Caturrita Formation

Caturrita Formation Stratigraphic range: Carnian - Norian
Caturrita Formation. Source: UFSM
Type	Geological formation
Unit of	Santa Maria Supersequence
Underlies	Mata Sandstone
Overlies	Alemoa Member, Santa Maria Formation
Thickness	30 - 60 m
Lithology
Primary	sandstones, siltstones
Location
Coordinates	-29.695042, -53.795403
Region	Paleorrota  Rio Grande do Sul
Country	Brazil
Extent	250 km
Type section
Named for	Caturrita, barrio of Santa Maria
Geopark of Paleorrota

The Caturrita Formation is a rock formation found in Rio Grande do Sul, Brazil. Its sediments were deposited in the Paraná Basin. The formation most likely has a late Carnian to early Norian age (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. ^{[1] [2]} 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 Formation^[3] or was expanded to include the Mata Sandstone.^[4]

The Caturrita Formation reaches a maximum thickness of 60 meters, but generally oscillates around values of 30 meters.

Mata

Santa Maria

São
Pedro

São Sepé

Cachoeira

Candelária

Rio Pardo

Santa Cruz

Venâncio

Aceguá

Alegrete

Bagé

Rosário

São Gabriel

Caçapava

Geological formations in Rio Grande do Sul:
1) Serra Geral Formation, Cretaceous. 2) Botucatu Formation, Cretaceous. 3) Guará Formation, Jurassic. 4) Santa Maria Formation e Caturrita Formation, Triassic. 5) Sanga do Cabral Formation, Triassic. 6) Piramboia Formation, Permian. 7) Itararé Group, Permian.

 

Age

So far no absolute ages have been determined, but the formation is most commonly assigned to a late Carnian to early Norian age on paleontological grounds, i.e. an age range of about 220 to 215 million years BP. However, Rhaetian or even Early Jurassic age of this unit was also advocated in the literature.^[5]

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,^[6] 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.^[7]

The sediments are of continental nature (red beds) and form massive sandstone and siltstone bodies.^[8]

Vertebrate fauna

The Caturrita Formation contains a biozone for tetrapods, the so-called “Ictidosauria Assemblage Zone″ Ca-1.^[9]Ictidosaurs are trithelodontid 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.^[10] The Caturrita Formation also hosts the stratigraphic marker level “Jachaleria”^[11] 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.^[12]

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:

Color key Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon		Notes Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Synapsids

Synapsids of the Caturrita Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Brasilitherium	B. riograndensis					Exaeretodon
Brasilodon	B. quadrangularis
Exaeretodon
Irajatherium	I. hernandezi
Jachaleria	J. candelariensis
Minicynodon	M. maieri
Riograndia	R. guaibensis

Dinosaurs

Unnamed prosauropod genus present in Rio Grande do Sul, Brazil.^[13]

Dinosaurs of the Caturrita Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Eubrontes[5]	Indeterminate[5]	Rio Grande do Sul, Brazil.[5]		Two isolated footprints[5]	An ichnotaxon; footprints of large theropod dinosaurs.[5]	Guaibasaurus
Guaibasaurus[13]	G. candelariensis[13]	Rio Grande do Sul, Brazil.[13]		"Partial postcranial skeleton and a fragmentary hindlimb."[14]	Sauropodomorph
Sauropodomorpha indet.[15]	Indeterminate	Rio 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."[15]	An indeterminate sauropodomorph of uncertain phylogenetic placement, probably "closer to Plateosauria (...) than to Saturnalia–like basal–most sauropodomorphs".[15]
Sauropodomorpha indet.[16]	Indeterminate	Rio Grande do Sul, Brazil		"Three incomplete dinosaur specimens, an isolated sacral vertebra, an articulated left pubis–ischium and an isolated right ischium."[16]	An indeterminate sauropodomorph of uncertain phylogenetic placement, "probably more primitive than typical ‘prosauropods’ from the Norian-Early Jurassic".[16]
Unaysaurus	U. tolentinoi	Rio Grande do Sul, Brazil			Sauropodomorph

Other tetrapods

Undetermined phytosaur genus.

