IT'S COMPLICATED: HOW QUANTITATIVE METHODS REVEAL THE COMPLEX DYNAMISM OF FUNCTIONAL LANDSCAPES AND WHY THAT'S A GOOD THING

Advances in 3D modeling and simulation offer paleontologists powerful tools to scrutinize functional morphology and animal-ecosystem interactions. Adopting these methods allows us to closely emulate and extend methods of prior experimental studies, but we also generate incredible amounts of data. Ironically, a wealth of data can cloud our once-simple interpretations of functional morphology, forcing us to refine metrics of performance and potential interactions.

Here we investigate this phenomenon by considering functional morphology of ammonoid cephalopods. We used suites of theoretical morphologies to transect Westermann Morphospace, an empirical morphospace commonly used to relate planispiral ammonoid morphology to their hydrodynamic capabilities. Ammonoid ecological capabilities are often evaluated via two straightforward performance metrics: drag force (in the form of drag coefficient); and the maximum speed the shell could attain. While useful, drag and maximum speed do not fully capture the physics of the system, nor do they clarify realistic costs and benefits between locomotion styles. The amount and breadth of data we were able to capture from our simulations combined with the utility of 3D models allowed us to build a numerical model that can incorporate additional physics into our model and examine the hydrodynamic consequences of these morphological differences under more realistic scenarios. Our results reveal a much more dynamic performance landscape for these morphologies than had been previously asserted. This provides valuable insight into morphological studies reaching far beyond ammonites, and shows that the discipline as a whole is capable, and indeed should, boldly consider and test more sophisticated functional hypotheses by incorporating these new tools and techniques.