Meeting Abstract

40.6  Monday, Jan. 5  Paired fin-based locomotion in the lungfish KING, HM*; HALE, ME; Univ. Chicago; Univ. Chicago hking@uchicago.edu

Lungfish are one of only two extant non-tetrapod sarcopterygian taxa, the other being coelacanths, and are of interest to biologists from anatomical, physiological and evolutionary perspectives. Despite this, little is known of their locomotion, particularly locomotion involving the paired pectoral and pelvic fins. In order to better understand diversity of locomotor modes in the Sarcopterygii, we examined paired fin and axial movement in the African spotted lungfish (Protopterus annectens). Because of the importance of hindlimb-driven locomotion in coelacanths and tetrapods, we focused on the patterns of pelvic fin movement. Spontaneous swimming and investigator-initiated startle responses were filmed in a still tank at 60Hz. A ventral view was used to determine limb/axial patterns and a lateral view was used to determine the location of the fish in the water column. We found a broad diversity of coordination patterns between the paired fins, and the paired fins and axis. The pelvic fins were used frequently to move along the bottom of the tank and, in some locomotor bouts, were coordinated with axial undulation. Both alternating and synchronous pelvic fin gaits were used. The pectoral fins were more active when the fish was swimming higher in the water column. During high speed swimming, as after a startle response, pectoral and pelvic fins were tucked and the fish was propelled by axial undulation alone. While pelvic fin-based locomotion is rare in ray-finned fishes, our finding that pelvic fins are key propulsors in lungfish demonstrates the importance of pelvic fins locomotion across the major sarcopteryigan lineages. Beyond the pelvic fins, lungfish have a rich diversity of gaits, making them an interesting group in which to examine control, coordination and evolution of sarcopterygian locomotion. Supported by NSF grant IBN0238464 to MEH.