Rauisuchia are a poorly known assemblage of predatory and mostly large (often 4 to 6 meters) Triassic archosaurs. Originally it was believed that they were related to Erythrosuchids (Sill, 1974), but it is now known that they are crurotarsans (Benton 2004). Three families are generally recognised: Prestosuchidae, Rauisuchidae, and Poposauridae, as well as a number of forms (e.g. those from the Olenekian of Russia) that are too primitive and/or poorly known to fit in any of these groups. There has been considerable suggestion that the group as currently defined is paraphyletic, representing a number of related lineages independently evolving and filling the same ecological niche of medium to top terrestrial predator. For example, Parrish (1993) and Juul (1994) found poposaurid rauisuchians to be more closely related to Crocodilia than to prestosuchids. In a more recent study, Nesbitt (2003) presented a different phylogeny with a monophyletic Rauisuchia. The group may even be something of a "wastebasket taxon". Determining exact phylogenetic relationships is difficult because of the scrappy nature of a lot of the material. However, recent discoveries and studies such as those of Batrachotomus (Gower, 2002; Benton & Walker 2002) are shedding light on the evolutionary relationships of this poorly known but fascinating group. The Triassic is a geologic period that extends from about 251 ± 0. ... Image File history File links Size of this preview: 800 × 382 pixelsFull resolution (1000 × 478 pixel, file size: 40 KB, MIME type: image/jpeg) Prestosuchus, pencil drawing, based on the skeleton cast on display at the American Museum of Natural History Author:User:ArthurWeasley File history Legend: (cur) = this is... Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. ... “Animalia” redirects here. ... Typical Classes See below Chordates (phylum Chordata) are a group of animals that includes the vertebrates, together with several closely related invertebrates. ... Clades Subclass Anapsida Subclass Diapsida Infraclass Lepidosauromorpha Infraclass Archosauromorpha Sauropsids are a diverse group of mostly egg-laying vertebrate animals. ... Groups See Text Diapsids (two arches) are a group of tetrapod animals that developed two holes (temporal fenestra) in each side of their skulls, about 300 million years ago during the late Carboniferous period. ... Orders See text Archosauromorpha (Greek for ruling lizard forms) is an Infraclass of diapsid reptiles that first appeared during the late Permian and became more common during the Triassic. ... Subtaxa Phytosauridae Prestosuchidae Ornithosuchidae Stagonolepididae Rauisuchidae Poposauridae Crocodylomorpha     Sphenosuchia     Crocodilia Crurotarsi (cross-ankles) is a node-based taxon created by Paul Sereno in 1991 to supplant the old term Pseudosuchia. ... Paraphyletic - Wikipedia /**/ @import /skins-1. ... Friedrich von Huene (March 22, 1875 – April 4, 1969) was a German paleontologist who named more dinosaurs in the early 20th century than anyone else in Europe. ... 1942 (MCMXLII) was a common year starting on Thursday (the link is to a full 1942 calendar). ... Genera Batrachotomus Mandasuchus Prestosuchus Ticinosuchus Saurosuchus Yarasuchus Prestosuchidae are a group of Triassic carnivorous archosaurs. ... Genera Rauisuchus Fasolasuchus Lotosaurus Heptasuchus Tikisaurus ?Teratosaurus ?Postosuchus Rauisuchidae are a group of large (upto 6 meters or more) predatory Triassic archosaurs, and constitute advanced representatives of the larger group Rauisuchia. ... Genera Bomsgroveia Poposaurus Postosuchus Sillosuchus Shuvosaurus Teratosaurus The Poposauridae are a family of large (around 2. ... The Triassic is a geologic period that extends from about 251 ± 0. ... -1... Genera see Taxonomy Erythrosuchidae are a family of large basal archosaurian carnivores that lived from the later Early Triassic (Olenekian) to the early Middle Triassic (Anisian). ... Subtaxa Phytosauridae Prestosuchidae Ornithosuchidae Stagonolepididae Rauisuchidae Poposauridae Crocodylomorpha     Sphenosuchia     Crocodilia Crurotarsi (cross-ankles) is a node-based taxon created by Paul Sereno in 1991 to supplant the old term Pseudosuchia. ... Genera Batrachotomus Mandasuchus Prestosuchus Ticinosuchus Saurosuchus Yarasuchus Prestosuchidae are a group of Triassic carnivorous archosaurs. ... Genera Rauisuchus Fasolasuchus Lotosaurus Heptasuchus Tikisaurus ?Teratosaurus ?Postosuchus Rauisuchidae are a group of large (upto 6 meters or more) predatory Triassic archosaurs, and constitute advanced representatives of the larger group Rauisuchia. ... Genera Bomsgroveia Poposaurus Postosuchus Sillosuchus Shuvosaurus Teratosaurus The Poposauridae are a family of large (around 2. ... The Olenekian (also known as the Yongningzhenian) is a stage of the Early Triassic epoch. ... Paraphyletic - Wikipedia /**/ @import /skins-1. ... black: range of Crocodilia Families Gavialidae Alligatoridae Crocodylidae Crocodilia is an order of large reptiles that appeared about 84 million years ago in the Late Cretaceous Period (Campanian stage). ... In phylogenetics, a group is monophyletic (Greek: of one stem) if all organisms in that group are known to have developed from a common ancestral form, and all descendants of that form are included in the group. ... Wastebin taxon (also called a wastebasket, or dustbin taxon) is a term used in taxonomic circles that refers to a taxon that has the sole purpose of classifying organisms that dont fit anywhere else. ... Batrachotomus (meaning frog slicer) belongs to Rauisuchia, a group of predatory and large Triassic archosaurs. ...

