Meeting Abstract
Morphologists have long been challenged by presenting complex, 3-dimensional information in classical 2-dimensional projections for analysis and dissemination. Recent advances in capturing 3D data from the cranial or appendicular musculoskeletal system have certainly revolutionized the field, but we still are often relegated to presenting multiple, semi-redundant projections of jaw or limb muscle vectors in multiple planes of view, challenging readers’ translational aptitudes. Conventionally, the third dimension is just ignored, often when calculating simplified lever metrics of vertical bite force or ground reaction force for example, where mediolateral components of the system are considered negligible. But this lost component is critical to understanding numerous biomechanical and evolutionary patterns, particularly in the evolution of wide-skulled reptiles including lizards, crocodilians and dinosaurs. Significant changes in skull shape, in all 3 dimensions, can occur during individual feeding bouts involving significant cranial kinesis, during ontogenetic changes in skull shape, such as in the crocodilians, or across evolutionary time during the origins of modern birds and crocodylians. Here we show how projecting 3D vectors of jaw muscles in a ternary, or triangle plot conveys changes in muscle orientation and force across different passages of time and across different individuals and taxa and enables us to better understand patterns and processes of feeding behavior, ontogenetic shape change and morphological evolution. We are employing this approach to visualize archosaur and reptile jaw musculature, however its applications extend to most other parts of the musculoskeletal system.
