UNDER PRESSURE - FINITE-ELEMENT ANALYSIS OF CRUSHING PREDATION ON BIVALVE SHELLS

Shell morphologies such as spines, overlapping or interlocking shell margins, strong hinge teeth, and strong radial strengthen the shell have widely been hypothesized to increase the ability to withstand crushing predation. However, not much data is available quantifying how bivalve shell symmetries can act as defensive morphology against crushing predation. In this study we model the mechanical characteristic of different shell symmetries under pressure, simulating durophagous predatory attacks, using Finite-element analysis (FEA). FEA is a standard engineering technique that enables us to examine how complex objects resist load and to reconstructed deformation, stress and strain in digital structures.

To be able to generate realistic models, key variables such as the mechanical properties, symmetries of the shell, forces produced by crushing predators, and the manner in which these are applied to the shells, have to be provided. We establish these parameters using modern Atlantic bivalve taxa and crab predator simulating their predatory interactions. The shell geometry of the prey organisms is captured by three dimensional surface scans and the physical properties of shell and claw materials will be added by nanoindentation tests, a method proven to be a powerful tool for understanding the structure and mechanical property of biological materials such as e.g., fish teeth and scales, abalone shell, and other arthropod exoskeletons.

Where, in the past, mechanical experiments simulating predatory attacks utilized, for example, steel bars in Instron testing machines to crush bivalve prey, measuring the tension or compression applied to a given surface, computer models now allow the exact simulation of these processes. These new technologies and virtual methods have the potential to provide novel insights and are thought to be important new venues in paleontology in the coming years; here we aim to establish this technique to answer research question regarding fossil invertebrate organisms.