Meeting Abstract
Skates are known to locomote using the anterior lobe, or crura, of their pelvic fins to push off the substrate. Skates have two non-swimming locomotor modes: “walking” via alternating pelvic fins, and “punting”, which uses simultaneous bilateral movements of their pelvic fins. It has recently been shown that the Hox genes responsible for limb development in the little skate, Leucoraja erinacea, are the same as those found in terrestrial vertebrates (i.e. mice). Previous studies showed the morphology of the pelvic girdle and the kinematics of walking resemble that of a sprawled-gait terrestrial tetrapod (i.e. salamanders). The next step to understanding the locomotion employed by skates is to investigate neuromotor control of the muscles. The pelvic area of L. erinacea (puboischiadic bar, fins, and spinal column) was µCT scanned to observe the skeletal elements. The area was then stained with phosphotungstic acid (PTA) and rescanned to visualize the musculature. These scans were reconstructed with Mimics software and used to create and animate a morphologically-based 3-D digital model in the program Maya. The physiological cross-sectional area (PCSA) of the muscles was calculated and the maximum force generation of each muscle involved in locomotion was estimated to use as parameters in the model. This model allowed us to simulate different aspects of muscle stimulation/timing and to investigate the kinematics, biomechanics, and motor modulation of both walking and punting. These data will be used in future projects to compare the model to electromyography (EMG) of in vivo little skate muscles.
