In 2010, Gregory S. Paul challenged the validity of this taxon, arguing that "Erlikosaurus" may be synonymous with "Enigmosaurus" (named in 1983), since the remains of the latter were found in the same geologic formation, and only known from pelvic remains, whereas the pelvis in "Erlikosaurus" is unknown; this would make "Enigmosaurus" a junior synonym of "Erlikosaurus". However, since the holotype hip of "Enigmosaurus" did not closely resemble that of the specimen in "Segnosaurus" as would be expected for the "Segnosaurus"-like remains of "Erlikosaurus", and there is a considerable size difference, paleontologist Rinchen Barsbold disputed the alleged synonymy. Additional to this, the remains of "Erlikosaurus" and "Enigmosaurus" are known from upper and lower boundary, respectively. Consequently, "Enigmosaurus" and "Erlikosaurus" are generally considered separated genera.