are a group of amniotes, characterized by skulls without openings near the temples
. The only extant members are the Testudines
, tortoises, and terrapins. Various other groups, however, are known from Permian
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 groups 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.
Introduction to Anapsida from UCMP