Santa María Formation

The Santa Maria Formation is a sedimentary rock formation found in Rio Grande do Sul, Brazil. It has a Late Anisian to Early Norian age (Early to Late Triassic), and is notable for its fossils of early dinosaurs and other dinosauromorphs, including the herrerasaurid Staurikosaurus, the basal sauropodomorphs Buriolestes and Saturnalia, and the lagerpetid Ixalerpeton. It received this name because it was discovered first in the city of Santa Maria, on the central region of Rio Grande do Sul state.Rio Grande do Sul.Junior synonym of ChiniquodonCandelariodonC. barberenaiRio Grande do Sul.A partial mandible having some complete teeth.A cynodont.ChiniquodonC. theotonicusExaeretodonE. riograndensisP. cabralensisSantacruzodonS. hopsoniRio Grande do Sul.Cranial remains.A traversodontid cynodont.TrucidocynodonT. riograndensisAn ecteniniid cynodont.A complete skull, atlas, axis, third neck vertebraChanaresuchusC. bonaparteiCandelária-Santa Cruz do Sul, Rio Grande do Sul.Disarticulated cranial and postcranial elements.A proterochampsid archosauromorphD. quartacoloniaA 'rauisuchian'/loricatan pseudosuchian archosaurH. mariensisPampadromaeusP. barberenaiAgudo, Rio Grande do SulAlmost complete skull and lower jaws, several vertebrae, partial pectoral girdle, partial forelimb, partial pelvic girdle, partial hindlimbA basal sauropodomorph dinosaurPolesinesuchus P. aurelioiAn aetosaur pseudosuchianP. loricatusSaturnalia S. tupinquimSanta Maria, Rio Grande do SulThree partial skeleton, including partial skull and lower jaw, complete cervical, dorsal and partial caudal vertebral series, pectoral girdle, partial forelimb, pelvic girdle, partial hindlimbA basal sauropodomorph dinosaurSpondylosoma S. absconditumSão Pedro do Sul, Rio Grande do SulSeveral postcranial remainsAn avemetatarsalian aphanosaurStaurikosaurus S. priceiSanta Maria, Rio Grande do SulPartial postcranial skeleton with mandibleA herrerasaurid dinosaurTeyuwasu T. barberenaiSanta Maria, Rio Grande do SulRight femur and tibia The Santa Maria Formation is a sedimentary rock formation found in Rio Grande do Sul, Brazil. It has a Late Anisian to Early Norian age (Early to Late Triassic), and is notable for its fossils of early dinosaurs and other dinosauromorphs, including the herrerasaurid Staurikosaurus, the basal sauropodomorphs Buriolestes and Saturnalia, and the lagerpetid Ixalerpeton. It received this name because it was discovered first in the city of Santa Maria, on the central region of Rio Grande do Sul state. The distinguished English paleontologist Arthur Smith Woodward determined the age of Santa Maria Formation dated Mesozoic Era, Upper Triassic period (about 220 million years). A U-Pb (Uranium decay) dating of a locality of the Upper portion of the Santa Maria Formation dated around 233.23±0.73 million years ago, putting that locality 1.5 million years older than the Ischigualasto Formation, instead being in the temporal range of the Los Chañares Formation, and making the two formations (Santa Maria and Ischigualasto) approximately equal as having the earliest dinosaur localities. The Santa Maria Formation is part of the Candelária Sequence, and is biostratigraphically subdivided into Dinodontosaurus (latest Ladinian-earliest Carnian), Santacruzodon (earliest Carnian-middle Carnian), and Hyperodapedon (middle Carnian-latest Carnian) Assemblage Zones (from the oldest to youngest). Moreover, the Hyperodapedon Assemblage Zone is subdivided into Hyperodapedon Acme Zone (most of the zone, where the rhynchosaur Hyperodapedon is widely reported) and Exaeretodon Sub-Zone (restricted to 3 known and sampled localities, where Hyperodapedon is almost absent, but the traversodontid cynodont Exaeretodon is widely reported). These subdivisions are also known as Lower and Upper Hyperodapedon Assemblage Zone, respetively.