Once believed to have been an ancestor to lizards, Protorosaurus is now known to be one of the oldest and most primitive members of Archosauromorpha, the group that would eventually lead to archosaurs such as crocodilians and dinosaurs.

[3] Over a century later, in publications in 1830 and 1832 Hermann von Meyer recognised Protorosaurus as distinct extinct reptile and gave it a formal species description, dedicating an extensive monograph to it in 1856.

[2] Stomach contents of a specimen of Protorosaurus show the presence of numerous ovules of the locally common voltzialean conifer Ullmannia frumentaria, which was unexpected given its unspecialised dentiton of conical and unserrated teeth, which were assumed to represent a predatory lifestyle.

The terrestrial flora of the Zechstein is dominated by conifers, with seed ferns also being common, while taeniopterids, ginkgophytes and sphenophytes are rare.

Other terrestrial vertebrates found in the Kupfershiefer and lower Zechstein include the gliding weigeltisaurid reptiles Weigeltisaurus and Glaurung, the pareiasaur Parasaurus, the cynodont Procynosuchus, and indeterminate captorhinids, dicynodonts, and dissorophid temnospondyls.