Meeting Abstract

79.6  Friday, Jan. 6  The effect of tail autotomy on locomotor stability in the green anole lizard HSIEH, S. Tonia*; FISHER, Rebecca E.; KUSUMI, Kenro; Temple University, Philadelphia, PA; University of Arizona College of Medicine-Phoenix, AZ; Arizona State University, Tempe, AZ; Arizona State University, Tempe, AZ sthsieh@temple.edu

Having a tail in the animal kingdom is common; yet, the function of such a prevalent structure is not entirely understood. Recent work has shown that tails can be important for counteracting perturbations, and can affect maneuverability on level ground. The goals of this study were to quantify how tails are used during rapid locomotion and to determine how tail autotomy and regrowth subsequently affects locomotor mechanics. Regeneration was of interest because unlike the segmented, articulated vertebrae that compose the original tail, the regenerated tail comprises a single cartilaginous endoskeleton. We also have found that reorganization of musculoskeletal tissues in the tail stump takes place within days of autotomy in preparation for tail regeneration, which may affect its function. Data were collected from 10 adult male green anole lizards (Anolis carolinensis) running along surfaces of different diameters: flat (i.e., infinite diameter), 19.0 mm, 15.9 mm, and 9.5 mm, while tracking their body, limbs, and tail motions. Runs were filmed with a six-camera high-speed system (Motion Analysis, Corp) pre-, immediately after, and one week post-autotomy. We expected to find signatures of increased instability when running on narrow surfaces post-autotomy. Surprisingly, preliminary results show very few kinematic differences between pre- and post-autotomy running, with the greatest changes limited to the tail. Furthermore, the greatest differences were observed on the narrowest surfaces, which offer the greatest stability challenges to the running lizard. Together, these results suggest that the tail plays an important role in minimizing perturbations to the center of mass when running on narrow surfaces.