Inostrancevia alexandri — a mammal-like reptile
Inostrancevia was a mammal-like reptile. During the Permian period, before the time of the first dinosaurs, the dominant land animals were the mammal-like reptiles. These were specialised reptiles, with some features of mammals.
Inostrancevia was one of the largest predators of its time. It had a deep skull, nostrils set high on its head and large, sabre-like canine teeth. Its back teeth were small and weak, but this didn’t matter because Inostrancevia didn’t chew its food. It could rip into its prey and swallow large chunks of meat, as its lower jaw was hinged to allow its mouth to open very wide. Inostrancevia had a semi-sprawling gait making it a more efficient runner than other reptiles of its time, but not as fast as modern predators such as lions.
Many of the mammal-like reptiles died out at the end of the Permian period, when more than 80% of all life on Earth became extinct. But some survived the extinction event, and some of those mammal-like reptiles eventually gave rise to modern mammals.