Before the Great Permian Extinction wiped out 95% of life on the planet, Archosaurs (Ancient Lizards) held sway over the land. Postosuchus was the last giant example of this animal type to evolve, late in the Triassic, though its descendants live on today in the modern crocodile. The more upright gait of Postosuchus made him a more efficient runner, giving him the edge over slower predators with more sprawling gaits.
