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Cladus: Eukaryota
Supergroup: Opisthokonta
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclassis: Tetrapoda
Classis: Reptilia
Subclassis: Anapsida
Ordines: †Captorhinida - †Mesosauria - †Procolophonia - Testudines


Anapsida (Osborn, 1903)


Vernacular names
Català: Anapsid
Deutsch: AnapsideReptilien
English: Anapsid
Español: Anapsida
Français: Cheloniens
Italiano: Anapsida
日本語: 無弓亜綱
Nederlands: Anapsida
‪Norsk (bokmål)‬: Urreptiler
Occitan: Anapsida
Polski: Anapsida
Português: Anapsida
Slovenčina: Anapsida
Suomi: Anapsidi
Svenska: Anapsida
Українська: Анапсиди

An anapsid is an amniote whose skull does not have openings near the temples.[1]

While "anapsid reptiles" or "anapsida" are traditionally spoken of as if they were a monophyletic group, it has been suggested that several groups of reptiles that had anapsid skulls may be only distantly related: scientists still debate the exact relationship between the basal (original) reptiles which first appeared in the late Carboniferous, the various Permian reptiles which had anapsid skulls, and the Testudines (turtles, tortoises, and terrapins). Many modern paleontologists believe the Testudines are descended from diapsid reptiles which lost their temporal fenestrae, although that view is not generally accepted (see Parareptilia for details and references).
Anapsid skull of Caretta caretta (Loggerhead sea turtle) -- a Testudine

The only living reptiles with anapsid skulls are the Testudines. The earliest fossil testudines are from the Triassic, but they were already too like modern turtles to be near the start of their lineage - in particular they already had limb joints within the rib cage. The main article about Testudines covers the debate about their ancestry.

Most of the other reptiles with anapsid skulls, including the millerettids, nyctiphrurets, and pareiasaurs, became extinct in the late Permian period by the Permian-Triassic extinction event. But the procolophonids managed to survive into the Triassic.


1. ^ Pough, F. H. et al. (2002) Vertebrate Life, 6th Ed. Prentice Hall Inc., Upper Saddle River, NJ. ISBN 0130412481

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Source: Wikipedia, Wikispecies: All text is available under the terms of the GNU Free Documentation License