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. Living subgroups Class Synapsida    Class Mammalia(mammals) Class Sauropsida    Anapsida        Testudines(turtles)    Diapsida        Lepidosauria           Squamata(lizards& snakes)           Sphenodontida(tuatara)        Archosauria           Crocodilia(crocodiles)           Class Aves(birds) The amniotes are a microphylum of tetrapod vertebrates that include the Synapsida (mammals) and Reptilia (reptiles and dinosaurs, including birds). ... Large holes in the side of the skull. ... The Angkor Wat Hindu temple in Cambodia is the largest in the world. ... Families See text Turtles are reptiles of the order Testudinata, most of whose body is shielded by a special bony shell developed from their ribs. ... Suborders Cryptodira Pleurodira See text for families. ... Genera Chersina Dipsochelys Furculachelys Geochelone Gopherus Homopus Indotestudo Kinixys Malacochersus Manouria Psammobates Pyxis Testudo A tortoise is a land-dwelling reptile of the order Testudines. ... Wiktionary has related dictionary definitions, such as: terrapin Terrapin may mean: An amphibious reptile turtle, which spends its time both in the water and on land. ... The Permian is a geologic period that extends from about 299. ... The Triassic is a geologic period that extends from about 245 to 202 Ma (million years ago). ... Orders See text. ... Paraphyletic - Wikipedia /**/ @import /skins-1. ...

Most of the anapsid orders, including the millerettids, nyctiphrurets, and pareiasaurs, became extinct in the late Permian period by the Permian-Triassic extinction event. Both the procolophonids and some ancient ancestors of the testudines managed to survive into the Triassic, and the testidunes are the only surviving order. The milleretids is an extinct group of anapsids that lived in South Africa during the Upper Permian. ... Genera Bradysaurus Nochelesaurus Embrithosaurus Deltavjatia Velosauria Shihtienfenia Pareiasuchus Pareiasaurus Scutosaurus Elginia Nanopareia Anthodon The Pareiasaurs - family Pareiasauridae - are a group of medium-sized to very large (60 cm to 3 meters long), stocky, early, reptilian herbivores, that flourished during the Permian period. ... The Permian is a geologic period that extends from about 299. ... The Permian-Triassic extinction event, labeled End P here, is the most significant extinction event in this plot for marine fossiliferous genera. ... Families See text Turtles are reptiles of the order Testudinata, most of whose body is shielded by a special bony shell developed from their ribs. ... The Triassic is a geologic period that extends from about 245 to 202 Ma (million years ago). ...

Recently it has been suggested that the Testudines are not actually a member of the Anapsid clade, but instead diapsids, and that the similarities ensued from convergent evolution. Those favouring this hypothesis are divided on which clade within the diapsids to place the Testudines: either the lepidosaurian or archosaurian branches. Groups See Text Diapsids (two arches) are a group of tetrapod animals that developed two holes (temporal fenestra) in each side of their skulls, about 300 million years ago during the late Carboniferous period. ... -1...

See also

• Parareptilia

External links

• Introduction to Anapsida from UCMP