José Bonaparte and following him Michael Benton argue (Bonaparte 1981, Benton, 1984) that rauisuchians such as Saurosuchus developed an erect stance independently of and differently to dinosaurs, by means of having the femur vertical and angling the acetabulum ventrally, rather than having an angled neck or curve in the femur. They refer to this as the pillar-erect posture. José Fernando Bonaparte, Ph. ... Michael Benton is a professor of vertebrate palaeontology in the Department of Earth Sciences at the University of Bristol. ... Species  ? Saurosuchus (lizard crocodile) is an extinct genus of archosaur reptile belonging to the rauisuchian order. ... Orders & Suborders Saurischia Sauropodomorpha Theropoda Ornithischia Thyreophora Ornithopoda Marginocephalia Dinosaurs were vertebrate animals that dominated the terrestrial ecosystem for over 160 million years, first appearing approximately 230 million years ago. ... The femur or thigh bone is the longest, most voluminous, and strongest bone of the mammalian bodies. ... Categories: Anatomy stubs | Skeletal system ...

The erect gait indicates that these animals were clearly active, agile predators, with locomotor superiority over the kannemeyerid dicynodonts and abundant rhynchosaurs on which they fed. They were successful animals, the largest with skulls a meter or more in length, and continued right until the end of the Triassic, when, along with many other large archosaurs, they were killed off by the end Triassic extinction event. With their demise, theropod dinosaurs were able to emerge as the sole large terrestrial predators; meat-eating dinosaur footprints suddenly increase in size at the start of the Jurassic, when rauisuchians are absent (Olsen et al. 2002).(Although, however, recently found Cretaceous fossils that were originally thought to be those of crocodiles, but resemble rauisuchians, might suggest that a few rauisuchians survived under the shadows of dinosaurs until the K-T Event.) Kannemeyeridae: A family of large, stocky, beaked and sometimes tusked dicynodonts, they were the dominant large terrestrial herbivores through most of the Triassic period. ... Genera Mesosuchus Howesia Stenaulorhynchys Rhynchosaurus Otischalia Isalorhynchus Hyperodepedon Rhynchosaurs were a group of unusual Triassic diapsid reptiles related to the archosaurs. ... Comparison of the intensity of the T-J extinction event, labeled here End Tr to other extinction events in the last 500 million years. ... Families See text Theropods (beast foot) are a group of bipedal, primarily carnivorous dinosaurs, belonging to the saurischian (lizard-hip) family. ... The Jurassic Period is a major unit of the geologic timescale that extends from about 199. ... The Cretaceous-Tertiary (KT) extinction event, also known as the KT boundary (from German: Kreide-Tertiär-Grenzschicht), was a period of massive extinction of species, about 65. ...

