Meeting Abstract
Studies of vertebrate feeding have, quite reasonably, focused on the bones and muscles of the head, not the body. Yet, postcranial structures like the spine and pectoral girdle are anatomically linked to the head, so there may also be mechanical connections through which these musculoskeletal systems contribute to feeding. The role of postcranial structures during feeding has been best studied in ray-finned fishes, where the body muscles attach directly to the head and actively shorten to expand the mouth. Therefore, I used the anatomy and motion of the head-body interface in fishes to develop a mechanical framework for studying postcranial functions during feeding. In fish the head and body are linked by the vertebral column, the pectoral girdle, and the body muscles that actuate these skeletal systems. The joints and muscles of the cranio-vertebral and pectoral interfaces may have distinct morphologies, which in turn determine the mobility of the head relative to the body. The postcranial interfaces can function as anchors during feeding: the body muscles and joints minimize motion between the head and body to stabilize the head, or transmit forces from the body. Alternatively, the postcranial interfaces can be motors: body muscles actuate motion between the head and body to generate power for feeding motions. The motor function is likely important for many suction-feeding fishes, while the anchor function may be key for bite- or ram-feeding fishes. This framework can be used to examine the role of the postcranial interface in other vertebrate groups, and that role changes (or not) with morphology and feeding behaviors. Such studies can expand our understanding of muscle function, as well as the evolution of vertebrate feeding behaviors across major transitions such as the invasion of land and the emergence of jaws.
