Alcântara Formation

The Alcântara Formation is a geological formation in northeastern Brazil whose strata date back to the Cenomanian of the Late Cretaceous.[1]

Alcântara Formation
Stratigraphic range: Cenomanian
TypeGeological formation
Unit ofItapecuru Group
UnderliesCujupe Formation
OverliesUndifferentiated unit
Thickness30–35 m (98–115 ft)
Lithology
PrimarySandstone
OtherClaystone, conglomerate
Location
Coordinates2.5°S 44.5°W / -2.5; -44.5
Approximate paleocoordinates9.4°S 19.3°W / -9.4; -19.3
Region Maranhão
Country Brazil
ExtentSão Luís-Grajaú Basin
Type section
Named forAlcântara (city)
Named byRossetti & Truckenbrodt
Year defined1997
Alcântara Formation (Brazil)

Fossil content

Dinosaurs
Dinosaurs
Genus Species Location Stratigraphic position Material Notes Images
Carcharodontosauridae indet.[2] Indeterminate Laje do Coringa, Cajual Island Early Cenomanian Teeth
Dromaeosauridae indet.[3] Indeterminate Laje do Coringa, Cajual Island Early Cenomanian Teeth Possible member of Velociraptorinae
Itapeuasaurus[4] I. cajapioensis Itapeua beach Early Cenomanian A rebbachisaurid
cf. Limaysaurus[5] L. tessonei Laje do Coringa, Cajual Island Early Cenomanian Vertebrae
Malawisaurus[6] M. sp. Laje do Coringa, Cajual Island Early Cenomanian Tooth
Noasauridae indet. [7] Indeterminate Laje do Coringa, Cajual Island Early Cenomanian Nine teeth Teeth belong to an animal closely related to Masiakasaurus knopfleri.
Oxalaia[8] O. quilombensis Laje do Coringa, Cajual Island Early Cenomanian Fused premaxillae; isolated and incomplete left maxilla A spinosaurid
Sauropoda indet.[3] Indeterminate Laje do Coringa, Cajual Island Early Cenomanian Teeth May belong to a titanosaurid or a diplodocoid rebbachisaurid

Sigilmassasaurus[3]

S. brevicollis

 Laje do Coringa, Cajual Island Early Cenomanian Two caudal vertebrae

Referral to Sigilmassasaurus was based on similarity to presumed caudal vertebrae of the genus from the Kem Kem Group. However, these caudal vertebrae have since been separated from the genus, meaning that it is currently impossible to refer any caudal vertebrae to it.
Spinosauridae indet.[9] Indeterminate Laje do Coringa, Cajual Island Early Cenomanian Teeth A spinosaurid different from Oxalaia.
Theropoda indet.[3] Indeterminate Laje do Coringa, Cajual Island Early Cenomanian Claw
Titanosauria indet.[3] Indeterminate Laje do Coringa, Cajual Island Early Cenomaninan Vertebrae
Titanosauria indet.[3] Indeterminate Laje do Coringa, Cajual Island Early Cenomaninan Osteoderm

Pterosauria
Pterosaurs
Genus Species Location Stratigraphic position Material Notes Images
Anhangueridae indet.[3] Indeterminate Laje do Coringa, Cajual Island Early Cenomanina Teeth

Crocodylomorphs
Crocodylomorphs
Genus Species Location Stratigraphic position Material Notes Images
Crocodylomorpha indet.[3] Indeterminate Laje do Coringa, Cajual Island Early Cenomanian Teeth and osteoderms
Coringasuchus[10] C. anisodontis Laje do Coringa, Cajual Island Early Cenomanian Partial right lower jaw (dentary) Possibly a notosuchian

Turtles
Crocodylomorphs
Genus Species Location Stratigraphic position Material Notes Images
Pelomedusoides indet.[3] Indeterminate Laje do Coringa, Cajual Island Early Cenomanian Incomplete carapace

Squamates
Snakes
Genus Species Location Stratigraphic position Material Notes Images
Seismophis[11] S. septentrionalis Laje do Coringa, Cajual Island Early Cenomanian Vertebrae A snake

Fish
Fishes
GenusSpeciesLocationStratigraphic positionMaterialNotesImages
Arganodus[3] A. tiguidiensis Laje do Coringa, Cajual Island Early Cenomanian Dental plates A ceratodontid lungfish
Atlanticopristis[12] A. equatorialis Falésia do Sismito and Laje do Coringa, Cajual Island Early Cenomanian Fourteen denticle specimens (two complete) A sclerorhynchid
Bartschichthys[3] B. sp. Laje do Coringa, Cajual Island Early Cenomanian Spines
Ceratodus[3] C. brasiliensis
C. humei		 Laje do Coringa, Cajual Island Early Cenomanian Dental plates A ceratodontid lungfish
Equinoxiodus[13] E. alcantarensis
E. sp.[3]		 Laje do Coringa, Cajual Island Early Cenomanian One complete and eight incomplete tooth plates A dipnoiform
Lepidotes[3] Lepidotes sp. Laje do Coringa, Cajual Island Early Cenomanian Mineralized scales
Mawsonia[14] M. gigas Laje do Coringa, Cajual Island Early Cenomanian Palato-quadrate and post-parietal cranial material A coelacanthiform
Myliobatis[3] M. sp. Laje do Coringa, Cajual Island Early Cenomanian
Onchopristis[3] O. cf. numidus Laje do Coringa, Cajual Island Early Cenomanian Rostral teeth A sclerorhynchoid.
Pycnodontiformes indet.[3] Indeterminate Laje do Coringa, Cajual Island Early Cenomanian Dental plate and teeth
Stephanodus[3] S. sp. Laje do Coringa, Cajual Island Early Cenomanian Pharyngeal teeth
Tribodus[3] T. cf. limae Laje do Coringa, Cajual Island Early Cenomanian Dorsal spines A hybodont
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.

