Meeting Abstract
Evolution of the feeding apparatus in ray-finned fishes has been dominated by a trend of increased jaw mobility, or kinesis. This research focuses on the relationship between cranial morphology and feeding kinesis in the trophically diverse cichlids of the East African rift lakes, Malawi and Tanganyika. We used geometric morphometrics to quantify feeding kinesis as trajectories of shape change through morphospace. Analyses were based on 326 videos of feeding strikes from 56 cichlid species, recorded at 2,000 frames per second. We evaluated the magnitude of kinesis achieved during strikes and also developed a metric of kinematic efficiency, which is related to the conservation of shape change during feeding. We found that both metrics were significantly related to head shape, where species with larger mouths and elongate heads had more dynamic and efficient strikes than species with stout heads and shorter jaws. These patterns of morphological and kinematic variation were also related to feeding ecology, with increasingly evasive prey types associated with greater kinesis and more motion-efficient strikes. Our results indicate that a tight linkage between cichlid morphological diversity and feeding ecology that is mediated by the functional demands associated with capturing preferred prey.
