Meeting Abstract
Largemouth bass, Micropterus salmoides, use suction feeding to capture prey. Water and prey are drawn in when the skull expands creating low pressure in the mouth towards which water flows. Recent studies have shown that axial muscles power expansion of the skeletal elements within the head to produce suction. Once produced, power is transmitted from the axial muscles throughout the highly kinetic cranial skeleton. The kinematics of cranial bones in M. salmoides have been studied extensively and the transmission of power has been modeled using mechanical engineering theory, but the connective tissues linking these bones have been omitted from most analyses. The goal of this study was to examine the histology of functionally relevant cranial joints and skeletal elements in M. salmoides including the interopercular-mandibular ligament and the hyomandibulo-opercular joint. Teleosts possess a spectrum of connective tissues with varying proportions of cells to extracellular matrix (ECM) as well as components of ECM. Here we characterize the types of connective tissues found within cranial joints. Studies have shown that elastic tissues in tetrapods may aid in power transmission by acting as biological springs, so we looked at elastin as a component of these linkages. We found that the hyoid bones are composed of chondroid bone, a tissue with cartilage-like cells embedded in a mineralized matrix. It has been suggested that chondroid bone may function to conserve energy by more readily transmitting forces incurred in suction feeding events. The diversity of teleostean connective tissues may play a larger role in power transmission – and perhaps amplification – throughout the cranial skeleton during suction feeding than previously thought.
