Comparative kinematics of terrestrial prey capture in Salamanders and newts (Amphibia:Urodela:Salamandridae)

Abstract

AbstractHigh‐speed cinematography was used to compare the kinematics of terrestrial prey capture among postmetamorphic individuals of the family Salamandridae that have a) terrestrial (Salamandra, Salamandrina, and Tylototriton), b) amphibious (Pleurodeles, Cynops, and Paramesotriton), and c) aquatic (Pachytriton) lifestyles. Tongue projection was common during prey capture attempts in Salamandra, Salamandrina, and Tylototriton, occurred frequently in Cynops and Paramesotriton, but was absent during terrestrial feeding by Pachytriton. The gape cycle consisted of four distinct phases that were associated with discrete movements of the hyolingual apparatus. In all salamandrids that projected the tongue, the gape 1) increased rapidly while the tongue was elevated from the floor of the mouth in preparation for protraction, 2) was stabilized while the tongue was protracted, 3) increased to maximum during retraction and 4) decreased rapidly while the tongue transported the prey into the oral cavity. The absence of tongue projection during some (Cynops, Paramesotriton), or all prey capture attempts (Pachytriton) resulted in gape profiles distinctly different from those described above. Most notably, these profiles lacked the gape stabilization component characteristic of tongue projection. The maximum distance that the tongue was projected beyond the mandible approached 6% snout‐vent length (SVL) in most salamandrids, but reached 20% SVL in Salamandrina. Several elements of the feeding system in Salamandrina are functionally related to the evolution of its specialized tongue projection apparatus. These include a gape cycle of relatively long duration (200 ms) and the absence of a head‐body surge and of eye retraction during the strike.