Navegando por Autor "COSTA, Sue Anne Regina Ferreira da"

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A comunidade de tubarões (Chondrichthyes : selachii : Galea) da formação pirabas, Neógeno da Amazônia Oriental
(Universidade Federal do Pará, 2005-03-10) COSTA, Sue Anne Regina Ferreira da; RICHTER, Martha; http://lattes.cnpq.br/9381228195500524; TOLEDO, Peter Mann de; http://lattes.cnpq.br/3990234183124986
The shark community (Selachii:Galea) from the Pirabas Formation in one of the most representative of the Neogene in South America due to its high diversity of taxa and range of ecological components. The presence of eight known genera enabled to establish hypothesis about the trophic chain of the vertebrate palaeocommunity, as well as to corroborate previous reconstructions about the paleoenvironmental parameters of this geologic unit. This study dealt with the taxonomic revision of the shark community on both generic and species leveis, allowing the following composition: Carcharhinus spl, Carcharhinus sp2, Carcharhinus sp3, Carcharhinus priscus, Sphyrna magna, Hemipristis serra, Carcharodon megalodon, Isurus sp, Ginglymostoma serra, Ginglymostoma obliquum. The analyses of newly collected specimens and microscopic material allowed a considerable expansion of identified individuals up to 231 teeth. This work is a contribution to refine the knowledge about the regional patterns of shark paleobiogeography.
Acesso aberto (Open Access)
Ictiólitos da Formação Pirabas, mioceno do Pará, Brasil, e suas implicações paleoecológicas
(Universidade Federal do Pará, 2011-06-01) COSTA, Sue Anne Regina Ferreira da; RICHTER, Martha; http://lattes.cnpq.br/9381228195500524; ROSSETTI, Dilce de Fátima; http://lattes.cnpq.br/0307721738107549
The Pirabas Formation (Oligo-miocine), which is represented by carbonates deposits through the Brazilian Coastal Area between the States of Pará and Piauí, is recognized for its fossil richness. Among the many fossils paleoichthyofauna stands out for its abundance in outcrops, but the absence of stratigraphic and facies control of these fossil restricted their potential use in paleoenvironmental interpretations. The joint use of the technique of wet sieving for the recovery of ichthyoliths and microfacies and facies analysis of sediments taken from Pirabas Formation deposits, which were exposed in the B17 mine (Capanema-PA), allowed for the first time the use of vertebrate fossil for the elaboration of an interdisciplinary paleoenvironmental reconstruction model. The 3594 recovered ichthyoliths, along with the 5 facies associations and the 4 carbonate microfacies, led to the conclusion that these deposits of Pirabas Formation were formed in marine-marginal depositional system, with different environments genetically associated as shore face (surf zone), beach, lagoon, tidal channel and tidal delta, which would be part of an estuarine system with the influence of wave, marked by four different depositional cycles related to possible transgressiveregressive episodes. The estuarine environment was confirmed by the assembly of ichthyoliths, observing that this assembly is formed by both freshwater specimens, represented by the Characidae family, an unheard occurrence for the unit until then, as for marine specimens, for example, the sharks. Several dental types, possibly attributed to representatives of brackish waters, such as the genera Dasyatis and Sarpa, both equally registered for the first time, also strengthens the proposed environment. The distribution of the ichthyological community evidences palaeoenvironmental control, having registered their highest abundance in deposits of tidal channel. However, the influence of relative sea level resulted in the development of transgressive-regressive depositional cycles, which also exerted strong control on the stratigraphic distribution of the B17 Mine registered ichthyoliths, reinforcing the importance of interdisciplinary studies in refining palaeoecological reconstruction of this unit.