Staurikosaurus is a genus of herrerasaurid dinosaur from the Late Triassic of Brazil, found in the Santa Maria Formation.
Herrerasauridae is a family of carnivorous dinosaurs, possibly basal to either theropods or even all of saurischians, or even their own branching from Dracohors, separate from Dinosauria altogether. They are among the oldest known dinosaurs, first appearing in the fossil record around 233.23 million years ago, before becoming extinct by the end of the Carnian stage. Herrerasaurids were relatively small-sized dinosaurs, normally no more than 4 metres (13 ft) long, although the holotype specimen of "Frenguellisaurus ischigualastensis" is thought to have reached around 6 meters long. The best known representatives of this group are from South America, where they were first discovered in the 1930s in relation to Staurikosaurus and 1960s in relation to Herrerasaurus. A nearly complete skeleton of Herrerasaurus ischigualastensis was discovered in the Ischigualasto Formation in San Juan, Argentina, in 1988. Less complete possible herrerasaurids have been found in North America and Africa, and they may have inhabited other continents as well.
"Rauisuchia" is a paraphyletic group of mostly large and carnivorous Triassic archosaurs. Rauisuchians are a category of archosaurs within a larger group called Pseudosuchia, which encompasses all archosaurs more closely related to crocodilians than to birds and other dinosaurs. First named in the 1940s, Rauisuchia was a name exclusive to Triassic archosaurs which were generally large, carnivorous, and quadrupedal with a pillar-erect hip posture, though exceptions exist for all of these traits. Rauisuchians, as a traditional taxonomic group, were considered distinct from other Triassic archosaur groups such as early dinosaurs, phytosaurs, aetosaurs, and crocodylomorphs.
Herrerasaurus is likely a genus of saurischian dinosaur from the Late Triassic period. This genus was one of the earliest dinosaurs from the fossil record. Its name means "Herrera's lizard", after the rancher who discovered the first specimen in 1958 in South America. All known fossils of this carnivore have been discovered in the Ischigualasto Formation of Carnian age in northwestern Argentina. The type species, Herrerasaurus ischigualastensis, was described by Osvaldo Reig in 1963 and is the only species assigned to the genus. Ischisaurus and Frenguellisaurus are synonyms.
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.
Spinosuchus is an extinct genus of trilophosaurid allokotosaur from the Late Triassic of Texas, southern United States. It has been assigned to a variety of groups over its history, from coelophysid dinosaur to pseudosuchian to uncertain theropod dinosaur and to Proterosuchidae. This uncertainty is not unusual, given that it was only known from a poorly preserved, wall-mounted, partial vertebral column of an animal that lived in a time of diverse, poorly known reptile groups. However, newly collected material and recent phylogenetic studies of early archosauromorphs suggest that it represents an advanced trilophosaurid very closely related to Trilophosaurus.
Lewisuchus is a genus of archosaur that lived during the Late Triassic. As a silesaurid dinosauriform, it was a member of the group of reptiles most commonly considered to be the closest relatives of dinosaurs. Lewisuchus was about 1 metre (3.3 ft) long. Fossils have been found in the Chañares Formation of Argentina. It exhibited osteoderms along its back.
Prestosuchidae is a polyphyletic grouping of carnivorous archosaurs that lived during the Triassic. They were large active terrestrial apex predators, ranging from around 2.5 to 7 metres in length. They succeeded the Erythrosuchidae as the largest archosaurs of their time. While resembling erythrosuchids in size and some features of the skull and skeleton, they were more advanced in their erect posture and crocodile-like ankle, indicating more efficient gait. "Prestosuchids" flourished throughout the whole of the middle, and the early part of the late Triassic, and fossils are so far known from Europe, India, Africa (Tanzania), Argentina, and Paleorrota in Brazil. However, for a long time experts disagree regarding the phylogenetic relationships of the group, what genera should be included, and whether indeed the "Prestosuchidae" constitute a distinct family.
Teleocrater is a genus of avemetatarsalian archosaur from the Middle Triassic Manda Formation of Tanzania. The name was coined by English paleontologist Alan Charig in his 1956 doctoral dissertation, but was only formally published in 2017 by Sterling Nesbitt and colleagues. The genus contains the type and only species T. rhadinus. Uncertainty over the affinities of Teleocrater have persisted since Charig's initial publication; they were not resolved until Nesbitt et al. performed a phylogenetic analysis. They found that Teleocrater is most closely related to the similarly enigmatic Yarasuchus, Dongusuchus, and Spondylosoma in a group that was named the Aphanosauria. Aphanosauria was found to be the sister group of the Ornithodira, the group containing dinosaurs and pterosaurs.
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".
Dinosauromorpha is a clade of avemetatarsalians that includes the Dinosauria (dinosaurs) and some of their close relatives. It was originally defined to include dinosauriforms and lagerpetids, with later formulations specifically excluding pterosaurs from the group. Birds are the only dinosauromorphs which survive to the present day.
