Temporal range: Late Triassic
Poposauridae is a family of large carnivorous archosaurs which lived alongside dinosaurs during the Late Triassic. They were around 2.5 to 5 metres (8 ft 2 in to 16 ft 5 in) long. Poposaurids are known from fossil remains from North and South America. While originally believed to be theropod dinosaurs (they mirrored the theropods in a number of respects, such as features of the skull and bipedal locomotion), cladistic analysis has shown them to be of closer relation to crocodiles.
An early cladistic analysis of crocodylotarsan archosaurs included Poposaurus, Postosuchus, Teratosaurus, and Bromsgroveia within Poposauridae. However, later studies found Teratosaurus to be a rauisuchid. All recent phylogenetic analyses place Postosuchus either as a rauisuchid  or a prestosuchid.
|Nomen dubium.||Late Triassic||North America|
|Junior synonym.||Junior synonym of Poposaurus|
|Valid.||Late Triassic||North America.|
- Parrish JM. 1993. Phylogeny of the Crocodylotarsi, with reference to archosaurian and crurotarsan monophyly. Journal of Vertebrate Paleontology 13: 287-308.
- 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.
- 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. Palaeontologische Zeitschrift 81(2):131-145.
- 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.
- Galton, P. M., 1985, The poposaurid thecodontian Teratosaurus suevicus von Meyer, plus referred specimens mostly based on prosauropod dinosaurs. Stuttgarter Beitrage zur Naturkunde, B 116: 1-29.