Meeting Abstract
Salamanders use the hyobranchial apparatus to depress the floor of the mouth during aquatic suction feeding and to project the tongue from the mouth during terrestrial feeding. We hypothesized that morphological and functional compromises in the hyobranchial apparatus will yield decreased prey capture performance for semi-aquatic species that feed in both air and water when compared to fully aquatic species. We found the fully aquatic newt, Paramesotriton labiatus, has increased mineralization of the hyobranchial apparatus, as well as relatively more robust ceratobranchial I + II complexes and epibranchials, compared to semi-aquatic newts, and that this increased robustness is correlated with increased aquatic feeding performance. Maximum hyobranchial depression acceleration was found to be approximately three times greater than in semi-aquatic species, at 50 m/s/s. Particle image velocimetry revealed peak and average fluid velocities generated during suction feeding events (0.6 m/s and 0.2 m/s, respectively) were more than double those produced by all semi-aquatic species. These findings reveal that a more robust hyobranchial apparatus increases aquatic feeding performance in a fully aquatic newt and accompanies specialization for suction feeding.
