Archosaurs, or ruling reptiles, first appeared during the Triassic, a period in Earths history that lasted from 251 to 200 million years BC. Some archosaurs would have gradually abandoned the crawling stance, characterized by the belly hugging the ground and legs attached to the sides of the body (like modern crocodiles).
Archosaurs, or ruling reptiles, first appeared during the Triassic, a period in Earths history that lasted from 251 to 200 million years BC. Some archosaurs would have gradually abandoned the crawling stance, characterized by the belly hugging the ground and legs attached to the sides of the body (like modern crocodiles).