The teeth were typical of advanced cynodonts, and the animal was probably a carnivore hunting reptiles and other small prey.

[1] Prozostrodon brasiliensis was originally described as a species of Thrinaxodon in a 1987 paper by Mário C. Barberena, José F. Bonaparte and A. M. Sá Teixeira.

[2] The holotype (UFRGS-PV-0248-T) includes a well-preserved skull preserving the front half of the cranium, a mostly complete lower jaw and all of the teeth, but missing most of the braincase, sagittal crest and zygomatic arches.

It also preserves multiple postcranial elements, including parts of the vertebral column, ribs, interclavicle, humeri, right ilium, femora and right foot.

[1] A 2001 redescription by Bonaparte & Barberena indicated that T. brasiliensis was indeed more closely related to mammals than to the other Thrinaxodon species; as a result, it was reclassified into the new genus Prozostrodon.

[7] With the holotype having an estimated skull length of 6.7 centimetres (2.6 in), Prozostrodon was considerably larger than the other prozostrodontians (Alemoatherium and Therioherpeton) from its locality.

The postorbital bar, which had divided the eye socket from the temporal fenestra in earlier cynodonts, was missing in Prozostrodon, as in most other prozostrodontians.

On the lingual (inner) side of the upper postcanines, there was a deep groove where the lower teeth would have fit when the mouth was closed.

At the rear end of the dentary, behind the tooth row, a somewhat tall and broad coronoid process extended upwards.

[1][3] Like most cynodonts, Prozostrodon had a heterodont dentition divided into incisors, canines and postcanines (cheek teeth).

[11] A 2023 phylogenetic analysis recovered Prozostrodon as the sister taxon of Pseudotherium, a prozostrodontian from the Carnian Ischigualasto Formation of Argentina.

The clade formed by the two genera was named Prozostrodontidae:[7] Lumkuia Chiniquodon Probainognathidae Ecteniniidae Protheriodon Prozostrodon Pseudotherium Therioherpeton Irajatherium Riograndia Diarthrognathus Pachygenelus Tritylodontidae Botucaraitherium Brasilodon Mammaliaformes