Articles relating to diapsids, a group of amniote tetrapods that developed two holes (temporal fenestra) in each side of their skulls about 300 million years ago during the late Carboniferous period.[1] The diapsids are extremely diverse, and include all crocodilians, lizards, snakes, tuatara, turtles, and birds.[2] At least 7,925 species of diapsid reptiles[3] exist in environments around the world today, nearly 18,000 when birds are included.