METHOD DEVELOPMENT IN BIOMIMETIC MODELS USING 3D PRINTED MATERIALS

Around 350 million years ago, Earth’s ecology was revolutionized when vertebrates left aquatic environments and invaded the terrestrial realm. This transition was challenging: terrestrial biomes were three-dimensionally complex heterogeneous landscapes containing obstacles such as fallen logs, stones, and uneven slopes. Previous biomechanists have investigated movement between water and land in living fishes and salamanders, focusing on behavioral tail usage and changes in muscle activation. However, neither of these metrics are preserved in the fossil record; rather changes in the shape of skeletal elements like vertebrae are assumed to be linked to terrestrial lifestyles and used to date the tetrapod invasion of land. To test morphological and functional hypotheses surrounding this event, we experimentally designed physical models of the vertebral column. This is a powerful technique for evaluating difficult or hypothetical (not present in modern analogues) morphologies, as these can reveal the existence of variables and outcomes not predicted in computer simulations. However, there are many difficulties and factors to consider when creating a biomimetic model with extinct taxa, such as the approximating the material properties of bone and cartilage and inferring realistic range of motion. We have dealt with these issues and developed a workflow designed to objectively capture and test the effects of spinal morphology on locomotion. We used computed Tomography of fossil vertebrae to create simplified functional 3D models based on standardized metrics. These are then printed and used in physical experimentation on the spinal morphology of different early tetrapods. This technique provides a standardized method to bring extinct taxa back to life for biomechanical testing.