Meeting Abstract
S3-2.1 Saturday, Jan. 5 Feeding and swallowing on land VAN WASSENBERGH, S.*; MICHEL, K.; Univ. Antwerpen, Belgium; Univ. Antwerpen, Belgium sam.vanwassenbergh@ua.ac.be
An important step towards understanding the evolution of terrestriality in vertebrates is to identify how the aquatic ancestors of tetrapods were able to access ground-based prey. Since several extant lineages of bony fishes show an amphibious feeding lifestyle, these fishes can be used to study the biomechanical requirements of successful aquatic to terrestrial transitions to capture and transport prey in their buccopharyngeal cavity. We analyzed the functional morphology and kinematics of two morphologically distinct and distantly related species that are both successful terrestrial feeders: the mudskipper (Periophthalmus barbarus) and the eel-catfish (Channallabes apus). During prey capture, the mudskipper pivots over its strong pectoral fins, and uses its complex system of oral jaws to pick up pieces of food on land. Notably, we found that this species still makes use of water carried along in the buccopharyngeal cavity to assist prey capture, and to provide intra-oral transport of food towards the esophagus by performing suction movements. This mechanism is markedly different from the eel-catfish, which curls into a position where the head is strongly bended ventrally, scans the surface by moving its head and chemotactile barbels from side to side, and performs a typical rostro-caudal wave of buccopharyngeal expansion of the jaws, hyoid and opercular system (as in most suction feeding fish). These findings show that having weightbearing pectoral fins is not a prerequisite for capturing prey on land in a fish that has a flexible body. Unlike the mudskipper, the eel-catfish does not use a hydrodynamic tongue to swallow the prey, but returns to the water to perform the necessary food transport. Consequently, these examples show two clearly different strategies to overcome the problems imposed by the shift from an aquatic to a terrestrial environment for feeding.
