Erlikosaurus were therizinosaurs, a strange group of theropods that ate plants instead of meat, and that had backward-facing pubises like ornithischians. Also like ornithischians, their jaws were tipped by a broad rounded bony beak useful for cropping off plants. Behind the beak, separated by an hiatus, there were per side twenty-three small straight coarsely serrated teeth in the maxilla. The dentary of the lower jaw had more teeth: thirty-one for a total of one hundred eight. The bony nostrils of Erlikosaurus were very large and elongated. The braincase was swollen at the back by pneumatised bone. Scientists now know some therizinosaurs were feathered, so it is likely that Erlikosaurus were as well. Erlikosaurus had exceptionally long slender claws on their feet, with a bone core of up to ten centimetres, the purpose of which is unclear; G.S. Paul surmised they were used for self-defence.
As the genus is only known from very fragmentary material, it has been problematic to determine the size of Erlikosaurus, especially as most of the vertebral column of the holotype is missing. The skull length is twenty-five centimetres; the humerus is thirty centimetres long. It has been estimated to attain an adult body length of six meters (twenty feet). Erlikosaurus may have been more lightly built than close relative Segnosaurus. Other estimates are lower: in 2010 Gregory S. Paul gave a length of 4.5 metres and a weight of half a tonne.
Popular in CultureEdit
In The Land Before Time XI: Invasion of the Tinysauruses, a pair of green Erlikosaurus appear during a crowd shot near the end of the film. They are green in color, with blue stripes and a peach underbelly; an identical color scheme to the Rainbow Faces, which appear earlier in the film. It is very likely that the creatures in The Land Before Time are the result of an error on the part of the animators, where what were originally intended to be Rainbow Faces were erroneously drawn as Fast Biters, and were later colored as their intended species to attempt to make up for the mistake.