Santa Maria Formation

Santa Maria Formation
Stratigraphic range: Carnian
~237–228 Ma
The Schoenstatt Outcrop of the Santa Maria Formation, which is the type locality of Dagasuchus santacruzensis. Photographed around 2006.
TypeGeological formation
Unit ofRosário do Sul Group
Sub-unitsPasso das Tropas & Alemoa Members
UnderliesCaturrita Formation
OverliesSanga do Cabral Formation
Location
Coordinates29°41′42″S 53°47′43″W / 29.695042°S 53.795403°W / -29.695042; -53.795403
Region Rio Grande do Sul
Country Brazil
ExtentParaná Basin
Santa Maria Formation. Source: UFSM

The Santa Maria Formation is a sedimentary rock formation found in Rio Grande do Sul, Brazil. It is primarily Carnian in age (Late Triassic), 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.

The Santa Maria Formation makes up the majority of the Santa Maria Supersequence, which extends through the entire Late Triassic. The Santa Maria Supersequence is divided into four geological sequences, separated from each other by short unconformities. The first two of these sequences (Pinheiros-Chiniquá and Santa Cruz sequences) lie entirely within the Santa Maria Formation, while the third (the Candelária sequence) is shared with the overlying Norian-age Caturrita Formation. The fourth and youngest sequence (the Mata sequence) is equivalent to the Rhaetian-age Mata Sandstone.

The oldest sequence in the formation is the Pinheiros-Chiniquá Sequence (latest Ladinian-earliest Carnian, ~237 Ma), which is biostratigraphically equivalent to the Dinodontosaurus Assemblage Zone. It is followed by the shorter Santa Cruz Sequence (early Carnian-middle Carnian, ~236 Ma), biostratigraphically equivalent to the Santacruzodon Assemblage Zone.

The final sequence, which is only partially present within the formation, is the Candelária Sequence (middle Carnian-latest Carnian, ~233-228 Ma). The lower portion of this sequence, coinciding with the upper part of the Santa Maria Formation, is equivalent to the Hyperodapedon Assemblage Zone.The Hyperodapedon Assemblage Zone is itself subdivided into Hyperodapedon Acme Zone (most of the zone, where the rhynchosaur Hyperodapedon is widely reported) and Exaeretodon Zone (restricted to about three known and sampled localities, where rhynchsaurs are almost completely absent, but the traversodontid cynodont Exaeretodon is widely reported). These subdivisions are also known as Lower and Upper Hyperodapedon Assemblage Zone, respectively.

U-Pb radiometric dating of Cerro da Alemoa (the type locality of Saturnalia tupiniquim) in the Upper portion of the Santa Maria Formation found an estimated age of 233.23±0.73 million years ago, putting that locality 1.5 million years older than the Ischigualasto Formation and younger than Los Chañares Formation. The Santa Maria and Ischigualasto formations are approximately equal as having the earliest dinosaur localities.

Vertebrate paleofauna

Most of the information below was included on a revision of the Triassic faunal successions of the Paraná Basin, southern Brazil by Schultz et al. (2020).

Temnospondyls

Temnospondyls of the Santa Maria Formation
Genus Species Location Stratigraphic position Material Notes Images
Compsocerops C. sp. Restinga Sêca Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone A partial skull A chigutisaurid temnospondyl

Synapsids

Dicynodonts

Dicynodonts of the Santa Maria Formation
Genus Species Location Stratigraphic position Material Notes Images
Dinodontosaurus D. pedroanum São Pedro do Sul, Candelária, Dona Francisca, Bom Retiro, Vale Verde, Novo Cabrais, Bom Retiro do Sul, Dilermando de Aguiar Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone Cranial and postcranial remains A kannemeyeriiform dicynodont
Stahleckeria S. potens Dona Francisca, Candelária Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone Cranial and postcranial remains A stahleckeriid dicyndont

Cynognathians

Cynognathians of the Santa Maria Formation
Genus Species Location Stratigraphic position Material Notes Images
Exaeretodon E. major São Pedro do Sul Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone Cranial and postcranial remains A traversodontid cynodont
E. riograndensis Agudo, Santa Maria Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Exaeretodon Zone Cranial and postcranial remains A traversodontid cynodont
Gomphodontosuchus G. brasiliensis Santa Maria Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone Cranial remains A traversodontid cynodont
Luangwa L. sudamericana Vera Cruz, Candelária Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone Cranial remains A traversodontid cynodont
Massetognathus M. ochagavie Bom Retiro, Vale Verde, Dona Francisca Lower and Middle Santa Maria Formation, Alemoa Member, Santa Cruz nad Pinheiros-Chiniquá Sequences, Santacruzodon Assemblage Zone and Dinodontosaurus Assemblage Zone Cranial and postcranial remains A traversodontid cynodont
Menadon M. besairiei Santa Cruz Middle Santa Maria Formation, Alemoa Member, Santa Cruz Sequence, Santacruzodon Assemblage Zone Cranial remains A traversodontid cynodont
Protuberum P. cabralensis Paraíso do Sul, Novo Cabrais Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone Partial articulated skeleton including skull, vertebrae and ribs A traversodontid cynodont
Santacruzodon S. hopsoni Santa Cruz Middle Santa Maria Formation, Alemoa Member, Santa Cruz Sequence, Santacruzodon Assemblage Zone Cranial remains A traversodontid cynodont
Santagnathus S. mariensis Hyperodapedon Assemblage Zone Numerous cranial and postcranial remains A traversodontid cynodont
Scalenodon S. ribeiroae Agudo Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone Cranial remains A traversodontid cynodont
Traversodon T. stahleckeri São Pedro do Sul Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone Cranial remains A traversodontid cynodont

