Development and application of a new paleoclimatological proxy with examples from the Holocene of Kentucky and Miocene

O'KEEFE, JENNIFER M.K.; ROMERO, INGRID C.; NUÑEZ OTAÑO, NOELIA B.; POUND, MATTHEW J.; ALDEN, MARGARET; CALDWELL, ABIGAYLE; FAIRCHILD JOLENE C.; GARDNER, KRISTINA; HORSFALL, TAYLOR; JONES, SAVANNAH

Morehead, KY

Jornada; Kentucky Academy of Science Annual Meeting 2022; 2022

Morehead State University

Palynomorphs, including pollen, plant spores, and dinoflagellates are widely used paleoclimatological proxies because they provide a regional-scale signal. Within the spectrum of organismal remains classified as “palynomorphs” in the fossil record, fungi provide a unique opportunity to elucidate a local, rather than regional signal. Historically, paleoclimatological interpretations using fossil fungi have been hampered by datasets which relied on fossil names, many of which were derived from Sarccado spore morphologies and had no relation to extant taxa. Beginning with the North-South America comparing Climate change across Hemispheres (NSACH) project and continuing with the Fungi in a Warmer World (FiaWW) project, our collaborative team has developed an identification method based on the system used by mycologists for morphological comparisons to equate defined fossil taxa with their nearest living relatives and to identify previously unidentified fossil taxa as members of extant fungal clades. This permits the delineation of ecological requirements and paleobiogeographic distribution patterns for fungal assemblages and functional guilds in the fossil record, which can then be used to describe both paleoecological conditions and paleoclimates present at the time of deposition using the nearest living relative method. Here we present an overview of results from the Holocene of Kentucky and Miocene across the United States that demonstrate the utility of fossil fungi as reliable paleoclimate proxies.