Its fossilized remains have been found in the Fremouw Formation of Antarctica and Australia.

The holotype of the partial skull shows evidence of promiment upper and lower canine teeth.

The name was coined by Edwin Harris Colbert and James William Kitching, who described the species in 1981 based on a fossil found in 1970-1971.

[2] Modern paleontologists such as Christian Sidor consider the species a nomen dubium.

Sidor describes it as an "indeterminate juvenile baurioid" and suggests that the name Rhigosaurus be discontinued.