Temporal range: Guadalupian - Late Triassic, 265–200Ma possible descendant taxon Testudines survives to present
The Procolophonia are a suborder of herbivorous reptiles that lived from the Middle Permian till the end of the Triassic period, and are thought to be extinct today. They were originally included as a suborder of the Cotylosauria (later renamed Captorhinida Carroll 1988) but are now considered a clade of Parareptilia. They are closely related to other generally lizard-like Permian reptiles such as the Millerettidae, Bolosauridae, Acleistorhinidae, Lanthanosuchidae, and Nyctiphruretidae, all of which are included under the Anapsida or "Parareptiles" (as opposed to the Eureptilia).
There are two main groups of Procolophonia, the small, lizard-like Procolophonoidea, and the Pareiasauroidea, which include the large, armoured Pareiasauridae. Smaller groups like Rhipaeosauridae and Sclerosauridae might be placed in either superfamily, or prior to both, although according to the traditional classification of Carroll 1988 the Rhipaeosauridae are classified with the Pareiasaurs and the Sclerosaurs with the Procolophonids.
Relation to Turtles
The Procolophonia are traditionally thought to be ancestral to the turtles, although experts disagree over whether turtle ancestors are to be sought among the Procolophonidae, the Pareiasauridae (Lee 1995,1996, 1997), or simply a generic Procolophonian ancestor. Laurin & Reisz, 1995 and Laurin & Gauthier 1996 define the Procolophonia cladistically as "The most recent common ancestor of pareiasaurs, procolophonids, and testudines (Chelonia), and all its descendants", and list a number of autapomorphies. However, Rieppel and deBraga 1996 and deBraga & Rieppel, 1997 argue that turtles evolved from Sauropterygians, which would mean that the Parareptilia and Procolophonia constitute wholly extinct clades that are only distantly related to living reptiles. However this is still a topic of debate.
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