Trochosaurus

Trochosaurus (from , 'badger' and , 'lizard') is a dubious genus of therocephalian therapsid from South Africa, to which various species were once assigned. The genus was based upon multiple weathered and distorted fossils of therocephalians of the family Lycosuchidae. Like other lycosuchids, specimens placed in Trochosaurus have only five large incisors in each premaxilla, seemingly two functional "double canines" in each maxilla (of which the second was supposedly slightly larger in Trochosaurus), and few postcanines. However, the fossils lack any further diagnostic traits to justify referring them to their own genus, or to any species therein. Hence, Trochosaurus is now considered to be a nomen dubium (dubious name) and is disused, as are all its assigned species.

Trochosaurus was originally distinguished from other "double canined" therocephalians known at the time (Lycosuchus and Trochosuchus) only by the combination of Trochosuchus-like jaw proportions (shallower upper jaws and deeper lower jaws) with roughly equal-sized "double canines" as seen in Lycosuchus (unlike the smaller first canine described for Trochosuchus). However, such proportional differences are subject to distortion, and the variable size of lycosuchid canines is now recognised to only represent different stages of tooth growth and replacement. Furthermore, the poor condition of the fossils obscures any potentially useful diagnostic features, and so the specimens themselves can only be assigned to Lycosuchidae incertae sedis.