Meeting Abstract
P1.104 Tuesday, Jan. 4 Modifications of the vertebral column for enhanced energy storage in jumping fish ASHLEY-ROSS, MA*; LONG, JH; GIBB, AC; Wake Forest University; Vassar College; Northern Arizona University rossma@wfu.edu
Videler (1993) predicted that the amount of energy stored upon deformation and subsequently released is directly correlated with the angle of inclination of the neural/hemal spines. If unrestrained, the further the deviation from perpendicular, the more the spines would depart from the midsagittal plane as the vertebral column bends. During bending connective tissue in the vertical septum prevents the neural/hemal spines from moving out of plane, and as a result, the spines are bent. Flexion of the vertebral column thus leads to elastic strain energy storage by the bony spines. While Videler considered aquatic locomotion, the same principles apply to fish caught on land who leap by bending the body and pushing off with the tail. Accomplished jumpers are predicted to have neural/hemal spines with more acute angles to the vertebral axis, and more robust hypurals, than poor jumpers. Comparison of the vertebral columns of Gambusia (good jumper) versus Danio (poor jumper) confirms some predictions, but not others. The caudal fin skeleton of Gambusia is more robust than that of Danio, with fusion of the central hypurals into a stiff fan. Both neural and hemal spines in Danio show more curvature than in Gambusia. However, the angles of the neural/hemal spines are less acute in Gambusia than in Danio, contrary to Videler’s contention. Potentially offsetting this counterintuitive result, the neural and hemal spines of Gambusia are relatively longer, and span more intervertebral joints, than their counterparts in Danio. Therefore Gambusia’s vertebral spines may store more elastic strain energy than Danio’s due to longer length, and the stiffer tail skeleton likewise may store more energy upon deformation, leading to enhanced mechanical power returned during the propulsive phase of the jump.
