Body shape separates guilds of rheophilic herbivores (Myleinae: Serrasalmidae) better than feeding morphology
Body shape separates guilds of rheophilic herbivores (Myleinae: Serrasalmidae) better than feeding morphology
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DOI：
10.1635/053.166.0116
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发表时间：
2020-11-01
影响因子：
0.7
通讯作者：
Kolmann, Matthew A.
中科院分区：
文献类型：
--
作者：
Huie, Jonathan M.;Summers, Adam P.;Kolmann, Matthew A.
草食性鱼类以各种水生植物的茎、叶、花、种子、果实和坚果以及藻类为食。Pacus是食人鱼的食草近亲，以这些植物产品为食，但也有一些是植食性动物，它们几乎只以Podostemaceae家族的水生植物（嗜流）为食。pacus以河草为食的程度各不相同，从强制性的全年食用到严格的季节性兼性食用。专性噬菌体主要以河草为食，并严格发生在急流中，而兼性噬菌体只在流量低的季节消耗河草。生态特化（饮食）是否会导致植噬体摄食器官和/或体型的形态特化？在系统发育框架下，我们利用微计算机断层扫描（mu CT）比较了26种serrasalmids的功能摄食特征，其中4种是专性噬菌体。我们还使用几何形态计量学比较了pacus之间的体型，以确定对流变的潜在运动适应。专性植噬体与其他pacus相比，具有牙齿和切颚，非常适合剪切肉质植物材料，具有果实和种子的粉碎形态。不相关的专性植噬体也聚集在一个类似的身体形状，不同于同域的同类食草动物。植物噬食性涉及到更一致的身体形状的变化，而不是喂养形态的变化，这表明身体形状与食物有更重要的联系
Herbivorous fishes feed on stems, leaves, flowers, seeds, fruits, and nuts of diverse aquatic plants, as well as algae. Pacus are the herbivorous cousins of piranhas and consume a myriad of diets comprised of these plant products, but a few species are phytophages, herbivores that feed almost exclusively on rapids-dwelling (rheophilic) riverweed plants from the family Podostemaceae. The degree to which pacus feed on riverweed varies from obligate year-round consumption to strictly seasonal, facultative feeding. Obligate phytophages feed heavily on riverweed and strictly occur in river rapids, while facultative phytophages only consume riverweed during seasons with low flow. Does ecological specialization (diet) beget morphological specialization in the feeding apparatus and/or body shape of phytophages? Under a phylogenetic framework, we used microcomputed tomography (mu CT) scanning to compare functional feeding traits among 26 species of serrasalmids, four of which are obligate phytophages. We also compared body shape between pacus using geometric morphometrics to identify potential locomotor adaptations for rheophily. Obligate phytophages have dentitions and slicing jaws well-suited for shearing fleshy plant material relative to other pacus, which are equipped with fruit and seed crushing morphologies. Unrelated obligate phytophages have also converged on a similar body shape that is distinct from sympatric congeneric herbivores. Phytophagy involves more consistent changes to body shape than to feeding morphology, suggesting that body shape has more important ties to