Meeting Abstract

76.2  Sunday, Jan. 6  Evolution of prey capture kinematics in centrarchid fishes WAINWRIGHT, P.C.**; MEHTA, R.S.; TRAN, H.Q.; ODUFALU, F.; Univ. of California, Davis pcwainwright@ucdavis.edu

How are prey capture kinematics modified during the evolutionary diversification of suction feeding fishes? Little is known about this process, and yet modifications to kinematics may accompany trophic specialization and morphological changes. We studied kinematic evolution by developing a data set on 17 species of centrarchid fishes from 500 Hz video recordings of them feeding on small ghost shrimp. Ten feeding events were filmed for each individual fish and species averages of 12 kinematic variables were calculated. A robust, time-calibrated phylogeny of the 17 species and body size corrected values of the averages were used to calculate standardized independent contrasts of the kinematic variables. A principal components analysis conducted on the kinematic contrasts produced a major axis of evolution (PC1 = 46% of variation) that loaded strongly and positively on all six kinematic timing variables. This axis confirmed the well-known tendency for conservation of the sequence of kinematic events that occur during suction feeding. The second PC (18%) involved a trade-off between peak gape distance and hyoid depression with maxillary and jaw rotation. Contrasts of Suction Index, a morphologically based measure of the capacity to generate suction pressure, were negatively correlated with PC6 (r = -.77), a trade-off between the time to peak hyoid and head elevation versus the time to peak gape, jaw depression and maxillary rotation. Since the sequence of kinematic events was highly conserved, this relationship reveals that stronger suction feeding capacity evolves in association with a shorter lag between mouth opening and buccal cavity expansion. Supported by NSF grant IOB-0444554.