Center for the Study of Human Origins, Department of Anthropology, New York University, New York, NY 10003, USA.
J Hum Evol. 2011 Nov;61(5):564-74. doi: 10.1016/j.jhevol.2011.07.005. Epub 2011 Aug 27.
Several well-known Miocene catarrhines, including Proconsul heseloni, have been inferred to combine quadrupedal walking in an arboreal substrate with a significant amount of climbing during locomotion. The degree to which some of these species were adapted to perform these behaviors is not fully understood due to the mosaic of 'ape-like' and 'monkey-like' traits identified in the forelimb. Given these unique combinations of forelimb features in the fossils, we report on forelimb traits that should be emphasized when investigating skeletal adaptation to quadrupedalism (defined in this manuscript as symmetrical gait movement on horizontal supports, excluding knuckle-walking) and climbing (including both vertical climbing and clambering). We investigate the correspondence between: 1) quadrupedalism and two well-known forelimb traits, humeral torsion and olecranon process length, and 2) climbing and phalangeal curvature. We also test the degree of phylogenetic signal in these relationships using phylogenetic generalized least-squares and branch length transformation methods in order to determine the models of best-fit. We present models that can be used to predict proportions of quadrupedalism and climbing in extant and extinct anthropoid taxa. Each trait-behavior correlation is significant and characterized by an absence of phylogenetic signal. Thus, we employ models assuming a star phylogeny to predict locomotor proportions. The climbing model based on phalangeal curvature and a proxy for size provides the most accurate predictions of behavior across anthropoids. The two quadrupedalism models are less accurate, but distinguish highly quadrupedal species from those that are not. Predictive equations based on these traits support the inference that P. heseloni performed a high proportion of quadrupedalism with a significant climbing component. The degree of phalangeal curvature measured in Pliopithecus vindobonensis predicts that this Miocene catarrhine species performed a proportion of climbing similar to Proconsul, while humeral torsion and olecranon process length provide conflicting inferences of quadrupedal locomotion in this species.
几种著名的中新世大型猫科动物，包括原康修尔猿，被推断为在树栖环境中采用四足行走方式，同时在运动过程中进行大量攀爬。由于在前肢中发现了一些“似猿”和“似猴”的特征，这些物种在多大程度上适应了这些行为尚不完全清楚。鉴于这些化石中前肢特征的独特组合，我们报告了在研究骨骼对四足行走（本文中定义为在水平支撑物上进行对称步态运动，不包括指节行走）和攀爬（包括垂直攀爬和攀爬）的适应性时应强调的前肢特征。我们研究了以下两个方面之间的对应关系：1）四足行走与两个著名的前肢特征，肱骨扭转和尺骨鹰嘴长度，以及 2）攀爬与指骨曲率。我们还使用分支长度转换方法和分支长度转换方法测试了这些关系中的系统发育信号程度，以确定最佳拟合模型。我们提出了可以用于预测现生和已灭绝的类人猿类群中四足行走和攀爬比例的模型。每个特征-行为相关性都很显著，并且没有系统发育信号的特征。因此，我们采用了假设星状系统发育的模型来预测运动比例。基于指骨曲率和大小替代物的攀爬模型提供了在类人猿中最准确的行为预测。两个四足行走模型的准确性较低，但可以区分高度四足行走的物种和非四足行走的物种。基于这些特征的预测方程支持了这样的推断，即 P. heseloni 采用了高度四足行走的方式，并具有重要的攀爬成分。在 Pliopithecus vindobonensis 中测量的指骨曲率程度预测，这个中新世大型猫科动物进行了类似于原康修尔猿的攀爬比例，而肱骨扭转和尺骨鹰嘴长度则提供了该物种四足运动的相互矛盾的推断。
