Lavoué Sébastien, Arnegard Matthew E, Rabosky Daniel L, McIntyre Peter B, Arcila Dahiana, Vari Richard P, Nishida Mutsumi
Institute of Oceanography, National Taiwan University, Roosevelt Road, Taipei 10617, Taiwan.
Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
Mol Phylogenet Evol. 2017 Aug;113:23-32. doi: 10.1016/j.ympev.2017.05.001. Epub 2017 May 3.
The African freshwater suborder Citharinoidei (Characiformes) includes 110 species that exhibit a diversity of feeding modes comparable to those characteristic of more speciose groups such its sister, the Characoidei (2000+ species) or the distantly related Cichlidae (1600+ species). Feeding habits of the Citharinoidei range from generalist omnivores to highly specialized feeding modes including ectoparasitic fin-eating, i.e. pterygophagy. We examine diet preference evolution in the Citharinoidei using newly inferred multi-gene-based hypotheses of phylogenetic relationships for representatives of 12 of the 15 genera in the suborder. Ancestral character state reconstructions onto our best tree indicate that the three most-generalist diets - pelophage/planktivore, omnivore and invertivore - are also the most primitive conditions within the Citharinoidei. The feeding mode of the most recent common ancestor of the Citharinoidei was characterized by high uncertainty. The more specialized feeding habits - herbivory, piscivory and pterygophagy - originated later in the Citharinoidei, likely from invertivore ancestors and possibly across a short time period. Highly specialized fin eaters (Belonophago, Phago and Eugnatichthys) share a common origin along with a strict piscivore (Mesoborus) and an invertivore (Microstomatichthyoborus). The largely piscivorous, but facultative fin eater, Ichthyborus is not exclusively related to them. Our results demonstrate that overall diet preference transitions in the Citharinoidei were rare events with very few reversals or parallelisms, and that evolutionary shifts in trophic ecology have not played a major role in intraordinal diversification. This situation contrasts with other groups in which dietary transitions have played key roles in species diversification.
非洲淡水亚目脂鲤亚目（脂鲤科）包含110个物种，其摄食模式的多样性堪比一些物种更为丰富的类群，比如它的姐妹类群脂鲤亚科（2000多个物种）或亲缘关系较远的丽鱼科（1600多个物种）。脂鲤亚目的摄食习性范围从杂食性到高度特化的摄食模式，包括体外寄生性的食鳍，即食鳍癖。我们利用新推断的基于多基因的系统发育关系假说，对该亚目15个属中的12个属的代表物种进行研究，以探讨脂鲤亚目的食性偏好演化。在我们构建的最优树上进行祖先性状状态重建表明，三种最具普遍性的食性——食浮游生物/浮游动物食性、杂食性和食无脊椎动物性——也是脂鲤亚目内最原始的状态。脂鲤亚目最近共同祖先的摄食模式具有高度不确定性。更为特化的摄食习性——草食性、食鱼性和食鳍癖——在脂鲤亚目中出现得较晚，可能起源于食无脊椎动物的祖先，且可能发生在较短的时间段内。高度特化的食鳍者（食鳍脂鲤属、食鳍鱼属和真食鳍脂鲤属）与一种严格的食鱼者（中锯脂鲤属）和一种食无脊椎动物者（小口无齿脂鲤属）有着共同的起源。主要食鱼但兼性食鳍的锯啮脂鲤属与它们并非完全相关。我们的研究结果表明，脂鲤亚目总体食性偏好的转变是罕见事件，很少有逆转或平行现象，并且营养生态的进化转变在目内多样化过程中并未发挥主要作用。这种情况与其他一些类群形成对比，在那些类群中，食性转变在物种多样化中起到了关键作用。
