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.
Etymology The formation received this name, because Caturrita is a neighbourhood (barrio) of Santa Maria. Formação Santa Maria , (in Portuguese) Paleoformações, (in Portuguese) In Portuguese caturrita also refers to the monk parakeet.
Stratigraphy The sediments of the Caturrita Formation belong to the second unit of the Santa Maria Supersequence and overlie the Alemoa Member of the Santa Maria Formation. The clayey sediments of the Alemoa Member gradually give way to the more sandy, rarely conglomeratic, Caturrita Formation, which finishes with an unconformity. After this erosional event follow the Rhaetian sediments of the Mata Sandstone, the third unit of the Santa Maria Supersequence.
The Caturrita Formation was once regarded as a member of the stratigraphically higher Botucatu FormationBortoluzzi, C.A. 1974. Contribuição à Geologia da Região de Santa Maria, Rio Grande do Sul, Brasil. Pesquisas, 4 (1):7-86 or was expanded to include the Mata Sandstone.Andreis, R.R.; Bossi, G.E. & Montardo, D.K. 1980. O Grupo Rosário do Sul (Triássico) no Rio grande do Sul. In: CONGRESSO BRASILEIRO DE GEOLOGIA,31, Balneário 16 Camboriú, 1980. Anais... Balneário de Camboriú, SBG, v. 2, p.659-673.
The Caturrita Formation reaches a maximum thickness of 60 meters, but generally oscillates around values of 30 meters.
Age Until 2018 no absolute ages had been determined, but the formation was most commonly assigned to a late Carnian to early Norian age on paleontological grounds. However, Rhaetian or even Early Jurassic age of this unit was also advocated in the literature. A U-Pb (Uranium decay) dating found that the Caturrita Formation dated around 225.42 million years ago, putting it less than 10 million years younger than the Santa Maria and Ischigualasto Formations, from where the earliest dinosaurs are known.
Geographical occurrence
Outcrops of the Caturrita Formation are found in the Brazilian state of Rio Grande do Sul. From the town of Taquari they follow for 250 kilometers a thin band in the central part of the state in an east-westerly fashion right up to Mata.
Depositional environment The sediments of the Caturrita Formation belong to the upper section of the Santa Maria Supersequence. In terms of sequence stratigraphy they are equivalent to a highstand systems tract. The scarlet, ephemeral, mainly clayey fluvio-lacustrine deposits of the Alemoa Member gradually cede to more sandy,Zerfass, H.; Lavina, E.L.; Schultz, C.L.; Garcia, A.J.V.; Faccini, U.F. & Chemale Jr., F. 2003. Sequence stratigraphy of continental Triassic strata of Southernmost Brazil: a contribution to Southwestern Gondwana palaeogeography and palaeoclimate. Sedimentary Geology, 161:85-105. occasionally gravelly deposits of a braided river-system that was operational all-year-round. These deposits of the Caturrita Formation settled out in an alluvial flood-plain. The changeover in sedimentary facies was accompanied by a climatic change to more humid conditions.Holz, M. und Scherer, C.M.S., 2000, Sedimentological and paleontological evidence of paleoclimatic change during the Southbrazilian Triassic: the register of a global trend towards a humid paleoclimate: Zentralblatt für Geologie und Paläontologie, Teil I, v. 11-12, p. 1589-1609.
The sediments are of continental nature (red beds) and form massive sandstone and siltstone bodies.Rubert, R. R. & Schultz, C. L. 2004. — Um novo horizonte de correlação para o Triássico Superior do Rio Grande do Sul. Pesquisas em Geociências 31: 71-88.
