Poposauridae is a

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

of large

carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose nutrition and energy requirements are met by consumption of animal tissues (mainly mu ...

archosaur Archosauria () or archosaurs () is a clade of diapsid sauropsid tetrapods, with birds and crocodilians being the only extant taxon, extant representatives. Although broadly classified as reptiles, which traditionally exclude birds, the cladistics ...

s which lived alongside

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

s during the

Late Triassic The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch a ...

. They were around long. Poposaurids are known from fossil remains from North and South America. While originally believed to be

theropod Theropoda (; from ancient Greek , (''therion'') "wild beast"; , (''pous, podos'') "foot"">wiktionary:ποδός"> (''pous, podos'') "foot" is one of the three major groups (clades) of dinosaurs, alongside Ornithischia and Sauropodom ...

s (they mirrored the theropods in a number of respects, such as features of the skull and bipedal locomotion),

cladistic Cladistics ( ; from Ancient Greek 'branch') is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is ...

analysis has shown them to be more closely related to

crocodiles Crocodiles (family Crocodylidae) or true crocodiles are large, semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term "crocodile" is sometimes used more loosely to include all extant member ...

. An early cladistic analysis of crocodylotarsan

s included ''

Poposaurus ''Poposaurus'' is an extinct genus of pseudosuchian archosaur from the Late Triassic of the southwestern and eastern United States. It belongs to the clade Poposauroidea, an unusual group of Triassic pseudosuchians that includes sail-backed, bea ...

'', ''

Postosuchus ''Postosuchus'', meaning "Crocodile from Post", is an extinct genus of rauisuchid reptiles comprising two species, ''P. kirkpatricki'' and ''P. alisonae'', that lived in what is now North America during the Late Triassic. ''Postosuchus'' is a ...

'', ''

Teratosaurus ''Teratosaurus'' is a genus of rauisuchians known from the Triassic Stubensandstein ( Löwenstein Formation - Norian stage) of Germany. It is estimated to be 6.2 meters (20.35 ft) long. Discovery In 1860, Sixt Friedrich Jakob von Kapff ...

'', and ''

Bromsgroveia ''Bromsgroveia'' is an extinct genus of predatory ctenosauriscid archosaur from the Middle Triassic Bromsgrove Sandstone of England. Ctenosauriscids were a group of rauisuchians that was related to the ancestors of modern crocodiles and alligato ...

'' within Poposauridae.Parrish JM. 1993. Phylogeny of the Crocodylotarsi, with reference to archosaurian and crurotarsan monophyly. ''Journal of Vertebrate Paleontology'' 13: 287-308. However, later studies found ''

'' to be a

rauisuchid Rauisuchidae is a group of large (up to ) predatory Triassic archosaurs. Some disagreement exists over which genera should be included in the Rauisuchidae and which should be in the related Prestosuchidae and Poposauridae, and indeed whether thes ...

.Long RA, Murry PA. 1995. Late Triassic (Carnian and Norian) tetrapods from the Southwestern United States. ''New Mexico Museum of Natural History & Science Bulletin'' 4: 1-254.Galton PM, Walker AD. 1996. ''Bromsgroveia'' from the Middle Triassic of England, the earliest record of a poposaurid thecodontian reptile (Archosauria: Rauisuchia). ''Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen'' 201 (3): 303-325. All recent phylogenetic analyses place ''

'' either as a rauisuchid Weinbaum JC, Hungerbühler A. 2007. A revision of ''Poposaurus gracilis'' (Archosauria: Suchia) based on two new specimens from the Late Triassic of the southwestern U.S.A. ''Paläontologische Zeitschrift'' 81(2):131-145. or a

prestosuchid Prestosuchidae (in its widest usage) is a polyphyletic grouping of carnivorous archosaurs that lived during the Triassic. They were large active terrestrial apex predators, ranging from around in length. They succeeded the Erythrosuchidae as the ...

.Gower DJ. 2002. Brain case evolution in suchian archosaurs: evidence from the rauisuchian ''Batrachotomus''. ''Zoological Journal of the Linnean Society'' 136: 49-76.Nesbitt SJ, Norell MA. 2006. Extreme convergence in the body plans of an early suchian (Archosauria) and ornithomimid dinosaurs (Theropoda). ''Proceedings of the Royal Society of London B'' 273: 1045–1048.Nesbitt S. 2007. The anatomy of ''Effigia okeeffeae'' (Archosauria, Suchia), theropod-like convergence, and the distribution of related taxa. ''Bulletin of the American Museum of Natural History'' 302: 84 pp.

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- Dinosaur Mailing List archives {{Taxonbar, from=Q528929 * Late Triassic first appearances Late Triassic extinctions Pseudosuchian families

Genera

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