Linking Characteristics of Stance and Swing Phase Muscles With Ecology, Morphology and Locomotor Performance in the Lizard, Sceloporus woodi

A question that has intrigued scientists for quite some time is how muscle physiology relates to locomotor performance and ecology. For lizards, the iliofibularis, a swing phase muscle, if often the single muscle studied when addressing related questions. Although this previous work has contributed to our understanding of muscle function in lizards, locomotor performance depends strongly on the contribution from propulsive (stance phase) muscles. Thus, we examined fiber type, fiber diameter, and muscle cross sectional area of both swing (including the iliofibularis) and stance phase hindlimb muscles in the lizard, Sceloporus woodi . To assess the influence of ecology, we captured individuals from two types of habitats in the Ocala National Forest in Florida. Prior to examining muscle parameters, we obtained high-speed video (500fps) of each lizard running maximally on a level 1-meter raceway. We also filmed the lizards running vertically on a branch at 300fps. Each lizard was run on each apparatus a minimum of three times and the maximum value across all three trials was retained for analysis. These detailed morphological and performance data will be examined in light of variation in habitat characteristics and the extensive existing literature on lizard locomotion.