The Importance of Neoichnology to the Field of Micropaleontology – Roger Kaesler's Final Research Experiment

Roger Kaesler was a leader and visionary in the field of paleontology. He helped pioneer the use of multivariate statistical methods and quantitative techniques in macroevolution and heterochrony studies, especially in the field of micropaleontology. He also was a fervent believer in the application of paleontology to deciphering paleoenvironments, building biostratigraphic frameworks, reconstructing paleoecologic communities, and interpreting paleoclimate. Late in his life, Roger saw the need for more neoichnological experiments to understand better organismal media interactions, their behaviors, and preservation potential into the geological record, especially with microorganisms.

Using the nektobenthic freshwater ostracode Heterocypris incongruens (Ramdohr, 1808), two separate neoichnological experiments were conducted. First, a series of experiments were conducted in various grain sizes and water depths to determine the different types, morphologies, and behaviors of freshwater ostracodes in controlled microcosms. Six distinct traces were observed, including four locomotion, one resting, and one asymmetrical u-shaped burrow. Depth of the ostracodes traces ranged in from approximately 2 mm to small locomotion scratches at the sediment surface. The second series of neoichnological experiments looked at the potential for ostracode escape traces during catastrophic burial events. Preliminary data confirms that ostracodes are able to dig themselves out after being buried by 5 mm of ash. The ostracodes produce a vertical escape trace. On the sediment surface, the escape traces are the width of the ostracodes and leave a surface depression. The preservation potential for all freshwater ostracode traces is poor. Wave action will quickly destroy these traces, but preservation potential increases if the traces are quickly buried or subaerially exposed after formation. The importance of neoichnological experiments with microorganisms allows us to identify these traces in the fossil record and assist with paleoenvironmental reconstructions and rates of sedimentation.