Bones in the back of the skull called parietals are enlarged, indicating that it may have had larger jaw muscles and a stronger bite than most monitor lizards.

The nostrils have expanded and moved backward in later varanoids, separating the maxilla and nasal bone.

The teeth of Proplatynotia are smooth and lack plicidentine, folded layers of dentine around the center pulp cavity of the tooth.

Plicidentine, while rare in land-living vertebrates, is characteristic of monitor lizards and their closest extinct relatives.

In most recent studies, Platynotia includes monitor lizards, helodermatids, and their close extinct relatives, but not snakes.