Phytosaurs are an extinct group of large, mostly semiaquatic Late Triassic archosauriform reptiles. Phytosaurs belong to the order Phytosauria and are sometimes referred to as parasuchians. Phytosauria, Parasuchia, Parasuchidae, and Phytosauridae have often been considered equivalent groupings containing the same species. Some recent studies have offered a more nuanced approach, defining Parasuchidae and Phytosauridae as nested clades within Phytosauria as a whole. The clade Phytosauria was defined by Paul Sereno in 2005 as Rutiodon carolinensis and all taxa more closely related to it than to Aetosaurus ferratus, Rauisuchus tiradentes, Prestosuchus chiniquensis, Ornithosuchus woodwardi, or Crocodylus niloticus. Phytosaurs were long-snouted and heavily armoured, bearing a remarkable resemblance to modern crocodilians in size, appearance, and lifestyle, as an example of convergence or parallel evolution.
Revueltosaurus is an extinct genus of suchian pseudosuchian from Late Triassic deposits of New Mexico, Arizona and North Carolina, United States. Many specimens, mostly teeth, have been assigned to Revueltosaurus over the years. Currently, three species are included in this genus, all of which were originally thought to represent monospecific genera of basal ornithischian dinosaurs. Revueltosaurus was about 1 meter long.
Chindesaurus is an extinct genus of basal saurischian dinosaur from the Late Triassic of the southwestern United States. It is known from a single species, C. bryansmalli, based on a partial skeleton recovered from Petrified Forest National Park in Arizona. The original specimen was nicknamed "Gertie", and generated much publicity for the park upon its discovery in 1984 and airlift out of the park in 1985. Other fragmentary referred specimens have been found in Late Triassic sediments throughout Arizona, New Mexico, and Texas, but these may not belong to the genus. Chindesaurus was a bipedal carnivore, approximately as large as a wolf.
Paleorhinus is an extinct genus of widespread basal phytosaur known from the Late Triassic. The genus was named in 1904 based on the type species Paleorhinus bransoni, which is known from Wyoming and Texas in the United States. Another valid species, Paleorhinus angustifrons from Bavaria, Germany, is also commonly referred to the genus. Paleorhinus had a length of about 2.5 meters.
Rutiodon is an extinct genus of mystriosuchine phytosaurs from the Late Triassic of the eastern United States. The type species of Rutiodon, Rutiodon carolinensis, encompasses a large number of skulls and assorted postcranial fossils discovered in the Cumnock Formation of North Carolina. Fossils referable to the species are also known from Pennsylvania, New Jersey, and Virginia. Rutiodon carolinensis is the most well-described species of phytosaur in eastern North America, though its validity as a natural taxon has been questioned. Some paleontologists also recognize a larger and more robust species, Rutiodon manhattanensis, which is known from teeth and postcranial fossils from New Jersey and Pennsylvania.
Nicrosaurus (/nɪkroʊˈsɔrəs/) is an extinct genus of phytosaur reptile existing during the Late Triassic period. Although it looked like a crocodile, it was not closely related to these creatures, instead being an example of parallel evolution. The main difference between Nicrosaurus and modern crocodiles is the position of the nostrils – Nicrosaurus's nostrils, or external nares, were placed directly in front of the forehead, whereas in crocodiles, the nostrils are positioned on the end of the snout. A 2013 study has also found that ilium of Nicrosaurus is quite distinctive from all other phytosaurs.
Acaenasuchus is an extinct genus of pseudosuchian, endemic to what would be presently be known as Arizona during the Late Triassic, specifically during the Carnian and Norian stages of the Triassic. Acaenasuchus had a stratigraphic range of approximately 11.5 million years. Acaenasuchus is further categorized as one of the type fauna that belong to the Adamanian LVF, based on the fauna of the Blue Mesa Member of the Chinle Petrified Forest Formation of Arizona, where Acaenasuchus was initially discovered.
Redondasaurus is an extinct genus or subgenus of phytosaur from the Late Triassic of the southwestern United States. It was named by Hunt & Lucas in 1993, and contains two species, R. gregorii and R. bermani. It is the youngest and most evolutionarily-advanced of the phytosaurs.
Angistorhinus is an extinct genus of phytosaur known from the Late Triassic period of Texas and Wyoming, United States. It was first named by Mehl in 1913 and the type species is Angistorhinus grandis. Other species from Texas and Wyoming, A. alticephalus, A. gracilis and A. maximus, are cospecific with the type species. Angistorhinus is known from the holotype UC 631, partial skull and lower jaws recovered from the Popo Agie Formation, Chugwater Group, Wyoming and from the associated paratype UM 531, a partial skull, TMM 31098-1, skull and lower jaws and ROM 7977, partial skull and lower jaws, recovered from the 'Pre-Tecovas Horizon' in the Dockum Group, Texas. A possible second species, A. talainti is known from the Triassic of Morocco. In 1995, Long and Murry created the new combination, Angistorhinus megalodon by synonymy for Brachysuchus. Hungerbühler and Sues (2001) hypothesised that Angistorhinus is a junior synonym of Rutiodon. However, in 2010 Michelle R. Stocker retained the validity of Brachysuchus and of A. grandis.
