Meeting Abstract
Tide pool sculpins (Oligocottus maculosus) are intertidal fish that use terrestrial locomotion to move across land when stranded above the tideline. Our goals were to describe the kinematics of the terrestrial locomotion of O. maculosus and compare their terrestrial locomotion to their aquatic locomotion, the terrestrial locomotion of subtidal sculpin species (Leptocottus armatus and Icelinus borealis ), and the terrestrial locomotion of walking catfishes (Clarias spp.). We used high-speed video to record locomotion on terrestrial platforms and in water and landmark tracking software in MATLAB to analyze their body movements. O. maculosus use a previously undescribed form of axial-appendage-based locomotion, driven by lateral oscillations of the tail fin, synchronized with alternating body rotation about the base of the pectoral fins, which resembles a human “army crawl”. The terrestrial army crawl may originate from a modified series of aquatic fast starts (lateral bends), performed in a terrestrial environment. However, O. maculosus use axial undulation of the body during aquatic locomotion, whereas they appear to use axial oscillation in combination with their pectoral fins during terrestrial locomotion. In contrast, with O. maculosus, the subtidal sculpin species oscillate the tail from side to side, but do not make effective contact between the pectoral fins and the substrate. Because of this, they are able to move very slowly (if at all) when stranded on land. We note that O. maculosus have only subtle differences in morphology when compared with many subtidal species, which suggests that few morphological changes are necessary to produce effective terrestrial movements in this major lineage of teleosts.