Vertebrate fauna The Caturrita Formation contains a biozone for tetrapods, the so-called "Ictidosauria Assemblage Zone″ Ca-1.Oliveira É. V. 2006. — Reevaluation of Therioherpeton cargnini Bonaparte & Barberena, 1975 (Probainognathia, Therioherpetidae) from the Upper Triassic of Brazil. Geodiversitas 28 (3) : 447-465.Ictidosaurs are tritheledontid cynodonts, a sister group of the mammals. This is the reason, why this biozone recently has been renamed as "Mammaliamorpha Cenozone" to underline the importance of the cynodont fossils.Soares, M.B. & Schultz, C.L., 2006. Proposta de nova denominação para a Cenozona de Ictidosauria, do Triássico Superior (Formação Caturrita) do Rio Grande do Sul. V Simpósio Brasileiro de Paleontologia de Vertebrados, Boletim de Resumos, p. 41, Santa Maria, RS, 2006. The Caturrita Formation also hosts the stratigraphic marker level "Jachaleria"Schultz. C.L.; Scherer, C.M.S. & Barberena, M.C. 1994. Uma nova proposta de zoneamento estratigráfi co para o Triássico Superior Sul-Rio-Grandense. In: Congresso Brasileiro de Geologia, 38, Camboriú - SC, 1994. Boletim de Resumos, p. 107-108. named after the dicynodont Jachaleria candelariensis. Dinosaurs and other vertebrates have been discovered as well.
In 1998 tracks of prosauropods have been found near Faxinal do Soturno that were most likely caused by Unaysaurus tolentinoi.Rafael Costa Da Silva, Ismar De Souza Carvalho, Cibele Schwanke, 2006. Vertebrate dinoturbation from the Caturrita Formation (Late Triassic, Paraná Basin), Rio Grande do Sul State, Brazil. Gondwana Research 11 (2007) 303–310.
The fossil finds are concentrated around three major areas: Santa Maria and northern surroundings (Água Negra) Faxinal do Soturno Candelária and surroundings (Linha São Luis)
The following taxa have been discovered so far in the Caturrita Formation:
Synapsids Synapsids of the Caturrita Formation Genus Species Location Stratigraphic position Material Notes ImagesBotucaraitheriumB. belarminoiSesmaria do PinhalA mammaliamorph cynodontBrasilitheriumB. riograndensisSynonym of Brasilodon quadrangularisBrasilodonB. quadrangularisLinha São Luiz, Sesmaria do PinhalA mammaliamorph cynodontIrajatheriumI. hernandeziLinha São Luiz, Sesmaria do PinhalA tritheledontid cynodontJachaleriaJ. candelariensisSesmaria do PinhalA stahleckeriid dicynodontcf. Jachaleriacf. J. candelariensisAlto Guarda Mor siteA stahleckeriid dicynodontMinicynodonM. maieriSynonym of Brasilodon quadrangularisRiograndiaR. guaibensisLinha São Luiz, Sesmaria do PinhalA tritheledontid cynodontTraversodontidae indet.IndeterminateSesmaria do Pinhal, Sacisaurus site
Dinosaurs
Unnamed prosauropod genus present in Rio Grande do Sul, Brazil.
Dinosaurs of the Caturrita Formation Genus Species Location Stratigraphic position Material Notes ImagesEubrontesIndeterminateRio Grande do Sul, Brazil.Two isolated footprintsAn ichnotaxon; footprints of large theropod dinosaurs.GuaibasaurusWeishampel, David B; et al. (2004). "Dinosaur distribution (Late Triassic, South America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 527–528. .G. candelariensisRio Grande do Sul, Brazil.Linha São Luiz"Partial postcranial skeleton and a fragmentary hindlimb.""Table 2.1," in Weishampel, et al. (2004). Page 26.SauropodomorphSauropodomorpha indet.IndeterminateRio Grande do Sul, Brazil"An incomplete right ilium, uninformative vertebral remains and other indeterminate fragments, plus four isolated and incomplete bones including a possible pubis, an ischium, a possible tibia and a metatarsal IV."An indeterminate sauropodomorph of uncertain phylogenetic placement, probably "closer to Plateosauria (...) than to Saturnalia-like basal–most sauropodomorphs".Sauropodomorpha indet.IndeterminateRio Grande do Sul, Brazil"Three incomplete dinosaur specimens, an isolated sacral vertebra, an articulated left pubis–ischium and an isolated right ischium."An indeterminate sauropodomorph of uncertain phylogenetic placement, "probably more primitive than typical 'prosauropods' from the Norian-Early Jurassic".UnaysaurusU. tolentinoiRio Grande do Sul, BrazilSauropodomorph
Other tetrapods
Misc tetrapods of the Caturrita Formation Genus Species Location Stratigraphic position Material Notes ImagesCargniniaC. enigmaticaRio Grande do Sul, BrazilLepidosaurClevosaurusC. brasiliensisSphenodontFaxinalipterusF. minimusRio Grande do Sul, BrazilA lagerpetidMaeharyM. bonaparteiRio Grande do Sul, BrazilThe earliest diverging member of PterosauromorphaProterochampsaProterochampsidSoturniaS. caliodonProcolophonianSacisaurusS. agudoensisRio Grande do Sul, BrazilSilesauridStereospondyli indet.IndeterminateRio Grande do Sul, BrazilAn incomplete interclavicleAn indeterminate stereospondyl temnospondyl.TeyumbaitaT. sulcognathusRio Grande do Sul, Brazil"Two nearly complete skulls and a partial skull."RhynchosaurPhytosauria indet.https://www.tandfonline.com/doi/pdf/10.1671/0272-4634%282003%29023%5B0464%3AAPFTUT%5D2.0.CO%3B2Indeterminate, possible recognized as cf. ParasuchusBotucaraí HillFragments parts of the lower jawAn indeterminate Phytosauria.
