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°30′S 44°30′W / 2.5°S 44.5°W / -2.5; -44.5
Approximate paleocoordinates9°24′S 19°18′W / 9.4°S 19.3°W / -9.4; -19.3
RegionMaranhão
CountryBrazil
ExtentSão Luís-Grajaú Basin
Type section
Named forAlcântara (city)
Named byRossetti & Truckenbrodt
Year defined1997
Alcântara Formation is located in Brazil
Alcântara Formation
Alcântara Formation (Brazil)

Fossil content

edit
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.

Dinosaurs

edit

Ornithischians

edit
Ornithischians of the Alcântara Formation
Genus Species Location Stratigraphic position Material Notes Image
Ornithopoda indet. Indeterminate Laje do Coringa, Cajual Island Footprints [2] Footprints interpreted as coming from both small and large ornithopods. Larger footprints have been tentatively assigned to hadrosaurs.

Sauropods

edit
Sauropods of the Alcântara Formation
Genus Species Location Stratigraphic position Material Notes Images
Itapeuasaurus[3] I. cajapioensis Itapeua beach A rebbachisaurine rebbachisaurid
cf. Limaysaurus[4] L. tessonei Laje do Coringa, Cajual Island Vertebrae A limaysaurine rebbachisaurid
cf. Malawisaurus?[5][6] M. sp. Laje do Coringa, Cajual Island Tooth A tooth similar to Malawisaurus
Sauropoda indet.[6] Indeterminate Laje do Coringa, Cajual Island Teeth May belong to a titanosaurian or a diplodocoid rebbachisaurid
Titanosauria indet.[6] Indeterminate Laje do Coringa, Cajual Island Vertebrae and an osteoderm A titanosaurian sauropod

Theropods

edit
Theropods of the Alcântara Formation
Genus Species Location Stratigraphic position Material Notes Images
Abelisauridae indet.[7] Indeterminate Laje do Coringa, Cajual Island Two shed tooth crowns A abelisaurid theropod
Carcharodontosauridae indet.[8] Indeterminate Laje do Coringa, Cajual Island Teeth A carcharodontosaurid theropod
Noasaurinae indet.[9] Indeterminate Laje do Coringa, Cajual Island Nine teeth A noasaurine noasaurid; closely related to Masiakasaurus knopfleri.
Oxalaia[10] O. quilombensis Laje do Coringa, Cajual Island Fused premaxillae; isolated and incomplete left maxilla (both heavily damaged from the National Museum of Brazil fire) A spinosaurin spinosaurine which may be synonymus with Spinosaurus itself.[11] However, this has been disputed.[12]

Sigilmassasaurus[6]

S. brevicollis

Laje do Coringa, Cajual Island Two caudal vertebrae

Referral to Sigilmassasaurus was based on similarity to presumed caudal vertebrae of the genus from the Kem Kem Group. However, the 2022 study noted that these specimens are indeterminate spinosaurids, most likely belonging to Oxalaia considering the geographical and geological context.[13]

Spinosaurini indet.[14] Indeterminate Laje do Coringa, Cajual Island Teeth A spinosaurin spinosaurine different from Oxalaia.
Unenlagiinae Indet.[15] Indeterminate Laje do Coringa, Cajual Island, São Luís-Grajaú Basin Teeth A unenlagiine dromaeosaurid

Pterosauria

edit
Pterosaurs of the Alcântara Formation
Genus Species Location Stratigraphic position Material Notes Images
Anhangueridae indet.[6] Indeterminate Laje do Coringa, Cajual Island Teeth A anhanguerid pterosaur
Ornithocheiroidea Indet.[6] Indeterminate Laje do Coringa, Cajual Island Tooth A ornithocheiroid pterosaur

Crocodylomorphs

edit
Crocodylomorphs of the Alcântara Formation
Genus Species Location Stratigraphic position Material Notes Images
Candidodon[6] C. itapecuruense Laje do Coringa, Cajual Island Teeth A candidodontid notosuchian
Coringasuchus[16] C. anisodontis Laje do Coringa, Cajual Island Partial right dentary A ziphosuchian notosuchian

Turtles

edit
Turtles of the Alcântara Formation
Genus Species Location Stratigraphic position Material Notes Images
Pelomedusoides indet.[6] Indeterminate Laje do Coringa, Cajual Island Incomplete carapace An side-necked turtle

Squamates

edit
Squamates of the Alcântara Formation
Genus Species Location Stratigraphic position Material Notes Images
Seismophis[17] S. septentrionalis Laje do Coringa, Cajual Island Vertebrae A snake

Mosasaurs

edit
Mosasaurs of the Alcântara Formation
Genus Species Location Stratigraphic position Material Notes Images
Carinodens[6] C. fraasi Laje do Coringa, Cajual Island Dental A globidensin mosasaurine
Mosasauridae Indet.[18] Indeterminate Laje do Coringa, Cajual Island An indeterminate mosasaurid

