Anapsid

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Anapsids
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Subphylum:Vertebrata
Infraphylum:Tetrapoda
Microphylum:Amniota
Nanophylum:Sauropsida
Superclass:Anapsida
Osborn, 1903
Orders

Testudines (Turtles)
Millerettid - extinct
Nyctiphruret - extinct
Pareiasaur - extinct
Procolophonoid - extinct

The anapsids are a group of amniotes, characterized by skulls without openings near the temples. The only extant members are the Testudines - turtles, tortoises, and terrapins. Various other groups, however, are known from Permian and Triassic fossils. The anapsids have traditionally been treated as a subclass of the class Reptilia, but as this group is paraphyletic they are sometimes placed in a separate class Anapsida.

Most of the anapsid orders, including the millerettids, nyctiphrurets, and pareiasaurs, were extincted in the late Permian period by the Permian-Triassic extinction event. Both the procolophonoids and some ancient ancestors of the testudines managed to survive into the Triassic, and the testidunes are the only surviving order.

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