Probainognathians

Probainognathians of the Santa Maria Formation
Genus Species Location Stratigraphic position Material Notes Images
Alemoatherium A. huebneri Santa Maria Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone A partial dentary A prozostrodontian cynodont
Aleodon A. cromptoni Vale Verde, Candelária, Bom Retiro do Sul, Novo Cabrais Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone Cranial and postcranial remains A chiniquodontid cynodont
Bonacynodon B. schultzi Candelária Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone Cranial remains A probainognathid cynodont
Candelariodon C. barberenai Candelária Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone A partial mandible having some complete teeth A basal probainognathian cynodont
Charruodon C. tetracuspidatus Candelária Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone A partial dentary A basal probainognathian cynodont
Chiniquodon C. theotonicus São Pedro do Sul Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone Several cranial remains A chiniquodontid cynodont
C. sp. Santa Cruz Middle Santa Maria Formation, Alemoa Member, Santa Cruz Sequence, Santacruzodon Assemblage Zone Cranial and postcranial remains A chiniquodontid cynodont
Protheriodon P. estudianti Dona Francisca Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone Cranial remains A basal probainognathian cynodont
Prozostrodon P. brasiliensis Santa Maria, São João do Polêsine Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone Cranial remains A prozostrodontian cynodont
Santacruzgnathus S. abdalai Santa Cruz Middle Santa Maria Formation, Alemoa Member, Santa Cruz Sequence, Santacruzodon Assemblage Zone Cranial remains A prozostrodontian cynodont
Therioherpeton T. cargnini Santa Maria Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone Cranial remains A prozostrodontian cynodont
Trucidocynodon T. riograndensis Agudo Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Exaeretodon Zone Cranial and postcranial elements of an almost complete skeleton and an additional large skull An ecteniniid cynodont

Reptiles

Pseudosuchians

Pseudosuchians of the Santa Maria Formation
Genus Species Location Stratigraphic position Material Notes Images
Aetobarbakinoides A. brasiliensis Santa Maria Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone Partial postcranial skeleton A aetosaur
Aetosauroides A. scagliai Santa Maria, São João do Polêsine, São Pedro do Sul Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone An almost complete skull and incomplete postcranial elements An aetosaur
Archeopelta A. arborensis São Pedro do Sul Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone Cranial and postcranial elements An erpetosuchid
Dagasuchus D. santacruzensis Santa Cruz do Sul Middle Santa Maria Formation, Alemoa Member, Santa Cruz Sequence, Santacruzodon Assemblage Zone An ilium and a pair of ischia A loricatan
Decuriasuchus D. quartacolonia Dona Francisca Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone Assemblage of several individuals, which together preserved virtually all the skeleton A loricatan
Dynamosuchus D. collisensis Agudo Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Exaeretodon Zone Semi-articulated partial skull and disarticulated fragmentary postcranial skeleton An ornithosuchid
Pagosvenator P. candelariensis Candelária Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone Poorly preserved skull and cervical elements An erpetosuchid
"Polesinesuchus" "P. aurelioi" São João do Polêsine Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone Several postcranial elements An immature aetosaur, possible synonym of Aetosauroides scagliai
Prestosuchus P. chiniquensis
"P. loricatus""Karamuru vorax"
Candelária, Dona Francisca, São Pedro do Sul, and possibly Vale Verde ("K. vorax") Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone Virtually all the skeleton is known A loricatan
Procerosuchus P. celer São Pedro do Sul Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone Postcranial elements A loricatan
Rauisuchus R. tiradentes Santa Maria Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone Incomplete skeleton including skull elements, several vertebrae and partial hindlimb A loricatan
Unnamed loricatan - Santa Maria Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone Specimen UFSM 11617, an almost complete right maxilla A loricatan

