HELICOPRION TOOTH WHORLS AS PALEOTHERMOMETRY PROXIES FOR THE PERMIAN PHOSPHORIA SEA

Despite being one of the largest and most distinctive predators of the Permian Phosphoria Sea, little is known about Helicoprion’s life history, environments, or feeding habits. Unlike other cartilaginous fish, Helicoprion retained its teeth within a continuous spiral on the lower jaw and therefore recorded environmental information within this unique structure. In such a continuous, alteration-resistant geochemical record, serial sampling can reveal patterns or changes in past ecosystems, such as water temperature, habitat, and seasonality. Prior investigation has revealed that analysis of Helicoprion teeth returns paleotemperature estimates in agreement with those obtained from other contemporaneous fossils. Here we present new oxygen isotope values sampled from 37 teeth of a whorl in the context of its phosphatic sedimentary matrix. This is the first attempt to identify long-term environmental variation over the lifespan of this unusual Permian predator.