Meeting Abstract
Diverse fish taxa of small body size move on land by means of coordinated tail-flips. In this behavior, the starting position is either lying on the fish’s side or ventral surface, and the head and body are lifted over the tail as the body curls into a C shape. While the tail pushes against the substrate, continuation of the movement of the anterior portion of the body propels the fish into ballistic flight in the original direction of the tail. While representatives of multiple fish orders are capable of tail-flipping (e.g., Cypriniformes, Perciformes, Cyprinodontiformes, Blenniformes), not all tail-flippers are equally adroit. The most effective tail-flip jumpers (e.g., mangrove rivulus, Kryptolebias marmoratus, and the Pacific leaping blenny, Alticus arnoldorum) also demonstrate the ability to twist the tail about the long axis up to 90°, which allows the jump to begin from a prone position. How are these fish able to twist the tail to such an extent? We experimentally twisted the tails of less and more effective tail-flip jumpers, finding that in less skilled jumpers, the tail rotates only to a maximum of ~45°. We used CT scans of effective tail-flipping species that had been fixed in the tail-twisted position to examine where the ability to generate long-axis torsion resides. In K. marmoratus, tail twisting is distributed over most of the length of the vertebral column, with no obvious specializations of the vertebrae. This finding suggests that soft tissues may play a central role in determining vertebral flexibility.
