Paleoparasitological study of avian trace fossils from the Tremembé Formation (Oligocene of the Taubaté Basin), São Paulo, Brazil

Abstract

Coprolites are promising tools for the understanding of paleoecological and paleoenvironmental aspects. Through its chemical composition and analysis of micro- and macrostructures, it is possible to obtain information about the diet of ancient animals and insights into the climate and vegetation of paleoenvironments. Paleoparasitological analysis of these trace fossils help to understand the parasite-host relationship and how parasitic infections were processed in the past. The present study aims to identify helminths in coprolites of the Tremembé Formation (Oligocene of the Taubaté Basin, São Paulo). Furthermore, we included the descriptive association of the paleoparasitological data with the paleoenvironmental information present in the literature for this geological formation. Eggs were identified through linear morphometry and morphology. The paleoparasitological analysis revealed the presence of Nematode eggs of Ascaridina, Spirurina, and Trichocephalida, with a prevalence of 5% for each group. The complex life cycle of some nematodes would be made possible by the wide faunal diversity of birds, fish, and arthropods that inhabited the Tremembé paleolake. The low prevalence of helminths in the samples may be related to taphonomic processes. This study represents the first paleoparasitological analysis of avian coprolites from the Tremembé Formation. In addition, the finding of these helminth records creates new perspectives for the studies of this geological unit through the epidemiological point of view associated with the local paleofauna and also provides new subsidies for the further development of evolutionary and biogeographic helminth studies.