See also
Santa Maria Formation List of dinosaur-bearing rock formations Laguna Colorada Formation Elliot Formation
References
Bibliography Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. .
Further reading J. F. Bonaparte, J. Ferigolo, and A. M. Ribeiro. 1999. A new early Late Triassic saurischian dinosaur from Rio Grande do Sol state, Brazil. In Y. Tomida, T. H. Rich, and P. Vickers-Rich (eds.), Proceedings of the Second Gondwanan Dinosaur Symposium, National Science Museum Monographs 15:89-109 G. Brea, J. F. Bonaparte, C. L. Schultz and A. G. Martinelli. 2005. A new specimen of Guaibasaurus candelariensis (basal Saurischia) from the Late Triassic Caturrita Formation of southern Brazil. In A. W. A. Kellner, D. D. R. Henriques, and T. Rodrigues (eds.), II Congresso Latino-Americano de Paleontologia de Vertebrados, Boletim de Resumos. Museum Nacional/UFRJ, Rio de Janeiro 55-56 R. Costa, I. d. S. Carvalho, and C. Schwanke. 2003. Icnofósseis de vertebrados na Formação Caturrita (Neotriássico da Bacia do Paraná) no Estado do Rio Grande do Sul, Brasil [Vertebrate ichnofossils from the Caturrita Formation (Late Triassic of the Paraná Basin) in Rio Grande do Sul State, Brazil]. XVIII Congresso Brasileiro de Paleontologia: A Paleontologia e Suas Aplicações, 13–18 July 2003. Sociedade Brasileira de Paleontologia, Universidade de Brasília. Boletim de Resumos 110-111 E.-E. Kischlat and M. C. Barbarena. 1999. Triassic Brazilian dinosaurs: new data. I Simpósio Brasileiro de Paleontologia de Vertebrados. Paleontologia em Destaque 26:56 M. C. Langer and J. Ferigolo. 2005. The first ornithischian body-fossils in Brazil: Late Triassic (Caturrita Formation) of Rio Grande do Sul. In A. W. A. Kellner, D. D. R. Henriques, and T. Rodrigues (eds.), II Congresso Latino-Americano de Paleontologia de Vertebrados, Boletim de Resumos. Museum Nacional/UFRJ, Rio de Janeiro 146-147 A. G. Martinelli, J. F. Bonaparte, C. L. Schultz and R. Rubert. 2005. A new tritheledontid (Therapsida, Eucynodontia) from the Late Triassic of Rio Grande do Sul (Brazil) and its phylogenetic relationships among carnivorous non-mammalian eucynodonts. Ameghiniana 42(1):191-208 R. T. Müller, A. A. S. da Rosa, L. R. Silva, A. S. S. Aires, C. P. Pacheco, A. E. B. Pavanatto, and S. Dias-da-Silva. 2015. Wachholz, a new exquisite dinosaur-bearing fossiliferous site from the Upper Triassic of southern Brazil. Journal of South American Earth Sciences 61:120-128 R. C. da Silva, R. Barboni, T. Dutra, M. M. Godoy, and R. B. Binotto. 2012. Footprints of large theropod dinosaurs and implications on the age of Triassic biotas from Southern Brazil. Journal of South American Earth Sciences