Mystriosuchus is an extinct genus of phytosaur that lived in the Late Triassic in Europe and Greenland. It was first named by Eberhard Fraas in 1896, and includes four species: M. planirostris, M. westphali, M. steinbergeri, and M. alleroq.
Smilosuchus is an extinct genus of leptosuchomorph parasuchid from the Late Triassic of North America.
The Cooper Canyon Formation is a geological formation of Norian age in Texas. It is one of several formations encompassed by the Dockum Group.
Machaeroprosopus is an extinct genus of mystriosuchin leptosuchomorph phytosaur from the Late Triassic of the southwestern United States. M. validus, once thought to be the type species of Machaeroprosopus, was named in 1916 on the basis of three complete skulls from Chinle Formation, Arizona. The skulls have been lost since the 1950s, and a line drawing in the original 1916 description is the only visual record of the specimen. Another species, M. andersoni, was named in 1922 from New Mexico, and the species M. adamanensis, M. gregorii, M. lithodendrorum, M. tenuis, and M. zunii were named in 1930. Most species have been reassigned to the genera Smilosuchus, Rutiodon, or Phytosaurus. Until recently, M. validus was considered to be the only species that has not been reassigned. Thus, Machaeroprosopus was considered to be a nomen dubium or "doubtful name" because of the lack of diagnostic specimens that can support its distinction from other phytosaur genera. However, a taxonomic revision of Machaeroprosopus, conducted by Parker et al. in 2013, revealed that UW 3807, the holotype of M. validus, is not the holotype of Machaeroprosopus, while the species Machaeroprosopus buceros, Machaeroprosopus being a replacement name, with a fixed type species, for Metarhinus, is the combinatio nova of the type species of the genu: Belodon buceros. Therefore, the name Pseudopalatus must be considered a junior synonym of Machaeroprosopus, and all species of the former must be reassigned to the latter. This revised taxonomy was already accepted in several studies, including Stocker and Butler (2013). Stocker and Butler (2013) also treated M. andersoni as a valid species, and not a junior synonym of Machaeroprosopus buceros as was previously suggested by Long and Murry (1995).
Parrishia is an extinct genus of sphenosuchian crocodylomorph known from the Late Triassic Chinle, Dockum, and Santa Rosa Formations in Arizona and New Mexico.
Pravusuchus is an extinct genus of leptosuchomorph parasuchid phytosaur known from the Late Triassic of Arizona, United States. It contains a single species, Pravusuchus hortus, which is known from three specimens. These specimens were previously referred to Smilosuchus or to Leptosuchus, but Pravusuchus's autapomorphy, its phylogenetic position as well as a trait shared with mystriosuchins, justified the erection of a new taxon for the material.
Brachysuchus is an extinct genus of phytosaur known from the late Triassic period of Dockum Group in Texas, United States. It is known from the holotype UMMP 10336 is composed of a skull, lower jaws and partial postcranium and from the associated paratype UMMP 14366, nearly complete skull, recovered from the 'Pre-Tecovas Horizon' in the Dockum Group. It was first named by Case in 1929 and the type species is Brachysuchus megalodon. Its closest relative was Angistorhinus. However, its rostral crest was much smaller than that of Angistorhinus, and the rostrum as a whole is shorter and thicker.
Wannia is an extinct genus of basal phytosaur reptile known from the Late Triassic of Texas, southern United States. It contains a single species, Wannia scurriensis, which is known from a single specimen. This species was originally named as a species referred to Paleorhinus and later was considered as a possible junior synonym of Paleorhinus bransoni. However its re-description revealed five autapomorphies, and a phylogenetic position as the most basal known phytosaur, justifying the erection of a new generic name for the species.
Vivaron is a genus of rauisuchid known from the Late Triassic Chinle Formation in New Mexico. It is the second rauisuchid known from the southwestern United States, and it highlights the wide biogeographic range similar rauisuchid taxa occupied during the Late Triassic across Pangaea, despite the varied faunal assemblages at different latitudes.
Land vertebrate faunachrons (LVFs) are biochronological units used to correlate and date terrestrial sediments and fossils based on their tetrapod faunas. First formulated on a global scale by Spencer G. Lucas in 1998, LVFs are primarily used within the Triassic Period, though Lucas later designated LVFs for other periods as well. Eight worldwide LVFs are defined for the Triassic. The first two earliest Triassic LVFs, the Lootsbergian and Nonesian, are based on South African synapsids and faunal assemblage zones estimated to correspond to the Early Triassic. These are followed by the Perovkan and Berdyankian, based on temnospondyl amphibians and Russian assemblages estimated to be from the Middle Triassic. The youngest four Triassic LVFs, the Otischalkian, Adamanian, Revueltian, and Apachean, are based on aetosaur and phytosaur reptiles common in the Late Triassic of the southwestern United States.
