Proterosuchidae

Extinct family of reptiles

Proterosuchidae is an early family of basal archosauriforms whose fossils are known from the Late Permian and the Early Triassic. The highest diversity of genera is known from European Russia, but fossils are also known from South Africa, India, China, Australia, Brazil and possibly Argentina. ), long snouted and superficially crocodile like animals, although they lacked the armoured scutes of true crocodiles, and their skeletal features are much more primitive. The limbs are short and indicate a sprawling posture, like contemporary lizards but unlike most later archosaurs. Their most characteristic feature is a distinct down turning of the premaxilla (the front of the upper jaw, which overhangs the lower jaw).

The terminal Permian catastrophe, which killed off 95% of all types of life, cleared the world of all large therapsids and allowed the proterosuchids to become the top predators. Within the space of five million years the proterosuchids had evolved to fill a wide variety of terrestrial and semi aquatic niches. The proterosuchids represent perhaps the earliest adaptive radiation of the archosaurs. They gave rise to the Erythrosuchidae some time in the Early Triassic. A 2023 study recovered a majority of proterosuchids outside of Proterosuchus and Sarmatosuchus as belonging to a distinct subfamily, the Chasmatosuchinae. Chasmatosuchinae contains many Triassic proterosuchids in addition to the only Permian proterosuchid, Archosaurus; this would suggest that an initial taxonomic diversification of the Proterosuchidae (including an initial taxonomic divergence between Proterosuchus and chasmatosuchines) had already occurred in the Permian.