Plesiosaurs

edit
Plesiosaurs of the Alcântara Formation
Genus Species Location Stratigraphic position Material Notes Image
Brachaucheninae Indet.[6] Indeterminate Laje do Coringa, Cajual Island Teeth A brachauchenine thalassophonean

Fish

edit
Fishes of the Alcântara Formation
GenusSpeciesLocationStratigraphic positionMaterialNotesImages
Adrianaichthys[19] A. pankowski Laje do Coringa, Cajual Island Scales A lepisosteiform fish
Aegyptobatus[20] A. kuehnei Laje de Coringa, Cajual Island A distobatid hybodont
Arganodus[6] A. tiguidiensis Laje do Coringa, Cajual Island Dental plates A arganodontid lungfish
Atlanticopristis[21] A. equatorialis Falésia do Sismito and Laje do Coringa, Cajual Island Fourteen denticle specimens (two complete) A sclerorhynchoid
Bartschichthys[6] B. sp. Laje do Coringa, Cajual Island Spines A cladistian
Ceratodus[6] C. brasiliensis Laje do Coringa, Cajual Island Dental plates A ceratodontid lungfish
C. humei
Distobatus[22] D. nutiae Laje de Coringa, Cajual Island Teeth A distobatid hybodont
Equinoxiodus[6] E. alcantarensis[23] Laje do Coringa, Cajual Island One complete and eight incomplete tooth plates A neoceatodontid lungfish
E. schuitzei[24]
Hybodontidae Indet.[6] Indeterminate Laje de Coringa, Cajual Island Teeth & Cephalic spines A hybodontid hybodont
Hylaeobatis[6] H. sp. Laje do Coringa, Cajual Island Tooth A ptychodontid lamniform
Lepidotes[6] L. sp. Laje do Coringa, Cajual Island Mineralized scales A lepidotid fish.
Lepisosteidae Indet.[25] Indeterminate Laje do Coringa, Cajual Island Scales A gar
Lonchidiidae Indet.[6] Indeterminate Laje de Coringa, Cajual Island Teeth & Dorsal Spines A lonchidiid hybodont
Mawsonia[26] M. gigas Laje do Coringa, Cajual Island Palato-quadrate and post-parietal cranial material A mawsoniid coelacanth.
Myliobatis[6] M. dixoni Laje do Coringa, Cajual Island A myliobatid eagle ray
Obaichthys[6] O. africanus Laje do Coringa, Cajual Island Scales A obaichthyid lepisosteiform
Onchopristis cf. O. numida[27] Laje do Coringa, Cajual Island Rostral teeth A sclerorhynchoid
Pycnodontiformes indet.[6] Indeterminate Laje do Coringa, Cajual Island Dental plate and teeth
Stephanodus[6] S. sp. Laje do Coringa, Cajual Island Pharyngeal teeth A pycnodontid pycnodont
Tribodus[6] T. limae Laje do Coringa, Cajual Island Dorsal spines A hybodont shark

Plants

edit
Plants of the Alcântara Formation
Genus Species Location Stratigraphic position Material Notes Image
Araucariaceae Indet.[6] Indeterminate Laje do Coringa, Cajual Island Log A pine
Paradoxopteris[6] P. sanctiluigi Laje do Coringa, Cajual Island Stalk fragment A giant tree fern

