Anapsida

# non-chelonians

Include: Mesosauridae, Millerettidae, Acleistorhinus, Lanthanosuchidae, Macroleter, Nyctiphruretia, Pareiasauria, Procolophonoidea

Chelonia (turtles, tortoises and terrapins)

Romeriida

# 'non-diapsids'

Include: Captorhinidae and Protorothyrididae

Diapsida (lizards, snakes, crocodiles, dinosaurs, birds, and relatives)

Lepidosauromorpha

'non-Lepidosauria'

Include: Saurosternon, Paliguana

Lepidosauria

Squamata (lizards and snakes)

Infraclass: Rhynchocephalia (tuataras and extinct relatives)

Tuataras used to be widespread in New Zealand but are now limited to a few islands off the coast of New Zealand. There was thought to be only one species on these islands but genetic analysis has revealed two: Sphenodon punctatus and Sphenodon guentheri. Tuataras were abundant over 200 million years ago and these two species are all that remain. They look like lizards but the structure of their skull is different and their teeth are not separate structures but serrations along the edges of the upper and lower jaws.  

Archosauromorpha

# 'non-Archosauria'

Include: Proterochapmsia, Erythrosuchia, Proterosuchia, Prolacertiformes, Trilophosauria, Rhynchosauria, Choristodera, Placodontia

Archosauria

# various fossil groups

Crocodylomorpha (crocodiles and extinct relatives)

Dinosauria (dinosaurs, including birds)

Ornithischia (bird-hipped plant-eating dinosaurs)

Saurischia

Sauropodomorpha (long-necked plant-eating dinosaurs)

Theropoda (bipedal predatory dinosaurs, including birds)

various fossil dinosaurs

Coelurosauria (tyrannosaurs, Oviraptor, Velociraptor, birds and relatives)

various fossil dinosaurs

Include: Ornitholestes, Compsognathidae, Alvarezsauridae, Ornithomimidae, Therizinosauridae, Tyrannosauroidea

Maniraptora

various fossil dinosaurs

Include: Oviraptorosauria, Dromaeosauridae and Troodontidae

Aves (birds)