Misc tetrapods of the Caturrita Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Cargninia	C. enigmatica	Rio Grande do Sul, Brazil			Lepidosaur	Proterochampsa
Clevosaurus	C. brasiliensis				Sphenodont
Faxinalipterus	F. minima	Rio Grande do Sul, Brazil			Pterosaur
Proterochampsa					Proterochampsid
Soturnia	S. caliodon				Procolophonian
Sacisaurus	S. agudoensis	Rio Grande do Sul, Brazil			Silesaurid
Stereospondyli indet.[17]	Indeterminate	Rio Grande do Sul, Brazil		An incomplete interclavicle[17]	An indeterminate stereospondyl temnospondyl.[17]
Teyumbaita[18]	T. sulcognathus	Rio Grande do Sul, Brazil		"Two nearly complete skulls and a partial skull."	Rhynchosaur

See also

• Santa Maria Formation
• List of dinosaur-bearing rock formations

Footnotes

1. Formação Santa Maria, (in Portuguese)
2. Paleoformações, (in Portuguese)
3. Bortoluzzi, C.A. 1974. Contribuição à Geologia da Região de Santa Maria, Rio Grande do Sul, Brasil. Pesquisas, 4 (1):7-86
4. 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.
5. Rafael Costa da Silva, Ronaldo Barboni, Tânia Dutra, Michel Marques Godoy and Raquel Barros Binotto (2012). "Footprints of large theropod dinosaurs and implications on the age of Triassic biotas from Southern Brazil". Journal of South American Earth Sciences. in press. doi:10.1016/j.jsames.2012.06.017.
6. 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.
7. 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.
8. 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.
9. Oliveira É. V. 2006. — Reevaluation of Therioherpeton cargnini Bonaparte & Barberena, 1975 (Probainognathia, Therioherpetidae) from the Upper Triassic of Brazil. Geodiversitas 28 (3) : 447-465.
10. 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.
11. 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.
12. 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.
13. Weishampel, 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. ISBN 0-520-24209-2.
14. "Table 2.1," in Weishampel, et al. (2004). Page 26.
15. Jonathas S. Bittencourt, Luciano A. Leal, Max C. Langer & Sérgio A. K. Azevedo (2012). "An additional basal sauropodomorph specimen from the Upper Triassic Caturrita Formation, southern Brazil, with comments on the biogeography of plateosaurids". Alcheringa: An Australasian Journal of Palaeontology 36 (2): 269–278. doi:10.1080/03115518.2012.634111.
16. Jonathas Souza Bittencourt, Átila Augusto Stock da Rosa, Cesar Leandro Schultz and Max Cardoso Langer (2012). "Dinosaur remains from the ‘Botucaraí Hill’ (Caturrita Formation), Late Triassic of south Brazil, and their stratigraphic context". Historical Biology: An International Journal of Paleobiology. in press. doi:10.1080/08912963.2012.694881.
17. Sérgio Dias-da-Silva, Eliseu Vieira Dias & Cesar Leandro Schultz (2009). "First record of stereospondyls (Tetrapoda, Temnospondyli) in the Upper Triassic of Southern Brazil". Gondwana Research 15 (1): 131–136. doi:10.1016/j.gr.2008.07.002.
18. Felipe Chinaglia Montefeltro, Max Cardoso Langer and Cesar Leandro Schultz (2010). "Cranial anatomy of a new genus of hyperodapedontine rhynchosaur (Diapsida, Archosauromorpha) from the Upper Triassic of southern Brazil" (PDF). Earth and Environmental Science Transactions of the Royal Society of Edinburgh 101: 27–52. doi:10.1017/S1755691010009060.

References

• Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. ISBN 0-520-24209-2.

Coordinates: 29°41′42″S 53°47′43″W / 29.695042°S 53.795403°W