Martinez Christopher M, McGee Matthew D, Borstein Samuel R, Wainwright Peter C
Department of Evolution and Ecology, University of California, Davis, California 95616.
School of Biological Sciences, Monash University, 3800 Victoria, Australia.
Evolution. 2018 Jun 19. doi: 10.1111/evo.13518.
The fish feeding apparatus is among the most diverse functional systems in vertebrates. While morphological and mechanical variations of feeding systems are well studied, we know far less about the diversity of the motions that they produce. We explored patterns of feeding movements in African cichlids from Lakes Malawi and Tanganyika, asking whether the degree of kinesis is associated with dietary habits of species. We used geometric morphometrics to measure feeding kinesis as trajectories of shape change, based on 326 high-speed videos in 56 species. Cranial morphology was significantly related to feeding movements, both of which were distributed along a dietary axis associated with prey evasiveness. Small-mouthed cichlids that feed by scraping algae and detritus from rocks had low kinesis strikes, while large-mouthed species that eat large, evasive prey (fishes and shrimps) generated the greatest kinesis. Despite having higher overall kinesis, comparisons of trajectory shape (linearity) revealed that cichlids that eat mobile prey also displayed more kinematically conserved, or efficient, feeding motions. Our work indicates that prey evasiveness is strongly related to the evolution of cichlid jaw mobility, suggesting that this same relationship may explain the origins and diversity of highly kinetic jaws that characterize the super-radiation of spiny-rayed fishes.
鱼类摄食器官是脊椎动物中最多样化的功能系统之一。虽然摄食系统的形态和力学变化已得到充分研究，但我们对它们所产生运动的多样性了解得要少得多。我们探究了马拉维湖和坦噶尼喀湖非洲丽鱼科鱼类的摄食运动模式，研究运动程度是否与物种的饮食习惯有关。我们基于56个物种的326段高速视频，运用几何形态测量学将摄食运动作为形状变化轨迹来测量。颅骨形态与摄食运动显著相关，二者都沿与猎物逃避性相关的饮食轴分布。通过刮食岩石上的藻类和碎屑进食的小嘴丽鱼科鱼类的运动撞击程度较低，而捕食大型、逃避性猎物（鱼类和虾类）的大嘴物种产生的运动撞击程度最大。尽管总体运动程度较高，但对轨迹形状（线性）的比较显示，捕食活动猎物的丽鱼科鱼类也表现出运动学上更保守或更高效的摄食运动。我们的研究表明，猎物逃避性与丽鱼科鱼类颌骨活动能力的进化密切相关，这表明这种相同的关系可能解释了以多刺鳍鱼类的超级辐射为特征的高度灵活颌骨的起源和多样性。
