Paleontological data obtained in recent years reinforce the hypothesis that Aptian marine sedimentation in the sedimentary basins of the Brazilian continental margin -except the Pelotas basin, the southernmost Brazilian basin -took place under the domain of waters coming from the north through the Tethys Sea (Central Atlantic). Tethyan waters could reach the basins of the Brazilian continental margin via the seaway then existing in the present-day region of northeastern Brazil. Here there are

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... cords in several basins, notably in the São Luís (Codó Formation), Parnaíba (Codó Formation), Araripe (Santana Formation), Tucano (Marizal Formation), Sergipe (Riachuelo Formation) and Camamu (Algodões Formation) basins. Despite irrefutable marine evidence -e.g., dinoflagellates, echinoids, foraminifera, molluscs and fishes, conspicuously present in the Araripe Basin -there are very few paleogeographic reconstructions that include the seaway which is totally ignored in the international literature. The skepticism is even greater in relation to the Tethyan affinity although the evidence has been well documented by molluscs and dinoflagellates, together with ammonoids in the Sergipe Basin. That skepticism may be due to the fact that, in tectonic and geodynamic terms, the opening of the South Atlantic indeed proceeded from south to north, at least in the part that extends from Argentina to the northeastern Brazilian state of Paraíba.