Meeting Abstract
11.4 Monday, Jan. 4 Locomotion in catfishes: are catfishes exapted for walking on land? PACE, C. M.*; GIBB, A. C.; VAN WASSENBERGH, S.; Northern Arizona University; Northern Arizona University; University of Antwerp Cinnamon.Pace@nau.edu
Walking catfishes are known to move on land; however, key questions about this behavior remain unanswered: (1) how do walking catfish produce forward movement on land? (2) how similar is terrestrial locomotion among walking catfishes? (3) is terrestrial locomotion distinct from aquatic catfish locomotion? and (4) is terrestrial locomotion distinct from the terrestrial movements of nonwalking catfishes? We recorded dorsal views of two walking catfishes (Clarias batrachus and Clarias garieppinus) moving terrestrially, a nonwalking catfish (Ictalurus punctatus) moving terrestrially, and a walking catfish (C. batrachus) swimming. Terrestrial locomotion appears similar in the two walking catfish species and distinct from both swimming in C. batrachus and terrestrial locomotion in I. punctatus. Terrestrial locomotion of Clarias sp. is characterized by contact between a pectoral fin spine and the ground, while the axial musculature and tail push against the ground to elevate the catfish over the spine. Pectoral fins are adducted during the aerial (swing) phase and subtends an arc >70°. The tail oscillates twice during each pectoral fin stride and the tip is placed far anteriorly. In contrast, during swimming the pectoral fin moves <30°, while the body axis and caudal fin produce carangiform undulation. The nonwalking catfish was ineffective in generating forward movement and its pectoral fins did not engage with the ground, although the pectoral girdle oscillated and the tail produced a similar tail motion to that of walking catfishes. This suggests that emergence may elicit a similar motor pattern for many catfishes, but it is the addition of effective pectoral spine movements that enables forward propulsion to occur during terrestrial locomotion.