Avemetatarsalians

Avemetatarsalians of the Santa Maria Formation
Genus Species Location Stratigraphic position Material Notes Images
Amanasaurus A. nesbitti Restinga Sêca Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone Two partial femora A silesaurid
Bagualosaurus B. agudoensis Agudo Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Exaeretodon Zone Almost complete skull with lower jaws, several vertebrae, partial pelvic girdle, partial hindlimbs A basal sauropodomorph
Buriolestes B. schultzi São João do Polêsine Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone Parts of the skull, vertebrae, left forelimb, and left hindlimb The basalmost sauropodomorph
Gamatavus G. antiquus Dilermando de Aguiar Lower Santa Maria Formation (‘Picada do Gama’ site), Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone A partial right ilium; a partial left femur and four incomplete vertebrae found in association with the holotype may belong to Gamatavus, but they were not assigned The oldest known silesaurid from South America
Gnathovorax G. cabreirai São João do Polêsine Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone A complete semi-articulated skeleton, part of a multiataxic fossil assemblage, including two cynodonts and two rhynchosaurs A herrerasaurid
Ixalerpeton I. polesinensis São João do Polêsine Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone Partial skull including a partial maxilla and both dentaries, most of the presacral vertebrae, two sacral vertebrae, several caudal verterae and associated chevrons, scapula and humerus, femora of at least two individuals, and tibia A basal lagerpetid
Nhandumirim N. waldsangae Santa Maria Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone Some vertebrae, partial pelvic girdle, partial hindlimb A juvenile saturnaliid sauropodomorph
Pampadromaeus P. barberenai Agudo Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Exaeretodon Zone Almost complete skull and lower jaws, several vertebrae, partial pectoral girdle, partial forelimb, partial pelvic girdle, partial hindlimb A basal sauropodomorph
Saturnalia S. tupinquim Santa Maria Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone Three partial skeleton, including partial skull and lower jaw, complete cervical, dorsal and partial caudal vertebral series, pectoral girdle, partial forelimb, pelvic girdle, partial hindlimb A basal sauropodomorph
Saturnalia tupiniquim
Saturnalia tupiniquim
Spondylosoma S. absconditum São Pedro do Sul Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone Several postcranial remains An aphanosaurian
Staurikosaurus S. pricei Santa Maria Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone Partial postcranial skeleton with mandible A basal herrerasaurid
Venetoraptor V. gassenae São João do Polêsine Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone A lagerpetid.
Unnamed dinosauromorph - Dona Francisca Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone Specimen CAPPA/UFSM 0282, a complete, but poorly preserved right femur The oldest dinosauromorph from South America
Unnamed herrerasaurid - Santa Maria Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone Specimen UFSM 11330, comprised by partial cranial and postcranial remains The largest Triassic dinosaur skeleton found in Rio Grande do Sul state so far
Unnamed lagerpetid - Santa Maria Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone Specimen UFSM 11611 (partial left femur) A basal lagerpetid distinct from Ixalerpeton
Unnamed silesaurid - Santa Maria Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone Specimen UFSM 11579, comprised by cranial and postcranial remains A silesaurid

Other reptiles

Other reptiles of the Santa Maria Formation
Genus Species Location Stratigraphic position Material Notes Images
Barberenasuchus B. brasiliensis Novo Cabrais Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone Poorly preserved skull and axis vertebra An archosauriform of uncertain affinities
Brasinorhynchus B. mariantensis Bom Retiro do Sul Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone A complete skull, atlas, axis, third neck vertebra A stenaulorhynchine rhynchosaur archosauromorph
Candelaria C. barbouri Dona Francisca, Candelária, Novo Cabrais Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone Cranial and postcranial remains An owenetiid procolophonoid
Cerritosaurus C. binsfeldi Santa Maria Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone Badly preserved skull and postcranial elements A proterochampsid archosauriform
Clevosaurus C. hadroprodon Candelária Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Exaeretodon Zone Cranial remains A clevosaurid rhynchocephalian
Hyperodapedon H. sanjuanensis

H. mariensis?

H. huenei

Santa Maria, Agudo, Candelária, São João do Polêsine, Venâncio Aires, Restinga Sêca, São Pedro do Sul Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone Complete skulls, and most postcranial elements A hyperodapedontine rhynchosaur archosauromorph
Kuruxuchampsa K. dornellesi Middle Santa Maria Formation, Alemoa Member, Santa Cruz Sequence, Santacruzodon Assemblage Zone A proterochampsid archosauriform. Previously referred to Chanaresuchus
Macrocephalosaurus M. mariensis Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone A hyperodapedontine rhynchosaur archosauromorph. Sometimes referred to Hyperodapedon
Pinheirochampsa P. rodriguesi Lower Santa Maria Formation, Alemoa Member, Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone A proterochampsid archosauriform
Proterochampsa P. nodosa Candelária Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone Skull and partial postcranial elements A proterochampsid archosauriform
Rhadinosuchus R. gracilis Santa Maria Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Hyperodapedon Acme Zone Badly preserved skull and postcranial elements A proterochampsid archosauriform
Stenoscelida S. aurantiacus Agudo Upper Santa Maria Formation, Alemoa Member, Candelária Sequence, Hyperodapedon Assemblage Zone, Exaeretodon Zone Almost complete and well preserved hind limb A proterochampsid archosauriform
Unnamed proterochampsid - Unknown Santa Maria Formation, Alemoa Member Badly preserved skull A proterochampsid archosauriform

Formations

See also


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