The metamorphosis of feeding kinematics in Salamandra salamandra and the evolution of terrestrial feeding behavior

Abstract

The striking similarity between aquatic feeding behaviors in fishes and tetrapods and terrestrial prey transports in tetrapods and their contrasts to terrestrial tongue projection kinematics have led to a general hypothesis that terrestrial prey capture evolved from terrestrial prey transport, which, in turn, evolved from aquatic feeding behavior. This hypothesis is examined in Salamandra salamandra by comparing the kinematics of prey capture and transport before and after metamorphosis in the same group of eight individuals. Kinematics of aquatic and terrestrial strikes and transports are used to describe the metamorphosis of feeding behavior in S. salamandra and provide the first kinematic description of both aquatic and terrestrial feeding behaviors in the family Salamandridae. On the basis of the shared characteristics among the four behaviors, the two aquatic behaviors are most similar, and these are more similar to terrestrial transports than to terrestrial strikes. Given the ontogenetic polarity of these behaviors in salamanders, I suggest, on the basis of the shared similarities and functional shifts, that terrestrial transport is an intermediate behavior between aquatic feeding and terrestrial tongue projection. These results support the hypothesis that a shift from aquatic feeding to terrestrial transport to terrestrial tongue projection represents an evolutionary transformation series in the evolution of terrestrial feeding in early tetrapods.