The amphibians and earliest reptiles that evolved from them are often referred to as cotylosaurs, and the stem reptiles themselves are called captorhinomorphs. Less than 100 million years after their first appearance, the captorhinomorphs had already divided into three major divisions (Subclasses) based on the skull structure.
Why go to the Permian?
The interlude of four days north of Agadez gave us a chance to assist Chris Sidor, who is interested in vertebrates of the Permian. These include the famous "pelycosaurs," the sail-backed reptiles often misconstrued as dinosaurs, and other groups of reptiles and amphibians.
The Permian world-remarkable for its mammal-like reptiles and enormous predatory amphibians-would have looked very different than the later dinosaur era. There were no dinosaurs, birds, pterosaurs, turtles or crocodiles. Instead, a host of different reptiles abounded, like the captorhinomorphs that look sort of like a cross between a lizard and a crocodile.
The Permian is the age that directly precedes the Triassic, the first chapter in dinosaur evolution. One of the greatest extinction episodes ever to affect the planet occurred at the end of the Permian and gave dinosaurs and other plants and animals a chance to flourish.