to Kurzanov. Kurzanov in 1987 also mentioned the existence of quill knobs and even though Chiappe confirmed the existence that there were bumps in the ulna their purpose was not clear. Kurzanov was convinced they were the attachment points to feathers that he thought that Avimimus might be capable of flying weakly. The existence of feathers is currently generally accepted, however the majority of paleontologists are skeptical that Avimimus could fly.

The ilium was nearly horizontally oriented, leading to extremely wide hips. There isn’t much information about the tail, but the hips suggest it was very long. The legs were exceptionally slim and long and thin, suggesting the possibility that Avimimus was a very specialized athlete. Aspects in the bones in the legs give further support to the theory that Avimimus was swift to its feet. The animal’s shins had a long length when compared to the thighs, a feature that is common to cursorial animals. The animal also had three-toed feet, with pointed claws that were narrow.

It is believed that the remains of Avimimus were discovered by Russian paleontologists, and then officially recorded in the work of Dr. Sergei Kurzanov in 1981. These Avimimus fossils were first identified as being in the Djadokta Formation by Kurzanov; However, in a 2006 description of a newly discovered specimen Watabe and coworkers noted that Kurzanov was most likely wrong regarding the source and that there is a higher likelihood that Avimimus was a part of older Nemegt Formation. The species of interest that is the most common species A. portentosus. Since no tail was discovered in the initial find and the species was not found, Kurzanov incorrectly believed that Avimimus did not have a tail in its the past. However, subsequent discoveries of Avimimus that contain caudal vertebrae confirm that there is an actual tail. A second almost complete specimen of the Avimimus was discovered in 1996 and was described at the time of 2000 by Watabe coworkers. Furthermore, they identified several small footprints of theropods in the same area that belong to Avimimus.

A number of bones that were attributed to Avimimus were thought as distinct in comparison to A. portentosus. They were initially identified in the form of Avimimus SP. Then, in 2008, a group consisting of Canadian, American, and Mongolian paleontologists led by Phil Currie reported in 2006 an extensive bone bed consisting of Avimimus sp. fossils. The bonebed is found in the Nemegt Formation, 10.5 meters above the Barun Goyot Formation within the Gobi Desert. The team found numerous bones from at least 10 individuals of Avimimus however, the deposit could contain more. The majority of the individuals were adult or subadult, and adults had little variation in size, which suggests that they had a consistent growth. The research team suggests that the individuals were placed close because they were social throughout their lives, providing an indication that Avimimus created age-segregated groups for reasons of flocking or lekking. Adults showed a higher amount of skeletal fusion the tibiotarsus as well as the tarsometatarsus as well as more noticeable scars on the muscles. The bonebeds’ preservation suggests that they were submerged quickly, then exposed by a rapid flows of water, and later, buried just a small distance away. In 2018, Avimimus sp. was officially identified as a novel species, A. Nemegtensis.

Avimimus was first believed to be a closely related bird to the birds due to its unique set of birds-like characteristics not seen in other dinosaurs of the day. In reality, Kurzanov claimed that Avimimus was, not the well-known early bird Archaeopteryx was the closest ancestor of modern birds and Archaeopteryx wasn’t so closely connected to birds as had been previously suggested. But this notion is not supported by the phylogenetic analysis of bird and dinosaur relationships. Modern scientists have concluded that Avimimus actually belongs to the bird-like group, which includes dinosaurs that are more primitive than Archaeopteryx and the oviraptorosaurs.

Kurzanov put Avimimus within it’s own group, Avimimidae, in 1981. It was in the year 1991 that Sankar Chatterjee erected the Order Avimimiformes to include Avimimus. None of these names is often used by paleontologists since they encompass only one species. Recent research has shown the fact that Avimimus is best placed within the Oviraptoridae and within the subgroup Elmisaurinae.

Source: Wikipedia