Asymmetrical gait kinematics of free-ranging callitrichine primates in response to changes in substrate diameter and orientation
Asymmetrical gait kinematics of free-ranging callitrichine primates in response to changes in substrate diameter and orientation
复制标题
DOI：
10.1242/jeb.217562
复制
发表时间：
2020-06-01
影响因子：
2.8
通讯作者：
Young, Jesse W.
中科院分区：
文献类型：
--
作者：
Dunham, Noah T.;McNamara, Allison;Young, Jesse W.
树木环境对动物在不同直径、方向和顺应性的基质中移动和觅食提出了相当大的生物力学挑战。灵长类动物和其他树栖哺乳动物的四足步态运动学研究大多集中在对称行走步态和对角序列步态的意义上。相当少的研究已经检查了不对称的步态，尽管他们普遍存在于小体树木分类群。在这里，我们研究了自由放养的灵长类动物是否以及如何调整不对称的步态运动学以适应基底直径和方向的变化，以及步态运动学的变化如何影响基底位移。我们使用高速视频拍摄了生活在厄瓜多尔蒂普蒂尼生物多样性站的自由放养的三趾沙蜥和小鳞山蜥。研究发现，三头棘猴在较大的基质上采用边界和半边界步态，而在较小的基质上采用跑动和对称步态，并且还改变了与从动物传递到基质的衰减力相一致的几个运动学参数。同样，C. pygmaea在较大的基质上从高冲击边界步态转向在较小的基质上使用更多的半边界步态；然而，对基材直径的运动学调整不像S. Mpartitus那样深刻。两种动物都调整步态运动学以适应基底方向的变化；然而，步态运动学并没有显著影响两种动物基底位移的经验测量。因为它们体型小。爪状的指甲和较弱的抓握能力，可以说是灵长类动物进化早期现存的生物力学类似物。因此，更多的注意力应该放在理解不对称的步态动力学，以洞察关于早期灵长类动物运动进化的假设。
Arboreal environments present considerable biomechanical challenges for animals moving and foraging among substrates varying in diameter, orientation and compliance. Most studies of quadrupedal gait kinematics in primates and other arboreal mammals have focused on symmetrical walking gaits and the significance of diagonal sequence gaits. Considerably less research has examined asymmetrical gaits, despite their prevalence in small-bodied arboreal taxa. Here, we examined whether and how free-ranging callitrichine primates adjust asymmetrical gait kinematics to changes in substrate diameter and orientation, as well as how variation in gait kinematics affects substrate displacement. We used high-speed video to film free-ranging Saguinus tripartitus and Cebuella pygmaea inhabiting the Tiputini Biodiversity Station, Ecuador. We found that S. tripartitus used bounding and half-bounding gaits on larger substrates versus gallops and symmetrical gaits on smaller substrates, and also shifted several kinematic parameters consistent with attenuating forces transferred from the animal to the substrate. Similarly, C. pygmaea shifted from high-impact bounding gaits on larger substrates to using more half-bounding gaits on smaller substrates; however, kinematic adjustments to substrate diameter were not as profound as in S. Mpartitus. Both species adjusted gait kinematics to changes in substrate orientation; however, gait kinematics did not significantly affect empirical measures of substrate displacement in either species. Because of their small body size. claw-like nails and reduced grasping capabilities, callitrichines arguably represent extant biomechanical analogs for an early stage in primate evolution. As such, greater attention should be placed on understanding asymmetrical gait dynamics for insight into hypotheses concerning early primate locomotor evolution.