NEW INSIGHTS INTO PALEOZOIC AMMONOID MACROEVOLUTION AND PALEOECOLOGY FROM WESTERMANN MORPHOSPACE

Ammonoid disparity is often conveyed using coiling parameters, such as the whorl expansion rate, umbilical width, and thickness ratio. While more readily interpretable than principle components, these values can still be somewhat abstract, and the precise significance of their trends can be difficult to understand. Westermann Morphospace converts these ratios into ecologically meaningful parameters, which can be utilized to infer a planktic, nektic, or demersal ecology. We measured 650 Paleozoic ammonoid species from the Treatise, Ammoneae Devonicae, and museum specimens. Trajectories within Westermann Morphospace are compared to standardized Paleozoic ammonoid diversity, and the ecological impacts of mass extinctions on the Paleozoic history of ammonoids are discussed.