several rounded pebbles were found in the body cavity, these may have functioned as gastroliths. Relationships Protorosaurus has been suggested to be closely related to Czatkowiella from the Early Triassic of Poland, but the remains of Czatkowiella are fragmentary and mixed in with those of other reptiles, so it is possible that the taxon is a chimaera. In a comprehensive analysis of "Protorosauria" in 2021, Protorosaurus was consistently recovered as the earliest diverging member of Archosauromorpha. The cladogram below follows an analysis by Ezcurra (2016), and highlights the position of Protorosaurus among other early archosauromorph reptiles. Paleoenvironment The Kupferschiefer and equivalent Marl Slate is a marine unit that forms part of the Zechstein, a sequence of rocks formed on the edge of the Zechstein Sea, a large inland shallow sea that existed in Northern Europe during the Late Permian. The environment at the time of deposition is considered to have been semi-arid. 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. References Prehistoric reptile genera Lopingian life Prehistoric archosauromorphs Permian reptiles of Europe Permian Germany Fossils of Germany Kupferschiefer Fossil taxa described in 1830 Taxa named by Christian Erich Hermann von Meyer