Diapsida

Diapsids ("two arches") are a group of tetrapods that developed two holes (temporal fenestra) in each side of their skulls, about 300 million years ago during the late Carboniferous period. Living diapsids are extremely diverse, and include all crocodiles, lizards, snakes, tuataras, and birds. Although some diapsids have lost either one hole (lizards), or both holes (snakes), or have a heavily restructured skull (modern birds), they are still classified as diapsids based on their ancestry. For more information, visit the Wikipedia entry Get back to Animalia
†Aetosaurs	Archosauromorpha	†Arizonasaurus	Birds
†Champsosaurus	Crocodylomorpha	Dinosaurs	†Euparkeria
Hyperodapedon	†Ichthyosaurs	Lepidosauromorpha	Lizards
†Mosasaurs	Neodiapsida	†Ornithosuchus	†Phytosaurs
†Plesiosaurs	Prestosuchus	†Postosuchus	† Proterosuchids
†Protochirotherium	†Protorosaurs	†Pterosaurs	† Sauropterygia
Snakes	Tuataras