Dinosaur remains are among the fossils that have been recovered from the Adamantina Formation.[1] According to some studies,[2][3][4][5] the Adamantina Formation dates from the Turonian to the Santonian stage (90-83.5 million years ago) of the late Cretaceous, other studies have found a much younger age - Campanian to Maastrichtian (83.5-66 million years ago) of the late Cretaceous.[6][7]
More recent studies lean into the latter category[8] and an unpublished article abstract revealed at the Society of Vertebrate Paleontology in 2017 also argues that the Allen Formation, Loncoche, and Los Alamitos Formation are all contemporaries and are no later than 72.1Ma in age.[9] A zircon was found dating to 87.8 Ma, so this represents a maximum age.[10]
Geological setting
During the Early Jurassic, the supercontinent Pangea started to drift apart due to the breakup of Gondwana and Laurasia.[11] The breakup of Gondwana caused the formation of the large Parana Basin. This basin has a size of ~1,100,000km2 and can be found not only in Brazil but also in Paraguay, Uruguay, and Argentina.[12] The separation of the supercontinent and the breakup of Brazil and Africa was accompanied by volcanism that caused large eruptions of flood basalts. These volcanic rocks formed the Serra Geral Formation which underlies the deposits of the Bauru Group.[12]
The Bauru Basin is a trough that, as Miall (1990) argues,[13] evolved due to “thermo-mechanical subsidence” during the Late Cretaceous, probably due to the breakup of Africa and India.[11] The sediments reach a thickness of up to ~300 m and consist mainly of siliciclastic sediments.[14] The Bauru Group can be subdivided into five different formations [12][15][16][17] from bottom to top: Caiua, Santo Anastacio, Adamantina, and Uberaba. Not all formations are equally well represented in the different states and differences occur according their sedimentary composition and therefore also in their naming.[12]
Very common. Several specimens - juvenile and adults – with skulls articulated to skeletons, and many isolated materials. Eggs clutches, eggshells, and coprolites were found also.
^ abWeishampel, David B; et al. (2004). "Dinosaur distribution (Late Cretaceous, South America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 600-604. ISBN0-520-24209-2.
^Turner, A.H.; Sertich, J.W. (2010). "Phylogenetic history of Simosuchus clarki (Crocodyliformes: Notosuchia) from the Late Cretaceous of Madagascar". Journal of Vertebrate Paleontology. 30 (6, Memoir 10): 177–236. Bibcode:2010JVPal..30S.177T. doi:10.1080/02724634.2010.532348. S2CID86737170.
^ abMarco Brandalise de Andrade; Reinaldo J. Bertini (2008). "A new Sphagesaurus (Mesoeucrocodylia: Notosuchia) from the Upper Cretaceous of Monte Alto City (Bauru Group, Brazil), and a revision of the Sphagesauridae". Historical Biology. 20 (2): 101–136. Bibcode:2008HBio...20..101B. doi:10.1080/08912960701642949. S2CID84879725.
^ abRabassa, J. (2014). Some concepts on Gondwana landscapes: long-term landscape evolution, genesis, distribution and age. In Gondwana Landscapes in southern South America (pp. 9-46). Springer Netherlands.
^Soares, P. C.; Landim, P. M. B.; Fulfaro, V. J.; Neto, A. S. (1980). "Ensaio de caracterização estratigráfica do Cretáceo no estado de São Paulo: Grupo Bauru". Revista Brasileira de Geociências. 10 (3): 177–185. doi:10.25249/0375-7536.1980177185 (inactive 2024-04-25).{{cite journal}}: CS1 maint: DOI inactive as of April 2024 (link)
^Souza Jr, J. J. (1984). O Grupo Bauru na porcao mais setentrional da Bacia Sedimentar do Paraná. In 33 Congresso Brasileiro de Geologia, Rio de Janeiro (Vol. 2, pp. 944-957).
^Dias-Brito, D., Musacchio, E. A., de Castro, J. C., Maranhão, M. S. A. S., Suárez, J. M., & Rodrigues, R. (2001). Grupo Bauru: uma unidade continental do Cretáceo no Brasil-concepções baseadas em dados micropaleontológicos, isotópicos e estratigráficos. Revue de Paléobiologie, 20(1), 245-304.
^Marinho, Thiago S.; Carvalho, Ismar S. (2009). "An armadillo-like sphagesaurid crocodyliform from the Late Cretaceous of Brazil". Journal of South American Earth Sciences. 27 (1): 36–41. Bibcode:2009JSAES..27...36M. doi:10.1016/j.jsames.2008.11.005.
^Fabiano V. Iori; Ismar S. Carvalho (2011). "Caipirasuchus paulistanus, a new sphagesaurid (Crocodylomorpha, Mesoeucrocodylia) from the Adamantina Formation (Upper Cretaceous, Turonian–Santonian), Bauru Basin, Brazil". Journal of Vertebrate Paleontology. 31 (6): 1255–1264. Bibcode:2011JVPal..31.1255I. doi:10.1080/02724634.2011.602777. S2CID128482509.
^Iori, F.V.; Carvalho, I.S. (2009). "Morrinhosuchus luziae, um novo Crocodylomorpha Notosuchia da Bacia Bauru, Brasil". Revista Brasileira de Geociências. 39 (4): 717–725. doi:10.25249/0375-7536.2009394717725 (inactive 2024-04-25).{{cite journal}}: CS1 maint: DOI inactive as of April 2024 (link)
^Silva, J.C. Jr.; Martinelli, A.G.; Iori, F.V.; Marinho, T.S.; Hechenleitner, E.M.; Langer, M.C. (2021). "Reassessment of Aeolosaurus maximus, a titanosaur dinosaur from the Late Cretaceous of Southeastern Brazil". Historical Biology: An International Journal of Paleobiology. 34 (3): 403–411. doi:10.1080/08912963.2021.1920016. S2CID235526860.
^"Table 13.1," in Weishampel, et al. (2004). Page 270.
^Yun-Hsin Wu, Luis M. Chiappe, David J. Bottjer, William Nava & Agustín G. Martinelli, Dental replacement in Mesozoic birds: evidence from newly discovered Brazilian enantiornithines, Scientific Reports volume 11, Article number: 19349 (2021)
^"Table 13.1," in Weishampel, et al. (2004). Page 269.
^Kellner, A.W.A.; Campos, D.A.; Azevedo, S.A.K.; et al. (2006). "On a new titanosaur sauropod from the Bauru Group, Late Cretaceous of Brazil". Boletim do Museu Nacional (Geologia). 74: 1–31.
^Santos, R. O.; Carvalho, A. B.; Zaher, H. (2023). "A new fossil frog (Lissamphibia: Anura) from the Late Cretaceous of Brazil and the early evolution of neobatrachians". Zoological Journal of the Linnean Society. doi:10.1093/zoolinnean/zlad167.
^Zofia Kielan-Jaworowska; Richard L. Cifelli; Zhe-Xi Luo (2004). "Chapter 7: Eutriconodontans". Mammals from the Age of Dinosaurs: origins, evolution, and structure. New York: Columbia University Press. pp. 216–248. ISBN0-231-11918-6.