Meeting Abstract
P2.76 Wednesday, Jan. 5 Functional fin morphology of aquatic substrate-based locomotion in ogcocephalid fishes (Lophiiformes;Ogcocephalidae) RADE, CM*; WARD, AB; George Washington University; Adelphi University cristinarade@gmail.com
Most often, paired fins are associated with aquatic propulsion, maneuverability and stability within the water column; however, several species exhibit substrate-based locomotion in an aquatic environment including the pancake batfish, Halieutichthys aculeatus, and the polka-dot batfish, Ogcocephalus cubifrons. Prior research of benthic fishes reveal different ways in which substrate-based locomotion can be achieved, including movements of only pectoral fins or both sets of paired fins, as well as axial bending. For example, batfishes use their paired fins to exert forces on substrates to walk across the ocean floor; their fins are morphologically distinct from typical fish fins, and have been compared to tetrapod limbs. Furthermore, it has been suggested that the tetrapod limb may have evolved first for aquatic locomotion as a means of propulsion off substrates rather than for terrestrial locomotion. In consideration of these findings, the morphology and kinematics of the pancake and polka-dot batfishes have been examined to understand what similarities exist between the fins of benthic fishes and tetrapod limbs. Results indicate that the morphology of the batfish pectoral and pelvic fins are advantageous for substrate-based locomotion. For instance, the dorsoventral position of the batfish fins supports the body during walking. And, similar to tetrapod locomotion, appendage rotation is possible owing to the shape of the first radial bone and the attachment points of the inserting muscles. Analysis of digitized videos show that the paired fins are moving independent of one another in a diagonal-sequence gait and exhibit several characteristics of tetrapod locomotion including appendage retraction, “elbow” extension, and lateral axial movements. This work will provide an understanding of the unique and shared traits of fin-based walking and tetrapod locomotion.
