Kolmann Matthew A, Huie Jonathan M, Evans Kory, Summers Adam P
Friday Harbor Laboratories, University of Washington, 620 University Road, Friday Harbor, WA 98250, USA.
School of Aquatic and Fishery Sciences, University of Washington, 1122 NE Boat St, Seattle, WA 98195, USA.
R Soc Open Sci. 2018 Jan 17;5(1):171581. doi: 10.1098/rsos.171581. eCollection 2018 Jan.
Although rare within the context of 30 000 species of extant fishes, scale-feeding as an ecological strategy has evolved repeatedly across the teleost tree of life. Scale-feeding (lepidophagous) fishes are diverse in terms of their ecology, behaviour, and specialized morphologies for grazing on scales and mucus of sympatric species. Despite this diversity, the underlying ontogenetic changes in functional and biomechanical properties of associated feeding morphologies in lepidophagous fishes are less understood. We examined the ontogeny of feeding mechanics in two evolutionary lineages of scale-feeding fishes: , a characin, and , a piranha. We compare these two scale-feeding taxa with their nearest, non-lepidophagous taxa to identify traits held in common among scale-feeding fishes. We use a combination of micro-computed tomography scanning and iodine staining to measure biomechanical predictors of feeding behaviour such as tooth shape, jaw lever mechanics and jaw musculature. We recover a stark contrast between the feeding morphology of scale-feeding and non-scale-feeding taxa, with lepidophagous fishes displaying some paedomorphic characters through to adulthood. Few traits are shared between lepidophagous characins and piranhas, except for their highly-modified, stout dentition. Given such variability in development, morphology and behaviour, ecological diversity within lepidophagous fishes has been underestimated.
尽管在现存的3万种鱼类中较为罕见，但作为一种生态策略，食鳞行为在硬骨鱼的生命之树上反复进化。食鳞鱼在生态、行为以及用于啃食同域物种鳞片和黏液的特殊形态方面具有多样性。尽管存在这种多样性，但对于食鳞鱼相关摄食形态的功能和生物力学特性在个体发育过程中的潜在变化却知之甚少。我们研究了两个食鳞鱼进化谱系——一种脂鲤科鱼类和一种食人鱼——摄食力学的个体发育过程。我们将这两个食鳞类群与其最近的非食鳞类群进行比较，以确定食鳞鱼共有的特征。我们结合使用微计算机断层扫描和碘染色来测量摄食行为的生物力学预测指标，如牙齿形状、颌骨杠杆力学和颌部肌肉组织。我们发现食鳞类群和非食鳞类群的摄食形态形成了鲜明对比，食鳞鱼在成年后仍表现出一些幼态特征。除了高度特化、粗壮的牙齿外，食鳞脂鲤科鱼类和食人鱼之间几乎没有共同特征。鉴于在发育、形态和行为方面存在如此大的变异性，食鳞鱼内部的生态多样性一直被低估。
