Eoraptor is a genus of small, lightly built, basal sauropodomorph dinosaur. One of the earliest-known dinosaurs and one of the earliest sauropodomorphs, it lived approximately 231 to 228 million years ago, during the Late Triassic in Western Gondwana, in the region that is now northwestern Argentina. The type and only species, Eoraptor lunensis, was first described in 1993, and is known from an almost complete and well-preserved skeleton and several fragmentary ones. Eoraptor had multiple tooth shapes, which suggests that it was omnivorous. Eoraptor was 1.5 feet (0.46 m) tall and 3 feet (0.91 m) long.
Unaysaurus is a genus of unaysaurid sauropodomorph herbivore dinosaur. Discovered in southern Brazil, in the geopark of Paleorrota, in 1998, and announced in a press conference on Thursday, December 3, 2004, it is one of the oldest dinosaurs known. It is closely related to plateosaurid dinosaurs found in Germany, which indicates that it was relatively easy for species to spread across the giant landmass of the time, the supercontinent of Pangaea.
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.
Guaibasaurus is an extinct genus of basal saurischian dinosaur known from the Late Triassic Caturrita Formation of Rio Grande do Sul, southern Brazil. Most analyses recover it as a sauropodomorph, although there are some suggestions that it was a theropod instead. In 2016 Gregory S. Paul estimated it at 2 meters and 10 kg, whereas in 2020 Molina-Pérez and Larramendi listed it at 3 meters and 35 kg.
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.
Exaeretodon is an extinct genus of fairly large, low-slung traversodontid cynodonts from the southern parts of Pangea. Four species are known, from various formations. E. argentinus is from the Carnian-age Cancha de Bochas Member of the Ischigualasto Formation in the Ischigualasto-Villa Unión Basin in northwestern Argentina. E. major and E. riograndensis are from the Carnian-age portion of the Santa Maria Formation of the Paraná Basin in southeastern Brazil. E. statisticae is from the Carnian-age Lower Maleri Formation of India.
The Ischigualasto Formation is a Late Triassic geological formation in the Ischigualasto-Villa Unión Basin of southwestern La Rioja Province and northeastern San Juan Province in northwestern Argentina. The formation dates to the late Carnian and early Norian stages of the Late Triassic, according to radiometric dating of ash beds.
The Caturrita Formation is a rock formation found in Rio Grande do Sul, Brazil. Its sediments were deposited in the Paraná Basin. The formation is from the Upper Triassic and forms part of the Santa Maria Supersequence in the upper section of the Rosário do Sul Group.
Saturnaliidae is a family of basal sauropodomorph dinosaurs found in Brazil, Argentina and possibly Zimbabwe. It is not to be confused with Saturnalidae, a family of radiolarian protists.
Gomphodontosuchinae is a subfamily of Triassic traversodontid cynodonts. It includes the genera Gomphodontosuchus, Exaeretodon, Santagnathus, Siriusgnathus, Menadon, Proexaeretodon,Protuberum, Ruberodon and Scalenodontoides.
Pampadromaeus is an extinct genus of basal sauropodomorph dinosaurs known from the Late Triassic (Carnian) Santa Maria Formation of the Paraná Basin in Rio Grande do Sul, southern Brazil.
Botucaraitherium is an extinct genus of prozostrodontian cynodonts from the early Norian Riograndia Assemblage Zone in the Candelária Formation of the Paraná Basin in southeastern Brazil. It is known from a single type species, Botucaraitherium belarminoi. The genus name is derived from the Botucaraí Hill, which dominates the landscape of Candelária, Rio Grande do Sul. The species epithet honors Belarmino Stefanello, a volunteer at the Museu Municipal Aristides Carlos Rodrigues, who found the fossil.
Buriolestes is a genus of early sauropodomorph dinosaurs from the Late Triassic Santa Maria Formation of the Paraná Basin in southern Brazil. It contains a single species, B. schultzi, named in 2016. The type specimen was found alongside a specimen of the lagerpetid dinosauromorph Ixalerpeton.
Macrocollum is a genus of unaysaurid sauropodomorph dinosaur that lived during the Late Triassic period in what is now Brazil. It is one of the oldest dinosaurs known.
Nhandumirim is a genus of basal sauropodomorph dinosaur from the Carnian age of Late Triassic Brazil. It is currently considered a saturnaliid sauropodomorph. The type and only species, Nhandumirim waldsangae, is known from a single immature specimen including vertebrae, a chevron, pelvic material, and a hindlimb found in the Santa Maria Formation in Rio Grande do Sul.
The Candelária Formation, in other literature also referred to as Candelária Sequence, is a sedimentary formation of the Santa Maria Group in the Paraná Basin in Rio Grande do Sul, southeastern Brazil. The formation dates to the Carnian of the Late Triassic, locally referred to as Tuvalian, from 231.4 to approximately 222 Ma.
Erythrovenator is a genus of basal theropod dinosaurs from the Late Triassic of Rio Grande so Sul, Brazil. The genus contains a single species, Erythrovenator jacuiensis.
Bonacynodon is an extinct genus of cynodonts that lived in what is now southern Brazil during the Triassic period. The genus is monotypic, containing only the type species Bonacynodon schultzi. B. schultzi is known from two specimens, consisting of two partial skulls and some badly preserved parts of the postcranium. Both specimens were recovered from the Pinheiros-Chiniquá Sequence, part of the Santa Maria Supersequence of the Paraná Basin. This sequence preserves a faunal association known as the Dinodontosaurus Assemblage Zone, which contains numerous other species of cynodonts, dicynodonts and reptiles. Bonacynodon was a small, likely insectivorous cynodont, whose length has been estimated at around 30 centimetres (12 in). It can be distinguished from other cynodonts by its large, serrated (saw-like) canine teeth. Together with the genus Probainognathus of Argentina, it made up the family Probainognathidae, one of the earliest-diverging lineages of the clade Probainognathia. It was a fairly close relative of mammals, the only group of cynodonts alive today.
Scalenodontoides is an extinct genus of Traversodontidae, a family of herbivorous cynodonts. It lived during the Late Triassic in what is now South Africa. Its type species is Scalenodontoides macrodontes. It was named in 1957 by A. W. Crompton and F. Ellenberger. Arctotraversodon plemmyrodon was originally classified as a species of Scalenodontoides, but was given its own genus in 1992. It is found in the Scalenodontoides Assemblage Zone of the Elliot Formation, which is named for it. It is one of the geologically youngest traversodontids, alongside the putative traversodontid Boreogomphodon. It is closely related to Exaeretodon and Siriusgnathus, but is distinguished by the presence of a shelf-like expansion of its parietal called the nuchal table. Though the largest known complete skull is only 248 millimetres (9.8 in) long, it may have been the largest non-mammalian cynodont, as an incomplete snout would have belonged to a specimen with an estimated skull length of 617 millimetres (24.3 in).
Gamatavus is a genus of silesaurid dinosauriform from the Middle Triassic Santa Maria Formation of Dilermando de Aguiar Municipality, Brazil. The genus contains a single species, G. antiquus, known from a partial ilium. Gamatavus represents the oldest silesaurid known from South America.
Rio Grande do Sul 
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