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| faunal components of the Marfim Formation (Valanginian–Hauterivian), the Recôncavo Basin during Lower Cretaceous Tietasaura derbyiana Bandeira, Navarro, Pêgas, Brilhante, Brum, de Souza, da Silva & Gallo, 2024 |
ABSTRACT
Supposed dinosaur remains were collected between 1859 and 1906 in the Lower Cretaceous Recôncavo Basin (Northeast Brazil). Since these materials remained undescribed, and most were considered lost. Recently, some of these historical specimens were rediscovered in the Natural History Museum of London, providing an opportunity to revisit them after 160 years. The specimens come from five different sites, corresponding to the Massacará (Berriasian-Barremian) and Ilhas (Valanginian-Barremian) groups. Identified bones comprise mainly isolated vertebral centra from ornithopods, sauropods, and theropods. Appendicular remains include a theropod pedal phalanx, humerus, and distal half of a left femur with elasmarian affinities. Despite their fragmentary nature, these specimens represent the earliest dinosaur bones discovered in South America, enhancing our understanding of the Cretaceous dinosaur faunas in Northeast Brazil. The dinosaur assemblage in the Recôncavo Basin resembles coeval units in Northeast Brazil, such as the Rio do Peixe Basin, where ornithopods coexist with sauropods and theropods. This study confirms the presence of ornithischian dinosaurs in Brazil based on osteological evidence, expanding their biogeographic and temporal range before the continental rifting between South America and Africa. Additionally, these findings reinforce the fossiliferous potential of Cretaceous deposits in Bahia State, which have been underexplored since their initial discoveries.
KEYWORDS: Recôncavo Basin, Massacará Group, Ilhas Group, Ornithischia, Sauropoda, Theropoda
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| Paleontographical reconstruction of the hypothetical paleoenvironment of the Recôncavo Basin during Lower Cretaceous: A, faunal components of the Marfim Formation (Valanginian–Hauterivian); B, faunal components of the Pojuca Formation (Hauterivian–Barremian). The Salvador Formation is partially synchronous with both units, sharing coeval components. Artwork by Matheus Gadelha. |
Dinosauria Owen Citation1842
Ornithischia Seeley Citation1888
Genasauria Sereno Citation1986
Neornithischia Cooper Citation1985
Cerapoda Sereno Citation1986
Ornithopoda Marsh Citation1881
Elasmaria Calvo et al. Citation2007
Tietasaura gen. nov.
Etymology: The generic epithet is a combination of Tieta (nickname for Antonieta in Portuguese) and -saura (σαύρα), the genitive form of -saurus and meaning lizard in ancient Greek. The name Tieta honours the main character from the homonymous novel ‘Tieta do Agreste’ by the famous author Jorge Amado, who was born in Bahia and lived in Salvador City. The name Antonieta further means ‘priceless’, alluding to the value of Tietasaura derbyiana sp. nov. as the first nominal ornithischian species from Brazil.
Tietasaura derbyiana sp. nov.
Etymology: The specific epithet is an eponym honouring Orville A. Derby (1851–1915), founder and the first director from Brazilian Mineralogical and Geological Commission (Serviço Geológico e Mineralógico do Brasil, nowadays SGB), being also the former director of the National Museum of Rio de Janeiro (MN) and one of the pioneers of palaeontology in the Recôncavo Basin. Despite all tragedies in his life and the blatant lack of governmental support, Derby valiantly fought for the scientific progress of the Brazilian geosciences.
Holotype: NHM-PV R.3424, represented by a distal half of a small left femur.
Diagnosis: Small sized elasmarian ornithopod exhibiting an unique combination of character states on the femur (putative autapomorphies marked with an asterisk): presence of a marked anterior linea muscularis followed by several longitudinal striae converging distally towards the intercondylar extensor groove; broad but shallow intercondylar extensor groove; stout supracondylar ridges that extends medially; fibular supracondylar ridge sinuous and bearing a lateral fossa*; hemispherical distal femoral condyles in the posterior view, being the tibial condyle twice as large as fibular condyle; distinct prominent crest in the median margin of the tibial condyle*; fibular condyle with straight lateral margin and continuous in the distal view, lacking an indentation formed by a condyloid (rectangular) process; presence of an offset condylid, medial to the fibular condyle; broad and deep intercondylar flexor fossa, subtriangular in shape and much extending into the diaphysis.
Type locality and horizon: The holotype of Tietasaura derbyiana was recovered at a beach near the Plataforma Station (Locality 3), Salvador City, Bahia State. The shale facies outcropping in this locality are associated with the Valanginian – Hauterivian Marfim Formation (Ilhas Group, Recôncavo Basin).
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Kamila L. N. Bandeira, Bruno A. Navarro, Rodrigo V. Pêgas, Natan S. Brilhante, Arthur S. Brum, Lucy G. de Souza, Rafael C. da Silva and Valéria Gallo. 2024. A Reassessment of the historical Fossil Findings from Bahia State (Northeast Brazil) reveals A diversified Dinosaur Fauna in the Lower Cretaceous of South America. Historical Biology: An International Journal of Paleobiology. DOI: 10.1080/08912963.2024.2318406 Researchgate.net/publication/379778273_fossil_findings_from_Bahia_NE_Brazil
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