The Invertebrates of The Romualdo Formation, Araripe Basin: Analysis of Paleoecological and Paleogeographical Data

Fossil invertebrates are good paleoenvironmental indicators due to their sensitivity to abiotic conditions, which contributes to the understanding of the Aptian-Albian of the Araripe Basin. However, much of the paleoecological and paleobiogeographical information on these organisms is scarce in the literature. The aim of this paper is to compile relevant data on the macroinvertebrates of the Romualdo Formation and to analyze and point out gaps in knowledge. To achieve this, extensive bibliographical research was carried out, using scientific publications based on the families of Spinicaudata, echinoids, gastropods, bivalves, shrimps and crabs of the Romualdo Formation and their distribution in Brazil and globally throughout the Aptian-Albian, using specialized online databases. Paleoecological and paleogeographical data were compiled for 46 invertebrate taxa, highlighting those with better studied routes of origin. Thus, it was possible to highlight the lack of data regarding the way of life of certain mollusc families and systematic problems regarding the identification of the families of several species of shrimp. Finally, the predominance of taxa from marine (34), brackish (7) and lacustrine (5) waters was shown. Of these, 18 taxa have a typical tethyan distribution and another 12 also present occurrences in the Austral, Boreal or both domains. The only typical freshwater group was Spinicaudata, marking environments with little or no marine influence and with rare occurrences during the Aptian-Albian.