Meeting Abstract

P3.136  Monday, Jan. 6 15:30  Role of Lateral Undulation in Salamander Locomotion VEGA, CM*; ASHLEY-ROSS, MA; Wake Forest University vegacm11@wfu.edu

With the exception of turtles, lateral undulation of the vertebral column is an important characteristic of sprawling-postured tetrapods’ locomotion. To elucidate the contribution of lateral undulation in swimming, underwater walking and terrestrial walking, we experimentally reduced vertebral flexibility in tiger salamanders (Ambystoma tigrinum) to mimic the condition in turtles. Three adult tiger salamanders (n =3) swam, walked underwater, and walked on land under each of three conditions: with nothing attached (baseline), with flexible tygon tubing around the trunk (control), and with rigid PVC pipe around the trunk (experimental). The tygon and PVC tubing was cut into half circles and fit over the mid-body of the salamanders between the fore and hind limbs, thus forming a “shell” that restricted lateral movement of the vertebral column to greater or lesser degrees. Two high speed cameras (Fastec TroubleShooter HR, 250 fps) captured dorsal and lateral views for kinematic analysis. Electromyography (EMG) was used to determine which muscles are active during aquatic and terrestrial walking and whether the activity patterns, timing, or intensity change when vertebral flexibility is eliminated. The five muscles targeted for EMG were as follows: (1) the dorsalis trunci; (2) the triceps; (3) the deltoid; (4) the pectoralis; and (5) the coracobrachialis (6) the latissimus dorsi. The same muscles will be targeted for EMG in turtles providing a basis for a direct comparison of their movement patterns in an aquatic and terrestrial environment. The comparative salamander data will be used to provide a context for comparison to turtles’ movement patterns to provide insight into their debated evolutionary history.