Center for Advanced Study of Human Paleobiology, Department of Anthropology, George Washington University, Washington, DC 20052, USA.
Division of Anthropology, American Museum of Natural History, New York, NY 10024, USA; Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Edifici ICTA-ICP, c/ Columnes s/n, Campus de la UAB, Cerdanyola del Vallès, Barcelona, 08193, Spain; New York Consortium in Evolutionary Primatology (NYCEP), USA.
J Hum Evol. 2019 Dec;137:102684. doi: 10.1016/j.jhevol.2019.102684. Epub 2019 Oct 24.
Gorillas occupy habitats that range in elevation from 0 to 3850 m. Populations at higher elevations tend to be less arboreal than lowland populations. Variation in habitat-specific behaviors among closely related populations makes gorillas a unique model to study the relationship between locomotion and morphology. The pelvis reflects differences in locomotion in other primates, and thus may also reflect locomotor differences among gorillas. We tested the hypothesis that pelvic morphology exhibits clinal variation across elevation within Gorilla. Using 3D geometric morphometrics and principal components analysis (PCA), we characterized pelvic shape in three gorilla subspecies representing 14 localities across gorillas' full elevation range: western lowland gorillas (Gorilla gorilla gorilla), mountain gorillas (Gorilla beringei beringei), and Grauer's gorillas (Gorilla beringei graueri). We found that the first principal component (PC1) usually reflects differences between western and eastern gorillas in the lateral margin of the ilium and, in males, the obturator foramen. When sexes are considered together, the second principal component (PC2) indicates some separation between G. b. beringei and G. b. graueri, albeit with considerable overlap, corresponding to the shape of the iliac crest. When sexes were analyzed separately, there was no distinction. Phylogenetic generalized least squares regression was used to evaluate the relationship between elevation and pelvic shape under varying phylogenetic assumptions. Models were compared to assess how phylogenetic adjustment affects model fit. Neither of the first two PCs nor overall shape yielded a significant relationship with elevation in any of the pooled-sex and individual-sex samples. This suggests that covariation between pelvic morphology and elevation is sex-specific and dependent on phylogenetic assumptions. Our results find complex interactions between sex, phylogeny, elevation, and pelvic morphology, suggesting that there is not one ecomorphological pattern that characterizes all gorillas.
大猩猩栖息的海拔范围从 0 到 3850 米不等。高海拔地区的种群往往比低地种群的树栖性差。在密切相关的种群中，特定栖息地行为的变化使大猩猩成为研究运动和形态之间关系的独特模型。骨盆反映了其他灵长类动物在运动方面的差异，因此也可能反映了大猩猩之间运动能力的差异。我们检验了这样一个假设，即在大猩猩内部，骨盆形态在海拔范围内表现出渐变的假设。我们使用 3D 几何形态测量学和主成分分析（PCA），在代表大猩猩整个海拔范围的 14 个地点的三个大猩猩亚种中，描述了骨盆的形状：西部低地大猩猩（Gorilla gorilla gorilla）、山地大猩猩（Gorilla beringei beringei）和格氏大猩猩（Gorilla beringei graueri）。我们发现，第一主成分（PC1）通常反映了髂骨外侧缘和雄性闭孔的西部大猩猩和东部大猩猩之间的差异。当考虑到性别时，第二主成分（PC2）表明 G. b. beringei 和 G. b. graueri 之间存在一些分离，尽管存在相当大的重叠，这与髂嵴的形状相对应。当性别分别进行分析时，没有区别。系统发育广义最小二乘回归用于评估在不同系统发育假设下，海拔与骨盆形态之间的关系。比较了模型，以评估系统发育调整如何影响模型拟合。在任何 pooled-sex 和 individual-sex 样本中，第一和第二主成分或整体形状都与海拔没有显著关系。这表明，骨盆形态与海拔之间的共变是性别特异性的，并取决于系统发育假设。我们的研究结果发现，性别、系统发育、海拔和骨盆形态之间存在复杂的相互作用，这表明没有一种生态形态模式可以概括所有大猩猩。
