Meeting Abstract
The functional design of actinopterygian cranial musculoskeletal systems and its contribution to aquatic prey capture has been the subject of study for nearly two centuries. Even today, the complex kinematic basis and physiological determinants of fish feeding behavior remains an active and productive area of comparative research. Most fishes rely on inertial suction to overtake a prey item, a behavior reliant upon the rapid expansion of the oral cavity. While buccal expansion has been described as organizationally complex, models of buccal compression remain relatively simple. In particular, the musculoskeletal elements associated with jaw adduction in most fishes adheres to a third-order lever model. Accordingly, adductor muscles actuate jaw closing by applying force to an in-lever some distance from the jaw joint. In this study, we considered to what degree the organizational complexity of the adductor muscle system has in jaw closing performance. Through biomechanical modeling of jaw-adduction systems in three species of teleosts, we reveal that the architectural design of adductor muscle-tendon units imparts an ability to dynamically alter the mechanical advantage of major inputs to the lower-jaw lever system. Specifically, we show that a division of adductor muscle system—the Aω—may play a role in applying adduction torques to more distal positions along the lower jaw, thus increasing mechanical advantage. The role of dynamic mechanical advantage brought on by this design is discussed in terms of behavioral responses to feeding requirements and the performance tradeoffs dictated by different prey types.
