Temporal range: Late Permian, 265–251Ma
|Life restoration of A. rossicus|
Archosaurus is an early genus of proterosuchid archosauromorph, previously believed to have been an archosaur, found in Middle and Late Permian deposits of Poland and Russia (265 million to 251 million years ago). Archosaurus typifies the progressive changes occurring in reptilian structure that eventually led to their dominance as the major vertebrates. A clear trend was in the modification of the limbs and the pelvis. The type, and only species, is Archosaurus rossicus, known from several fragmentary specimens which, if compiled, represent parts of the skull and cervical vertebrae set.
- PIN Nr1100/55, left premaxilla (holotype)
- Pin 1100/66, three cervical vertebrae
- PIN 100/84, a substantial part of the left side of the skull roof
- PIN 1100/84a, an incomplete right squamosal
- PIN 1100/78, left dentary