This MedLibrary.org supplementary page on Procolophonia is provided directly from the open source Wikipedia as a service to our readers. Please see the note below on authorship of this content, as well as the Wikipedia usage guidelines. To search for other content from our encyclopedia supplement, please use the form below:
Related Sponsors
| Procolophonia Fossil range: Permian to Triassic (if incl. Turtles then Permian to Recent) |
||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
 |
||||||||||||||||
| Scientific classification | ||||||||||||||||
|
||||||||||||||||
| Families | ||||||||||||||||
|
Procolophonoidea Pareiasauroidea |
The Procolophonia are an suborder of herbivorous reptiles that lived from the Middle Permian till the end of the Triassic period. 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).
Contents |
Subclassification
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 classifification 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 Procolophnidae, the Pareiasauridae (Lee 1995,1996, 1997), or simply a generic Procolophnian 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.
References
- Carroll, R. L., (1988), Vertebrate Paleontology and Evolution (incl. Appendix; Vertebrate Classification), W.H. Freeman & Co. New York
- deBraga M. & O. Rieppel. 1997. Reptile phylogeny and the interrelationships of turtles. Zoological Journal of the Linnean Society 120: 281-354.
- Kuhn, O, 1969, Cotylosauria, part 6 of Handbuch der Palaoherpetologie (Encyclopedia of Palaeoherpetology), Gustav Fischer Verlag, Stuttgart & Portland
- Laurin, M., & Gauthier, J. A., 1996 Phylogeny and Classification of Amniotes, at the Tree of Life Web Project
- Laurin, M. & R. R. Reisz. 1995. A reevaluation of early amniote phylogeny. Zoological Journal of the Linnean Society 113: 165-223.
- Lee, M. S. Y. 1995. Historical burden in systematics and the interrelationships of 'Parareptiles'. Biological Reviews of the Cambridge Philosophical Society 70: 459-547.
- Lee M. S. Y. 1996. Correlated progression and the origin of turtles. Nature 379: 812-815.
- Lee, M. S. Y., 1997: Pareiasaur phylogeny and the origin of turtles. Zoological Journal of the Linnean Society: Vol. 120, pp. 197-280
- Rieppel O. & M. deBraga. 1996. Turtles as diapsid reptiles. Nature 384: 453-455.
External links
Wikipedia content modification information:
- This page was last modified on 4 September 2008, at 23:50.
Wikipedia Authorship and Review
Wikipedia content provided here is not reviewed directly by MedLibrary.org. Wikipedia content is authored by an open community of volunteers and is not produced by or in any way affiliated with MedLibrary.org.
Wikipedia Usage Guidelines
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Procolophonia".
The URL for this specific entry is:
All Wikipedia text is available under the terms of the GNU Free Documentation License. (See Copyrights for details). Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc.