Meeting Abstract

30.2  Jan. 5  Behavior and Morphology of Aquatic Feeding in Pipid Frogs CARRENO, C.A.*; NISHIKAWA, K.C.; Northern Arizona University; Northern Arizona University cac36@nau.edu

Feeding behavior and morphology was examined in the pipid frogs, Pipa pipa, Xenopus laevis, Hymenochirus curtipes, and Pseudhymenochirus merlini. Direct measurements of buccal cavity pressure during prey capture recorded localized pressure changes. For each species, the internal buccal pressure was found to drop significantly below ambient, and high-speed digital imaging revealed that pressure changes corresponded to gape cycles. Pipa pipa and X. laevis employed forelimb scooping in addition to suction feeding, but H. curtipes and P. merlini used suction feeding exclusively. The kinematics of suction feeding in the pipid frogs was compared to other suction feeding vertebrates as well as lingual feeding anurans. Species of pipids were not kinematically distinct, but each species consistently exhibited a wave of buccal expansion, similar to other aquatic vertebrates. The feeding behavior of pipid frogs is functionally convergent with other suction feeding vertebrates, and not phylogenetically constrained. The morphology and mechanics of the feeding apparatus was examined using buccal molds, clearing and staining, and gross dissection. The buccal cavity was found to be greatly enlarged, and extended posteriorly. Cleared and stained specimens showed that the hyoids are expanded and shifted posteriorly to support the buccal cavity. The feeding musculature is modified to produce expansion of the buccal cavity by retraction and depression of the hyoid. The morphology of the feeding apparatus in pipid frogs was found to be modified from typical anurans and has characteristics of suction feeding vertebrates.