Direct analysis of bone strain has provided functional morphologists with a technique to measure performance in a tremendous variety of behaviors. However, measurement in skeletal cartilage has been hampered by the inability to use strain gauges or similar tools. This research project will use a novel approach, sonomicrometry, to investigate the function of cartilage as a structural material in cartilaginous vertebrates. Preliminary research shows that sonomicrometry, which uses ultrasound to measure deformation, can be used successfully to measure strain in cartilage. The research will advance our knowledge and understanding about the function of cartilage as a structural material in vertebrates by quantifying strain during in vitro and in vivo loading. The study will also open multiple avenues of study on other biological materials that are not amenable to traditional strain analysis.

A broad range of chondrichthyan and chondrostean fishes that vary morphologically and kinematically in jaw and hyoid structures will be studied during feeding and ventilation behaviors with five aims. Morphological variation will be quantified using 3D geometric morphometrics. Mechanical properties will be measured in vitro to provide baseline data to assess the function of cartilage as a structural material. Strain in living fishes will be measured to examine cartilage performance as a skeletal element, providing a technique and baseline for measuring strain in non-bony skeletal elements. Finite element analysis will be validated from in vivo species and used to predict strain in those species or structures that are not amenable to in vivo techniques. Cartilage performance, behavior, and morphology will be analyzed phylogenetically to uncover ecological and evolutionary patterns. A research fellow, two graduate students and at least seven undergraduate students will receive research training in all aspects of the study, from data collection to publication. The project will also include K-12 outreach, science teacher-training and undergraduate education. FE models produced during the study will be archived in the publically accessible BIOMESH database (http://www.biomesh.org/).