Jumping in arboreal salamanders: A possible tradeoff between takeoff velocity and in-air posture

Jumping performance can have important implications for an animal's fitness by expanding its ability to evade predators and move between microhabitats. Jumping in terrestrial plethodontid salamanders is achieved through lateral bending and rapid unbending of the trunk, an action powered by axial musculature. Arboreal plethodontids, some of which are known to occupy tree crowns, tend to have more robust limbs and longer digits, which may affect their jumping kinematics and performance. We examined jumping kinematics in ten species of plethodontid salamanders, including four arboreal species of the genus Aneides, using high speed imaging and kinematic analysis. Salamanders of the genus Aneides exhibit lower takeoff velocities when compared with the terrestrial plethodontids Eurycea, Desmognathus, and Plethodon, possibly due to reduced trunk bending. Aneides also exhibit higher frequencies of two-footed takeoffs, and often orient their feet to launch from vertical surfaces when presented with the option. This suggests an alternative jumping behavior in salamanders that may reflect an arboreal lifestyle. All plethodontid species examined displayed distinctive in-air parachute postures after 45-100% of descending jumps, with Aneides showing the highest frequency of this behavior.