What is Sauropsid?
{{Taxobox | name = Sauropsids | fossil_range = [[Pennsylvanian]] &ndash; Recent | image = | image_width | image_caption= Eastern [[Water dragon]], ''Physignathus lesueurii'' | regnum = [[Animal]]ia | phylum = [[Chordate|Chordata]] | subphylum = [[Vertebrate|Vertebrata]] | superclassis = [[Tetrapod]]a | unranked subclassis = [[Amniota]] | unranked ordo = '''Sauropsida''' | classis_authority = [[Edwin Stephen Goodrich|Goodrich]], 1916 | subdivision_ranks = [[Clades]] }} '''Sauropsids''' are a group of land [[vertebrate]]s which includes all existing [[reptile]]s and [[bird]]s and their [[fossil]] [[ancestor]]s. They are one of the two groups which evolved from egg-laying [[amniote]]s in the first part of the [[Carboniferous]] period.<ref name=Early>Gauthier J.A; Kluge A.G & Rowe T. 1988. The early evolution of the Amniota. pp103–155 in Michael J. Benton (ed) ''The phylogeny and classification of the tetrapods'', Volume 1: Amphibians, Reptiles, Birds. ''Systematics Association'', Special vol 35A. Clarendon Press, Oxford.</ref><ref>Gauthier J.A. 1994. The diversification of the amniotes. In D.R. Prothero and R.M. Schoch (eds) ''Major features of vertebrate evolution''. 129-159. Knoxville, Tennessee: The Paleontological Society.</ref><ref>Laurin M. & Gauthier J.A. 1996. [http://tolweb.org/Amniota/14990 Amniota, mammals, reptiles (turtles, lizards, ''Sphenodon'', crocodiles, birds) and their extinct relatives]. Version 01 January 1996. The Tree of Life Web Project.</ref> The [[synapsid]]s are the other group which evolved from amniotes. They gave rise, eventually, to the [[mammal]]s. Living sauropsids include [[lizard]]s, [[snake]]s, [[turtle]]s, [[crocodile]]s, and [[bird]]s. [[Extinction|Extinct]] sauropsids include non-avian [[dinosaur]]s, [[pterosaur]]s, [[plesiosaur]]s, [[ichthyosaur]]s, and many others. ==Origin of tetrapods== More or less, the evolution of tetrapods has taken this course: *[[Sarcopterygii]] **[[Coelacanthimorpha]] ([[Coelacanth]]s) **[[Dipnoi]] ([[lungfish]]) ***[[Tetrapodomorpha]] The ea