Data from: Correlated evolution of body and fin morphology in the cichlid fishes

Body and fin shape are chief determinants of swimming performance in fishes. Different configurations of body and fin shape can suit different locomotor specializations. The success of any configuration is dependent upon the hydrodynamic interactions between body and fins. Despite the importance of body-fin interactions for swimming, there are few data indicating whether body and fin configurations evolve in concert, or whether these structures vary independently. The cichlid fishes are a diverse family whose well-studied phylogenetic relationships make them ideal for the study of macroevolution of ecomorphology. This study measured body, caudal and median fin morphology from radiographs of 131 cichlid genera, using morphometrics and phylogenetic comparative methods to determine whether these traits exhibit correlated evolution. Partial least squares canonical analysis revealed that body, caudal fin, dorsal fin, and anal fin shapes all exhibited strong correlated evolution consistent with locomotor ecomorphology. Major patterns included the evolution of deep body profiles with long fins, suggestive of maneuvering specialization; and the evolution of narrow, elongate caudal peduncles with concave tails, a combination that characterizes economical cruisers. These results demonstrate that body shape evolution does not occur independently of other traits, but among a suite of other morphological changes that augment locomotor specialization.

鱼类的躯体与鳍的形态，是决定其游泳性能的核心决定因素。躯体与鳍形态的不同组合构型，可适配不同的运动特化需求。任何构型的适配效果，均取决于躯体与鳍之间的流体动力学相互作用。尽管躯体-鳍的相互作用对游泳运动至关重要，但目前鲜有数据能够阐明，躯体与鳍的构型究竟是协同演化，还是各自独立发生变异。慈鲷鱼类（Cichlid fishes）是一类物种多样性极高的类群，其已被广泛研究的系统发育关系使其成为生态形态学宏观演化研究的理想模型。本研究通过形态测量学与系统发育比较分析方法，对131个慈鲷属的X光影像中的躯体、尾鳍及正中鳍形态进行了量化分析，以探究上述性状是否存在协同演化现象。偏最小二乘典范分析（Partial Least Squares Canonical Analysis）结果显示，躯体、尾鳍、背鳍与臀鳍的形态均呈现出与运动生态形态学相符的强协同演化信号。主要演化模式包括：躯体高隆且鳍形修长的类群，该特征指向机动运动特化；以及尾柄窄长且尾鳍呈凹形的类群，该组合特征是高效节能巡航类群的典型标志。本研究结果表明，躯体形态的演化并非独立于其他性状，而是与一系列协同强化运动特化的形态变化共同发生。