Archosaurs translated in greek means, ruling lizards. They are a group of diapsid that are believed to be the first evolved from [[Archosauriform]s during the lower triassic period. They are set apart by socketed teeth and having the most traits similiar to modern birds and crocodiles.
The earliest dinosaur were carnivorous, they had narrow teeth with serrations designed for tearing meat. They had a reptilian like metabolism which allowed them to easily overcome the more mammal like therapsids. There are two major groups under the archosaur group’ the Ornithodira that had a small part during the middle triassic era, but in the later eras ruled as the dinosaurs, pterosaurs, and the crurotarsi which were the dominant group at this time. Including strictly triassic groups; the rauisuchians, the phytosaurs and aetosaurs along with the earliest ancestors of the crocodilians.
Most of the large crurotarsi archosaurs are known as thecodonts, fell into extincting about 195 million years ago, leaving the pterosaurs as the survivors of this earliest group along with the ornithdodiras, the first sphenosuchias, and [[protosuchia]s as their descendents among the crocodilia to flourish in the jurassic and cretaceous periods. They were so dominating in the mesozoic period that it’s lightly referred to as “The Age of the Archosaurs.”
Most of the archosaurs perished around 65 million years ago, in the middle of the cretaceous period. The only archosaurs that were able to survive through the extinction were, present day birds and modern crocodylia, including aligators.