Herrerasaur 3539319 224478550 2008-07-09T00:52:23Z Insanity Incarnate 3763104 Reverted edits by [[Special:Contributions/68.192.69.162|68.192.69.162]] (using [[WP:HG|Huggle]]) {{Taxobox | name = Herrerasaurs | fossil_range = [[Late Triassic]] | image = | image_width = 200px | image_caption = ''[[Herrerasaurus]]'' | regnum = [[Animal]]ia | phylum = [[Chordate|Chordata]] | classis = [[Reptile|Sauropsida]] | superordo = [[Dinosaur]]ia | ordo = [[Saurischia]] | subordo = ?[[Theropod]]a | infraordo = '''Herrerasauria''' | infraordo_authority = Galton, 1985 | subdivision_ranks = Genera | subdivision = * ''[[Staurikosaurus]]'' * ''[[Herrerasaurus]]'' * ''[[Chindesaurus]]'' * ?''[[Caseosaurus]]'' }} '''Herrerasaurs''' are among the oldest known [[dinosaur]]s, appearing in the [[fossil]] record about 228 million years ago (mid-[[Triassic]]). They became extinct by the end of the Triassic period. Herrerasaurs were small to medium-sized [[carnivore]]s generally resembling [[theropod]]s, which may be their closest relatives. The best known representatives of this group are from [[South America]] ([[Brazil]], [[Argentina]]), where they were first discovered in the 1960s. A nearly complete skeleton of ''Herrerasaurus ischigulastensis'' was discovered in the [[Ischigualasto]] Formation in [[San Juan Province|San Juan]], Argentina, in [[1988]]. Less complete herrerasaurians have been found in North America, and they may have inhabited other continents as well. Herrerasaurian anatomy is unusual and specialized, and they are not considered to be ancestral to any later dinosaur group. They often present a mixture of very primitive and derived traits. The [[acetabulum]] is only partly open, and there are only two [[sacral vertebrae]], the lowest number among dinosaurs. The [[pubic bone]] has a derived structure, being rotated somewhat posteriorly and folded to create a superficially [[tetanuran]]-like terminal expansion, especially prominent in ''H. ischigulastensis''. The hand is primitive in having five [[metacarpal]]s and the third finger longer than the second, but theropod-like in having only three long fingers, with curved claws. Herrerasaurids also have a hinged [[mandible]] like theropods, but this may have evolved independently. ==Taxonomy== *'''Order [[Saurischia]]''' **?'''Suborder [[Theropoda]]''' ***'''Infraorder Herrerasauria''' ****Family Staurikosauridae *****''[[Staurikosaurus]]'' ****Family Herrerasauridae *****?''[[Caseosaurus]]'' *****''[[Chindesaurus]]'' *****''[[Herrerasaurus]]'' [[Category:Saurischians]] {{portalpar|Dinosaurs}} [[ca:Herrerasaure (infraordre)]] [[de:Herrerasauridae]] [[es:Herrerasauria]] [[fr:Herrerasauridae]] [[it:Herrerasauridae]] [[hu:Herrerasauria]] [[pl:Herrerazaury]] [[zh:艾雷拉龍下目]]