References
  1. Rossetti, D.F.; Truckenbrodt, W. (1997). "Revisão estratigráfica para os depósitos do Albiano-Terciário Inferior (?) na Bacia de São Luís (MA), Norte do Brasil". Boletim do Museu Paraense Emílio Goeldi. 9: 29–41.
  2. Candeiro, C.R.A.; Martinelli, Agustin G. (2005). "Abelisauroidea and Carcharodontosauridae (Theropoda, Dinosauria) in the Cretaceous of South America. Paleogeographical and geocronological implications". Sociedade & Natureza. 17 (33).
  3. Medeiros, Manuel Alfredo; Lindoso, Rafael Motos; Mendes, Ighor Dienes; Carvalho, Ismar de Souza (2014). "The Cretaceous (Cenomanian) continental record of the Laje do Coringa flagstone (Alcântara Formation), northeastern South America". Journal of South American Earth Sciences. 53: 50–58. doi:10.1016/j.jsames.2014.04.002.
  4. Lindoso, Rafael Matos; Medeiros, Manuel Alfredo Araújo; Carvalho, Ismar de Souza; Pereira, Agostinha Araújo; Mendes, Ighor Dienes; Iori, Fabiano Vidoi; Sousa, Eliane Pinheiro; Arcanjo, Silvia Helena Souza; Silva, Taciane Costa Madeira (July 2019). "A new rebbachisaurid (Sauropoda: Diplodocoidea) from the middle Cretaceous of northern Brazil". Cretaceous Research. 104: 104191. doi:10.1016/j.cretres.2019.104191. ISSN 0195-6671.
  5. Medeiros, Manuel Alfredo; Schultz, Cesar Leandro (2004). "Rayososaurus (Sauropoda, Diplodocoidea) no meso-Cretáceo do Norte-Nordeste Brasileiro". Revista Brasileira de Paleontologia. 7 (2): 275–279. doi:10.4072/rbp.2004.2.22.
  6. Freire, Pedro Carvalho; Medeiros, Manuel Alfredo; Lindoso, Rafael Matos (2007). "Sauropod teeth diversity in the Laje do Coringa fossiliferous site, Eocenomanian of Northeastern Brazil". Paleontologia: Cenários de Vida: 523–532.
  7. Lindoso, Rafael Matos; Medeiros, Manuel Alfredo; Carvalho, Ismar de Souza; Marinho, Thiago da Silva (August 2012). "Masiakasaurus-like theropod teeth from the Alcântara Formation, São Luís Basin (Cenomanian), northeastern Brazil". Cretaceous Research. 36: 119–124. doi:10.1016/j.cretres.2012.03.002.
  8. Kellner, Alexander W.A.; Azevedeo, Sergio A.K.; Machado, Elaine B.; Carvalho, Luciana B.; Henriques, Deise D.R. (2012). "A new dinosaur (Theropoda, Spinosauridae) from the Cretaceous (Cenomanian) Alcântara Formation, Cajual Island, Brazil" (PDF). Anais da Academia Brasileira de Ciências. 83 (1): 99–108. doi:10.1590/S0001-37652011000100006. ISSN 0001-3765. PMID 21437377.
  9. Medeiros, Manuel Alfredo (2006). "Large theropod teeth from the Eocenomanian of northeastern Brazil and the occurrence of Spinosauridae". Revista Brasileira de Paleontologia. 9 (3): 333–338. doi:10.4072/rbp.2006.3.08.
  10. Kellner, A.W.A.; Pinheiro, A.E.P.; Azevedo, S.A.K.; Henriques, D.D.R.; de Carvalho, L.B.; Oliveira, G.R. (2009). "A new crocodyliform from the Alcântara Formation (Cenomanian), Cajual Island, Brazil". Zootaxa. 2030: 49–58. doi:10.11646/zootaxa.2030.1.4. S2CID 88042701.
  11. Hsiou, A. S.; Albino, A. M.; Medeiros, M. A.; Santos, R. A. B. (2013). "The oldest Brazilian snakes from the early Late Cretaceous (Cenomanian)". Acta Palaeontologica Polonica. 59 (3): 635–642. doi:10.4202/app.2012.0091.
  12. Pereira, A.A.; Medeiros, M.A. (2008). "A new sclerorhynchiform (Elasmobranchii) from the middle Cretaceous of Brazil". Revista Brasileira de Paleontologia. 11 (3): 207–212. doi:10.4072/rbp.2008.3.07.
  13. Toledo, C.E.; Sousa, E.P.; Medeiros, M.A.; Bertini, R.J. (2011). "A new genus of dipnoiformes from the Cretaceous of Brazil". Anais da Academia Brasileira de Ciências. 83 (4): 1181–1192. doi:10.1590/s0001-37652011000400006. PMID 22146953.
  14. Medeiros, M.A., Carvalho, M.S.S., Silva, M.A.M., Pereira, A.A., Araujo, M.N., Ferreira, N.N., Vilas Bôas, I., 2011. O senhor dos rios: Mawsonia gigas (Mawsoniidae) do Cenomaniano do Maranhão, Brasil. In: Carvalho, I.S., Srivastava, N.K., Strohschoen, J.O., Lana, C.C. (Eds.), Paleontologia: Cenários de Vida, Vol. 4. Interciência, Rio de Janeiro, pp. 575-583.
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