Convergent evolution of locomotor morphology but not performance in gymnotiform swimmers

Convergent evolution of a novel locomotor strategy implies that a fitness benefit may be associated with the new gait. Opportunities to study this phenomenon are often constrained by a lack of transitional taxa, but teleost fishes offer examples of extant species across such evolutionary shifts in gait. For instance, one species from Osteoglossiformes and the entire order of Gymnotiformes independently evolved a novel gait, gymnotiform locomotion, where thrust is produced by the undulation of an elongate anal fin. Here, we investigate whether this convergence in gait is also associated with similarities in shape, burst swimming abilities, and/or steady‐swimming energetics. Specifically, we measured body and fin morphology of fish within Gymnotiformes and Osteoglossiformes, along with closely related Siluriformes and Cypriniformes, to examine the link between gymnotiform locomotion and morphology in a phylogenetic context. Second, we tested the burst swimming capabilities and oxygen cons...

一种新型运动策略的趋同进化表明，这种新步态可能与适合度优势相关。研究这一现象的机会往往因缺乏过渡类群而受限，但真骨鱼类（teleost fishes）提供了跨越步态进化转变的现存物种实例。例如，骨舌鱼目（Osteoglossiformes）中的一个物种与全裸背电鳗目（Gymnotiformes）独立演化出一种新型步态——裸背电鳗式运动（gymnotiform locomotion），其推力由延长的臀鳍波动产生。本研究旨在探究这种步态趋同是否也与形态、爆发游泳能力及/或稳定游泳能量学特征的相似性相关。具体而言，我们测量了裸背电鳗目、骨舌鱼目鱼类及其近缘类群鲇形目（Siluriformes）和鲤形目（Cypriniformes）的身体与鳍形态，以在系统发育背景下探讨裸背电鳗式运动与形态之间的关联。其次，我们测试了爆发游泳能力及氧气消...