Saurosuchus is an extinct genus of large loricatan pseudosuchian archosaurs that lived in South America during the Late Triassic period. It was a heavy, ground-dwelling, quadrupedal carnivore, likely being the apex predator in the Ischigualasto Formation.
Ornithosuchidae is an extinct family of pseudosuchian archosaurs from the Triassic period. Ornithosuchids were quadrupedal and facultatively bipedal, meaning that they had the ability to walk on two legs for short periods of time. They had distinctive, downturned snouts, unique, "crocodile-reversed" ankle bones, and several other features that distinguish them from other archosaurs. Ornithosuchids were geographically widespread during the Carnian and Norian stages of the Late Triassic with members known from Argentina, Brazil, and the United Kingdom. Four genera, comprising Ornithosuchus, Venaticosuchus, Dynamosuchus, and Riojasuchus are presently known. The family was first erected by German paleontologist Friedrich von Huene in 1908.
The Santa Maria Formation is a sedimentary rock formation found in Rio Grande do Sul, Brazil. It is primarily Carnian in age, and is notable for its fossils of cynodonts, "rauisuchian" pseudosuchians, and early dinosaurs and other dinosauromorphs, including the herrerasaurid Staurikosaurus, the basal sauropodomorphs Buriolestes and Saturnalia, and the lagerpetid Ixalerpeton. The formation is named after the city of Santa Maria in the central region of Rio Grande do Sul, where outcrops were first studied.
Yarasuchus is an extinct genus of avemetatarsalian archosaur that lived during the Anisian stage of the Middle Triassic of India. The genus was named and described in 2005 from a collection of disarticulated but fairly complete fossil material found from the Middle Triassic Yerrapalli Formation. The material is thought to be from two individuals, possibly three, with one being much more complete and articulated than the other. The type and only species is Y. deccanensis. Yarasuchus was a quadruped roughly 2–2.5 metres (6.6–8.2 ft) long, with an elongated neck and tall spines on its vertebrae. Unlike other quadrupedal Triassic reptiles, the limbs and shoulders of Yarasuchus were slender, and more like those of ornithodirans.
Dongusuchus is an extinct genus of archosaur. Fossils have been found from the Donguz Formation outcropping on the banks of the Donguz River in the Orenburg Oblast of Russia. They are associated with a fossil assemblage called the Eryosuchus Fauna, named after the capitosaurid Eryosuchus, the most common organism found from the assemblage. The locality dates back to the Anisian and early Ladinian stages of the Middle Triassic.
Procerosuchus is an extinct genus of loricatan archosaur. Fossils have been collected from the Late Triassic Santa Maria Formation in Geopark of Paleorrota, Rio Grande do Sul, Brazil, which is Carnian in age. The genus was first described by the German paleontologist Friedrich von Huene in 1942.
Stagonosuchus is an extinct genus of loricatan, or possibly a species of Prestosuchus. Fossils have been found from the Late Triassic Manda Formation in Tanzania that are Anisian in age.
Poposauroidea is a clade of advanced pseudosuchians. It includes poposaurids, shuvosaurids, ctenosauriscids, and other unusual pseudosuchians such as Qianosuchus and Lotosaurus. It excludes most large predatory quadrupedal "rauisuchians" such as rauisuchids and "prestosuchids". Those reptiles are now allied with crocodylomorphs in a clade known as Loricata, which is the sister taxon to the poposauroids in the clade Paracrocodylomorpha. Although it was first formally defined in 2007, the name "Poposauroidea" has been used for many years. The group has been referred to as Poposauridae by some authors, although this name is often used more narrowly to refer to the family that includes Poposaurus and its close relatives.
Aphanosauria is an extinct group of reptiles distantly related to dinosaurs. They are at the base of a group known as Avemetatarsalia, one of two main branches of archosaurs. The other main branch, Pseudosuchia, includes modern crocodilians. Aphanosaurs possessed features from both groups, indicating that they are the oldest and most primitive known clade of avemetatarsalians, at least in terms of their position on the archosaur family tree. Other avemetatarsalians include the flying pterosaurs, small bipedal lagerpetids, herbivorous silesaurids, and the incredibly diverse dinosaurs, which survive to the present day in the form of birds. Aphanosauria is formally defined as the most inclusive clade containing Teleocrater rhadinus and Yarasuchus deccanensis but not Passer domesticus or Crocodylus niloticus. This group was first recognized during the description of Teleocrater. Although only known by a few genera, Aphanosaurs had a widespread distribution across Pangaea in the Middle Triassic. They were fairly slow quadrupedal long-necked carnivores, a biology more similar to basal archosaurs than to advanced avemetatarsalians such as pterosaurs, lagerpetids, and early dinosaurs. In addition, they seemingly possess 'crocodile-normal' ankles, showing that 'advanced mesotarsal' ankles were not basal to the whole clade of Avemetatarsalia. Nevertheless, they possessed elevated growth rates compared to their contemporaries, indicating that they grew quickly, more like birds than other modern reptiles. Despite superficially resembling lizards, the closest modern relatives of aphanosaurs are birds.
