The evolution of locomotor rhythmicity in tetrapods

Differences in rhythmicity (relative variance in cycle period) between mammal, fish, and lizard feeding systems have been hypothesized to be associated with differences in their sensorimotor control systems. We tested this hypothesis by examining whether the locomotion of tachymetabolic tetrapods (birds and mammals) is more rhythmic than that of bradymetabolic tetrapods (lizards, alligators, turtles, salamanders). Species averages of intra-individual coefficients of variation in cycle period were compared while controlling for gait and substrate. Variance in locomotor cycle periods is significantly lower in tachymetabolic than in bradymetabolic animals for data sets that include treadmill locomotion, non-treadmill locomotion, or both. When phylogenetic relationships are taken into account, the non-treadmill analysis and the pooled analyses remain significant, the treadmill analysis becomes nonsignificant (but only marginally). The co-occurrence of relatively high rhythmicity in both fee...

哺乳类、鱼类与蜥蜴取食系统的节律性（周期相对变异度）差异，曾被假说认为与其各自的感觉运动控制系统差异存在关联。本研究通过检验快代谢四足类（tachymetabolic tetrapods，鸟类与哺乳类）的运动是否比慢代谢四足类（bradymetabolic tetrapods，蜥蜴、短吻鳄、龟类、蝾螈）更具节律性，对该假说展开验证。在控制步态与运动基质的前提下，我们比较了个体内周期变异系数的物种平均值。结果显示，在涵盖跑步机运动、非跑步机运动或二者兼具的数据集当中，快代谢类群的运动周期变异度显著低于慢代谢类群。当纳入系统发育关系进行分析时，非跑步机运动分析与合并分析仍保持统计学显著性，而跑步机运动分析则不再显著（仅呈边际显著性）。两类群兼具较高节律性的共现现象在……