Data from: Common evolutionary trends underlie the four-bar linkage systems of sunfish and mantis shrimp

Comparative biomechanics offers an opportunity to explore the evolution of
disparate biological systems that share common underlying mechanics.
Four-bar linkage modelling has been applied to various biological systems
such as fish jaws and crustacean appendages to explore the relationship
between biomechanics and evolutionary diversification. Mechanical
sensitivity states that the functional output of a mechanical system will
show differential sensitivity to changes in specific morphological
components. We document similar patterns of mechanical sensitivity in two
disparate four-bar systems from different phyla: the opercular four-bar
system in centrarchid fishes and the raptorial appendage of stomatopods.
We built dynamic linkage models of 20 centrarchid and 36 stomatopod
species and used phylogenetic generalized least squares regression (PGLS)
to compare evolutionary shifts in linkage morphology and mechanical
outputs derived from the models. In both systems, the kinematics of the
four-bar mechanism show significant evolutionary correlation with the
output link, while travel distance of the output arm is correlated with
the coupler link. This common evolutionary pattern seen in both fish and
crustacean taxa is a potential consequence of the mechanical principles
underlying four-bar systems. Our results illustrate the potential
influence of physical principles on morphological evolution across
biological systems with different structures, behaviors and ecologies.

比较生物力学（comparative biomechanics）为探究拥有共同底层力学机制的不同生物类群的演化提供了重要契机。四连杆机构建模已被应用于鱼类颌部、甲壳类附肢等多种生物系统，以探究生物力学与演化分化之间的关联。机械灵敏度原理指出，机械系统的功能输出会对特定形态组分的变化表现出差异化的灵敏度。我们在两个来自不同门类的异源四连杆系统中记录到了相似的机械灵敏度模式：日鲈科（centrarchid）鱼类的鳃盖四连杆系统，以及口足类（stomatopods）的掠食性附肢。我们构建了20种日鲈科鱼类和36种口足类的动态连杆模型，并采用系统发育广义最小二乘回归（phylogenetic generalized least squares regression, PGLS）对比连杆形态与模型导出的力学输出的演化变化。在两个系统中，四连杆机构的运动学特征均与输出连杆存在显著的演化相关性，而输出臂的行程距离则与耦合连杆相关联。鱼类与甲壳类类群共有的这一演化模式，可能是四连杆系统底层力学原理作用的结果。我们的研究结果表明，物理原理可对具有不同结构、行为与生态特征的各类生物系统的形态演化产生潜在影响。