THE FOSSIL RECORD OF PARASITISM IS CRITICAL FOR CONSERVATION: ASSESSING FIDELITY IN THE CRUSTACEAN FOSSIL RECORD

The ecology of parasitism in deep time remains a relatively underdeveloped field of study in comparison to the larger body of work exploring the importance of predation in the fossil record. Studies have demonstrated the tremendous diversity of extant parasites and their integral part in shaping and stabilizing ecosystems, highlighting the need to better resolve and analyze parasite paleobiological data. One likely bias impacting the fossil record of parasitism is preservation. Understanding the taphonomy of parasitism in the fossil record is critical to disentangling ecological signals from bias, and therefore understanding modern and future parasite-host ecology in the context of fossil data. Resolving the biases affecting the fossil record of parasitism, as well as the unevenness of these biases across taxa, time, and space, will allow conservation paleobiological study of parasites in deep time, such as the creation of pre-human baselines for parasite prevalence and range, and modelling future changes to parasite ecology using data from past intervals of climatic change, such as the Paleocene-Eocene Thermal Maximum. Here, we present two case studies for understanding the preservation of healthy and parasitized crustaceans, and highlight the importance of the parasite fossil record for conservation paleobiology. First, we use physical simulations to analyze the impact of a parasite-induced fossil swelling on host preservation. We found measurable differences in peak stress in parasitized branchial chambers, indicating that the shape of this pathology compromises the structure, which in turn likely hinders preservation. Second, we use experimental tumbling to observe, compare, and contrast taphonomic characteristics between blue crabs infested with a rhizocephalan parasite, and uninfested blue crabs from the Gulf of Mexico. These studies are early but critical steps toward a better quantitative understanding of the fossil record of parasitism, and highlight the need disentangle bias from ecological signal, to allow for the informed use of parasite paleobiological data to inform current and future conservation. Studying the taphonomy of parasitism is critical to understanding the fossil record of parasitism, which is in turn critical for modelling future change in parasite ecology and informing conservation efforts.