References

edit
  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. de Souza Carvalho, Ismar; Lindoso, Rafael Matos (2024), Carvalho, Ismar de Souza; Leonardi, Giuseppe (eds.), "Equatorial Dinosaurs During the Opening of Atlantic Ocean: The São Luís Basin Footprints", Dinosaur Tracks of Mesozoic Basins in Brazil: Impact of Paleoenvironmental and Paleoclimatic Changes, Cham: Springer Nature Switzerland, pp. 233–262, doi:10.1007/978-3-031-56355-3_9, ISBN 978-3-031-56355-3, retrieved 2025-10-26{{citation}}: CS1 maint: work parameter with ISBN (link)
  3. 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. Bibcode:2019CrRes.10404191L. doi:10.1016/j.cretres.2019.104191. ISSN 0195-6671. S2CID 201321631.
  4. 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. Bibcode:2004RvBrP...7..275M. doi:10.4072/rbp.2004.2.22. hdl:10183/216922.
  5. 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.
  6. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 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. Bibcode:2014JSAES..53...50M. doi:10.1016/j.jsames.2014.04.002.
  7. Marcos A.F. Sales; Isabel A.P. de Oliveira; Cesar L. Schultz (2018). "The oldest abelisaurid record from Brazil and the palaeobiogeographic significance of mid-Cretaceous dinosaur assemblages from northern South America". Palaeogeography, Palaeoclimatology, Palaeoecology. 508: 107–115. Bibcode:2018PPP...508..107S. doi:10.1016/j.palaeo.2018.07.024. S2CID 133650699.
  8. 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).
  9. 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. Bibcode:2012CrRes..36..119L. doi:10.1016/j.cretres.2012.03.002.
  10. 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.
  11. Smyth, Robert S.H.; Ibrahim, Nizar; Martill, David M. (2020). "Sigilmassasaurus is Spinosaurus: A reappraisal of African spinosaurines". Cretaceous Research. 114 104520. Bibcode:2020CrRes.11404520S. doi:10.1016/j.cretres.2020.104520.
  12. Isasmendi, Erik; Navarro-Lorbés, Pablo; Sáez-Benito, Patxi; Viera, Luis I.; Torices, Angelica; Pereda-Suberbiola, Xabier (2023-06-03). "New contributions to the skull anatomy of spinosaurid theropods: Baryonychinae maxilla from the Early Cretaceous of Igea (La Rioja, Spain)". Historical Biology. 35 (6): 909–923. Bibcode:2023HBio...35..909I. doi:10.1080/08912963.2022.2069019. ISSN 0891-2963.
  13. Terras, R.; Carbonera, M.; Budke, G.; Leite, K.J.G. (2022). "Família Spinosauridae (Dinosauria: Theropoda): Taxonomia, Paleobiogeografia e Paleoecologia (Uma Revisão)". Paleontologia Em Destaque. 37 (77): 14–54. doi:10.4072/paleodest.2022.37.77.02.
  14. 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. Bibcode:2006RvBrP...9..333M. doi:10.4072/rbp.2006.3.08.
  15. Letizio LA, Bertini RJ, Medeiros MA (2022-07-16). "New evidence of putative Unenlagiinae (Deinonychosauria, Theropoda) in the São Luís-Grajaú Basin, Albian–Cenomanian, State of Maranhão, Brazil". Revista Brasileira de Paleontologia. 25 (2): 157–164. doi:10.4072/rbp.2022.2.05.
  16. 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.
  17. 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. hdl:11336/99860.
  18. Candeiro, Carlos Roberto; et al. (January 2025). "Late Cretaceous mosasaurids of northeastern Brazil: a summary of their record and a paleobiogeographical survey" (PDF). Andean Geology. 52 (1): 150–161 via SciELO.
  19. Ribeiro-Souza, E.; Alves, Y. M.; Schultz, C. L.; Medeiros, M. A. (2025). "Revaluation of the taxonomy and diversity of Lepisosteiformes from the Alcântara Formation (Cenomanian, Upper Cretaceous), Brazil". Cretaceous Research 106291. doi:10.1016/j.cretres.2025.106291.
  20. Neves, G. S.; Medeiros, M. A.; Dutheil, D. B.; Brito, P. M. (2024). "First record of Aegyptobatus (Hybodontiformes: Distobatidae) in the Cretaceous Alcântara formation (?Albian-Cenomanian) of Maranhão, Northeastern Brazil". Historical Biology: An International Journal of Paleobiology: 1–7. doi:10.1080/08912963.2024.2379031.
  21. 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. Bibcode:2008RvBrP..11..207P. doi:10.4072/rbp.2008.3.07.
  22. Neves, G. S.; Medeiros, M. A.; Cupello, C.; Leite Filho, D.; Brito, P. M. (2026). "Hybodontiform sharks from the Late Cretaceous Alcântara Formation, São Luís Basin, Northeast Brazil". Historical Biology: An International Journal of Paleobiology: 1–15. doi:10.1080/08912963.2025.2582776.
  23. 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. hdl:11449/25070. PMID 22146953.
  24. Eliane Pinheiro De Sousa; Manuel Alfredo Medeiros; Carlos Eduardo Vieira Toledo; Reinaldo J. Bertini; Agostinha Araújo Pereira; Rafael Matos Lindoso (2015). "A new species of Equinoxiodus (Dipnoi: ?Neoceratodontidae) from the Late Cretaceous of Brazil". Zootaxa. 3905 (3): 397–406. doi:10.11646/zootaxa.3905.3.5. PMID 25661218.
  25. Brito, P. M.; Pinheiro, A. E. P.; Ribeiro, T. B.; Medeiros, M. A. (2024). "Lepisosteidae remains (Holostei: Ginglymodi) from the Middle Cretaceous Alcântara Formation, Northeastern Brazil". Journal of South American Earth Sciences. 152. 105289. doi:10.1016/j.jsames.2024.105289.
  26. 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.
  27. Pereira, A.A.; Medeiros, M.A. (2003). "Novas ocorrências de peixes no Eocenomaniano do Maranhão". Congresso Brasileiro de Paleontologia. Vol. 18. Boletim de Resumos, UNB Brasília. pp. 221–222.