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Crato Wetlands - A revised paleoenvironment

Reconstruction of the new interpretation for the paleoenvironment of the Crato Formation, Lower Cretaceous of the Brazilian Northeast, according to the recently published research by Alexandre Ribeiro and colleagues.

The team analyzed the literature about the fossils and previous attempts to interpret this environment and investigated new fossils from the Konservat-Lagerstätte (deposits with exceptional preservation of organisms and / or their features, such as soft tissue) Crato, their stratigraphic and ecological distribution according to the lives of these organisms and their modern parallels in extant relatives. Unlike the many previous hypotheses for the Crato paleoenvironment, for example a shallow and eutrophic lake, a mangrove or a deep lacustrine system, the study by Ribeiro and colleagues points to Crato as a shallow, lacustrine wetland with high seasonal variation in a semi-arid climate, something without many modern analogues, the most notable being Lake Chad, in Africa.

The image illustrates the 4 ecotones inferred for the paleoenvironment (xeric, mesophytic, helophytic and aquatic) during 3 seasonal conditions that dictate the water level. The location of the organisms reflects their distribution in the habitats (except for the represented tetrapods, which are not necessarily limited to the ecotone or season where they appear in the image), prospering or perishing according to the flood and the drought. A big wildfire also appears in the scene, a phenomenon that directly impacts the sediment due to the burning of organic matter.

With great pleasure I made this illustration with the invitation and supervision of Alexandre for the article!

The paper's citation:
Ribeiro, A. C., Ribeiro, G. C., Varejão, F. G., Battirola, L. D., Pessoa, E. M., Simões, M. G., Warren, L. V., Riccomini, C., & Poyato-Ariza, F. J. (2021). Towards an actualistic view of the Crato Konservat-Lagerstätte paleoenvironment: A new hypothesis as an Early Cretaceous (Aptian) equatorial and semi-arid wetland. Earth-Science Reviews, 216, 103573.