Illustration of UR 357, the holotype specimen of Poposaurus gracilis (1915) in the collections of Field Museum.
Scientific classification
Domain:
Eukaryota
Kingdom:
Animalia
Phylum:
Chordata
Class:
Reptilia
Clade:
Archosauria
Clade:
Pseudosuchia
Clade:
†Poposauroidea
Family:
†Poposauridae
Genus:
†Poposaurus Mehl, 1915
Species
†P. gracilis Mehl, 1915 (type)
†P. langstoni (Long and Murry, 1995 [originally Lythrosuchus langstoni])
Synonyms
Lythrosuchus Long and Murry, 1995
Poposaurus is an extinct genus of pseudosuchian archosaur from the Late Triassic of the southwestern United States. It belongs to the clade Poposauroidea, an unusual group of Triassic pseudosuchians that includes sail-backed, beaked, and aquatic forms. Fossils have been found in Wyoming, Utah, Arizona, and Texas. Except for the skull, most parts of the skeleton are known. The type species, P. gracilis, was described and named by Maurice Goldsmith Mehl in 1915. A second species, P. langstoni, was originally the type species of the genus Lythrosuchus. Since it was first described, Poposaurus has been variously classified as a dinosaur, a phytosaur, and a "rauisuchian".
Like theropod dinosaurs, Poposaurus was an obligate biped, meaning that it walked on two legs rather than four. However, as a pseudosuchian, it is more closely related to living crocodilians than to dinosaurs.[1]Poposaurus is thought to have evolved this form of locomotion independently, possibly from early archosaurs' ability to high walk.
^Gauthier, J.A.; Nesbitt, S.J.; Schachner, E.R.; Bever, G.S.; Joyce, W.G. (2011). "The bipedal stem crocodilian Poposaurus gracilis: inferring function in fossils and innovation in archosaur locomotion". Bulletin of the Peabody Museum of Natural History. 52 (1): 107–126. doi:10.3374/014.052.0102. S2CID 86687464.
described, Poposaurus has been variously classified as a dinosaur, a phytosaur, and a "rauisuchian". Like theropod dinosaurs, Poposaurus was an obligate...
by Sterling Nesbitt in 2011, is "the least inclusive clade containing Poposaurus and Crocodylus niloticus (the Nile crocodile). Most groups of paracrocodylomorphs...
that Poposaurus was a pseudosuchian rather than a dinosaur. Other genera such as Sillosuchus and Shuvosaurus were later erected. Like Poposaurus, Shuvosaurus...
crocodiles. An early cladistic analysis of crocodylotarsan archosaurs included Poposaurus, Postosuchus, Teratosaurus, and Bromsgroveia within Poposauridae. However...
1127/njgpa/201/1996/303. Weinbaum, J.C.; Hungerbühler, A. (2007). "A revision of Poposaurus gracilis (Archosauria: Suchia) based on two new specimens from the Late...
such as the heavily armored aetosaurs, and several were bipedal, such as Poposaurus and Postosuchus. The bizarre, ornithomimid-like shuvosaurids were both...
25(1):78–86. Weinbaum, J. C. and Hungerbüler, A. (2007). A revision of Poposaurus gracilis (Archosauria: Suchia) based on two new specimens from the Late...
inclusive clade containing Crocodylus niloticus (the Nile crocodile), but not Poposaurus gracilis, Ornithosuchus longidens, or Aetosaurus ferox, all of which were...
identified pseudosuchian features act as evidence that poposaurids, such as Poposaurus, Sillosuchus, and Chatterjeea, and ctenosauriscids form a monophyletic...
reidentified as a "rauisuchian" pseudosuchian related to Poposaurus. This grouping of Poposaurus-like taxa was later defined as the clade Poposauroidea...
both groups that was difficult to resolve, which included Arizonasaurus, Poposaurus, and Sillosuchus. However, the characters linking these two groups were...
compared to that of Poposaurus, a Triassic pseudosuchian that walked on two legs. While the strongest leg muscles of Poposaurus are thought to drive...
R.; Bever, G. S.; Joyce, W. G. (2011). "The bipedal stem-crocodilian Poposaurus gracilis: inferring function in fossils and innovation in archosaur locomotion"...
R.; Bever, G. S. & Joyce, W. G. (2011). "The bipedal stem crocodilian Poposaurus gracilis: inferring function in fossils and innovation in archosaur locomotion"...
boot. Walker also proposed that Herrerasaurus may instead be close to Poposaurus (now considered a pseudosuchian) and the unnamed theropod from the Dockum...
Parker, William G.; Nesbitt, Sterling J. (2013). "Cranial remains ofPoposaurus gracilis(Pseudosuchia: Poposauroidea) from the Upper Triassic, the distribution...
Polyonax Ponerosteus – subsequently found to be a non-dinosaurian archosaur Poposaurus – subsequently found to be a non-dinosaurian archosaur Portellsaurus Postosuchus...
as "the most inclusive clade containing Ctenosauriscus koeneni but not Poposaurus gracilis, Effigia okeeffeae, Postosuchus kirkpatricki, Crocodylus niloticus...
exclusive clade containing closely related suchians such as Shuvosaurus and Poposaurus (Poposauroidea). Within this group, Effigia forms an even more exclusive...
related shuvosaurids Shuvosaurus and Effigia, as well as the carnivorous Poposaurus. The individual of Sillosuchus to which the original specimen belonged...
Aetosaurus and Desmatosuchus than to Leptosuchus, Postosuchus, Prestosuchus, Poposaurus, Sphenosuchus, Alligator, Gracilisuchus, and Revueltosaurus. A new genus...
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