Meeting Abstract
Lateral undulation of the vertebral column is an important characteristic of sprawling postured tetrapod locomotion. The goal of this study was to determine the role of the lateral movement of the trunk vertebrae in terrestrial locomotion of tiger salamanders (Ambystoma tigrinum). This was done by artificially limiting trunk flexibility by attaching a 2-piece “shell” around the body between the pectoral and pelvic girdles. Adult tiger salamanders (n =3, SVL = 9 cm-14.5 cm) walked on a 1 m trackway under three different conditions: no shell, flexible shell (tygon tubing), and rigid shell (PVC tubing). Trials were filmed in a single, dorsal view using a Kodak Playsport camera (30 fps). Kinematic markers were located on the wrist, elbow, and shoulder joints of the forelimb. A custom-written MATLAB program was used to track the midline and the forelimb movements of the salamanders and analyze kinematic variables. Average and maximum curvatures over (1) the entire midline and (2) restricted trunk/tail regions were compared over multiple strides. Curvature over the whole midline was higher in the flexible and rigid shell treatments compared to the control. This trend seems to be driven by an increase in curvature in the tail region, perhaps to compensate for the shells. Curvature in the trunk region was lower for the rigid shell treatment compared to the flexible shell and control. The reduction of lateral flexion results in one region of the body results in compensatory movements in other regions.
