TAPHONOMIC ANALYSIS IN SHELLS OF DIFFERENT ISOTOPIC MARINE STAGES: IMPLICATIONS FOR CONSERVATION PALEOBIOLOGY

Preservation potential is a key aspect in research related to Conservation Paleobiology, as it influences the integrity and quality of the fossil record used to reconstruct paleoenvironments. Taphonomic analyses generate information about the processes of destruction and alteration of biological remains, as well as about the intensity of the processes, which can vary according to environmental conditions, allowing us to understand how the potential for preservation affects the representativeness of the communities studied. In this sense, the objective of this work is to identify surface taphonomic alterations (e.g., dissolution and abrasion), degree of fragmentation and bioerosion in 60 shells of bivalve mollusks recovered from sediments of different marine isotopic stages (MIS), in the southern portion of the Coastal Plain of Rio Grande do Sul. In this work, 40 valves from surveys carried out in Pleistocene Barrier III deposits were analyzed. The shells of the HM29A07 sounding span ages between 178-336 ka, corresponding to MIS 7, 8 and 10. The ages of the shells of the G10A08 sounding correspond to the MIS 5a or 5c, 5e, 6, 7 and 8 (87-248 ka) substages. Another 20 valves were obtained by means of SPT probes made in Barrier IV substrate of Holocene age, and have ages corresponding to the MIS 3 stage (~41 ka). The shells from holes HM29A07 and G10A08 showed an intense degree of surface alteration, with a frequency of 70%, reaching up to 90% of the surface of the shells. They also concentrate higher values of bioerosion, with traces of Entobia isp., when compared to the shells of SPTs