Well-known Rauisuchians include Ticinosuchus of the Middle Triassic of Europe (Switzerland and Northern Italy), Saurosuchus of the late Triassic (Late Carnian) of South America (Argentina), and Postosuchus of the late Triassic (Late Carnian to Early Norian) of North America (SW USA). One Rauisuchian, Teratosaurus, was for a long time even considered an early theropod dinosaur! Ticinosuchus is an extinct genus of archosaur reptile that was about 3 m (10 ft) long. ... Species  ? Saurosuchus (lizard crocodile) is an extinct genus of archosaur reptile belonging to the rauisuchian order. ... The Carnian is a stage on the geologic time scale occuring from 228 +/- 2 to 216. ... Binomial name Chatterjee, 1985 Postosuchus was a basal archosaur which lived in what is now North America during the middle through to the late Triassic period (228-202 million years ago). ... The Carnian is a stage on the geologic time scale occuring from 228 +/- 2 to 216. ... The Norian Stage was a portion of the Triassic geological period. ... Teratosaurus was a genus of rauisuchian from the Triassic Period. ... Families See text Theropods (beast foot) are a group of bipedal, primarily carnivorous dinosaurs, belonging to the saurischian (lizard-hip) family. ...

External links

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• Palaeos

References

• Benton, M. J. (1984). "Rauisuchians and the success of dinosaurs". Nature 310: 101. DOI:10.1038/310101a0. 

• Benton, M. J. (2004). Vertebrate Paleontology, 3rd ed., Oxford: Blackwell Science Ltd. ISBN 0632056371. 

• Benton, M. J.; Walker, A. D. (2002). "Erpetosuchus, a crocodile-like basal archosaur from the Late Triassic of Elgin, Scotland". Zool. J. Linn. Soc 136 (1): 25-47. DOI:10.1046/j.1096-3642.2002.00024.x. ISSN 0024-4082. 

• Bonaparte, J. F. (1984). "Locomotion in rauisuchid thecodonts". Journal of Vertebrate Paleontology 3 (4): 210-218. 

• Carroll, R. L. (1988). Vertebrate Paleontology and Evolution. New York: WH Freeman & Co. ISBN 0716718227. 

• Gower, D. J. (2002). "Braincase evolution in suchian archosaurs (Reptilia: Diapsida): evidence from the rauisuchian Batrachotomus kupferzellensis". Zool. J. Linn. Soc 136 (1): 49-76. DOI:10.1046/j.1096-3642.2002.00025.x. 

• Juul, L. (1994). "The phylogeny of basal archosaurs". Palaeontologia Africana 31: 1-38. 

• Nesbitt, S. J. (2003). "Arizonasaurus and its implications for archosaur divergence". Proceedings of the Royal Society B 270 (Suppl. 2): S234-S237. DOI:10.1098/rsbl.2003.0066. ISSN 0962-8452. 

• Olsen, P. E.; Kent, D. V.; Sues, H.-D.; Koeberl, C.; Huber, H.; Montanari, E. C.; Rainforth, A.; Fowell, S. J.; Szajna, M. J.; and Hartline, B. W. (2002). "Ascent of Dinosaurs Linked to an Iridium Anomaly at the Triassic-Jurassic Boundary". Science 296: 1305-1307. 

• Parrish, J. M. (1993). "Phylogeny of the Crocodylotarsi, with reference to archosaurian and crurotarsan monophyly". Journal of Vertebrate Paleontology 13: 287-308. 

• Sill, W. D. (1974). "The anatomy of Saurosuchus galilei and the relationships of the rauisuchid thecodonts". Bulletin of the Museum of Comparative Zoology 146: 317-362. ISSN 0027-4100.