Meeting Abstract

7.6  Thursday, Jan. 3  Aquatic and terrestrial locomotion of the ropefish (Erpetoichthys calabaricus). PACE, C. M.*; GIBB, A. C.; Northern Arizona University; Northern Arizona University Cinnamon.Pace@nau.edu

The ropefish, Erpetoichthys calabaricus, is an elongate fish known to make terrestrial excursions. Another elongate amphibious fish, the eel (Anguillidae), uses distinct kinematic patterns of movement when on land and in the water. We hypothesize that, like eels, ropefish will use �swimming undulation� in the water and �lateral undulation� on land. To compare movements across habitats, ropefish aquatic and terrestrial locomotor trials were captured using digital imaging. The midline of the fish was tracked with a custom digitizing program and body movements were plotted over time. Nested ANOVA revealed differences in the degree of bending across habitats (p<0.05); post-hoc tests indicated that ropefish demonstrate differences in bending between body segments during aquatic locomotion (p<0.05), but not during terrestrial locomotion (p<0.14). Thus, during aquatic locomotion there is a gradient from low amplitude undulations at the anterior end of the animal to high amplitude undulations at the posterior end of the animal, as a traveling wave is propagated along the body. This pattern of �swimming undulation� is seen in eels and other ray-finned fishes. Ropefish terrestrial locomotion, in contrast, more closely approximates �lateral undulation� (as originally described for snakes). In this mode of locomotion, there is no progressive increase in wave amplitude down the body, instead traveling waves are used to push against surface irregularities. Our preliminary analysis suggests that ropefish use similar modes of locomotion to eels when on land and in the water. This suggests that elongate fishes may move similarly on land irrespective of phylogeny.