rauisuchids

Rauisuchids were a diverse group of large, predatory archosaurs that lived during the Triassic period. They are often referred to as "rauisuchians" or "crurotarsans," though the term crurotarsan is now more broadly applied to the entire group of pseudosuchians which includes rauisuchids. These animals were among the dominant terrestrial carnivores of their time, filling ecological niches similar to those later occupied by theropod dinosaurs.

Rauisuchids possessed a wide range of body plans and sizes, with some species reaching lengths of over 6 meters. They typically had robust bodies, strong limbs, and powerful jaws filled with sharp teeth. Many rauisuchids were bipedal, but some may have been facultative bipeds, capable of walking on four legs as well. Their locomotion was characterized by an erect stance, with limbs held directly beneath the body, unlike the sprawling posture of many other reptiles.

The taxonomic classification of rauisuchids has undergone revisions over time. Traditionally placed within the order Rauisuchia, they are now generally considered to be a monophyletic group within the infraorder Loricata, which also includes crocodiles and their extinct relatives. Fossil evidence for rauisuchids has been found on several continents, indicating a widespread distribution throughout the Triassic. Their extinction at the end of the Triassic period coincided with the rise of dinosaurs, which would go on to dominate terrestrial ecosystems in the Jurassic and Cretaceous periods.