Deane Andrew
Department of Anatomy and Neurobiology, University of Kentucky, College of Medicine, Lexington, KY 40536-0298, USA.
J Hum Evol. 2009 Mar;56(3):263-74. doi: 10.1016/j.jhevol.2009.01.006. Epub 2009 Feb 26.
Accurately interpreting fossil primate dietary behaviour is necessary to fully understand a species' ecology and connection to its environment. Traditional methods developed to infer diet from hominoid teeth successfully group taxa into broad dietary categories (i.e., folivore, frugivore) but often fail to represent the range of dietary variability characteristic of living apes. This oversimplification is not only a consequence of poor resolution, but may also reflect the use of similar fallback resources by closely related taxa with dissimilar diets. This study demonstrates that additional dietary specificity can be achieved using a morphometric approach to hominoid incisor curvature. High-resolution polynomial curve fitting (HR-PCF) was used to quantify the incisor curvatures of closely related hominoid taxa that have dissimilar diets but similar morphological adaptations to specific keystone resources (e.g., Gorilla gorilla beringei vs. G. g. gorilla). Given the key role of incisors in food processing, it is reasonable to assume that these teeth will be at least partially influenced by the unique selective pressures imposed by the mechanical loading specific to individual diets. Results from this study identify a strong correlation between hominoid dietary proportions and incisor linear dimensions and curvature, indicating that more pronounced incisor curvature is positively correlated with higher levels of frugivory. Hard-object frugivores have the greatest mesiodistal and cervico-incisal curvature and dedicated folivores have the least curved incisors. Mixed folivore/frugivores are morphological intermediates between dedicated folivores and hard- and soft-object frugivores. Mesiodistal curvature varied only in the degree of curvature; however, cervico-incisal curvature was shown to differ qualitatively between more frugivorous and more folivorous taxa. In addition to identifying a greater range of dietary variability among hominoids, this study also demonstrates that HR-PCF is capable of identifying morphological distinctions between closely related taxa with overlapping diets that rely on similar fallback foods (e.g., Pan paniscus vs. P. troglodytes).
准确解读灵长类化石的饮食行为对于全面理解一个物种的生态及其与环境的联系至关重要。为从类人猿牙齿推断饮食而开发的传统方法成功地将分类群归入宽泛的饮食类别（即食叶动物、食果动物），但往往无法体现现存猿类饮食变化的范围。这种过度简化不仅是分辨率低的结果，还可能反映出饮食不同但亲缘关系密切的分类群使用了相似的替代资源。本研究表明，采用形态测量方法研究类人猿门齿曲率可实现更高的饮食特异性。高分辨率多项式曲线拟合（HR - PCF）被用于量化饮食不同但对特定关键资源具有相似形态适应的亲缘关系密切的类人猿分类群的门齿曲率（例如山地大猩猩与西部大猩猩）。鉴于门齿在食物加工中的关键作用，可以合理推测这些牙齿至少会部分受到个体饮食特有的机械负荷所施加的独特选择压力的影响。本研究结果表明，类人猿的饮食比例与门齿线性尺寸及曲率之间存在很强的相关性，这表明更明显的门齿曲率与更高水平的食果性呈正相关。硬食果实类动物的近远中向和颈切向曲率最大，专性食叶动物的门齿曲率最小。食叶/食果混合类动物在形态上介于专性食叶动物与硬食果实和软食果实类动物之间。近远中向曲率仅在弯曲程度上有所不同；然而，颈切向曲率在食果性更强和食叶性更强的分类群之间表现出质的差异。除了识别出类人猿之间更大范围的饮食变异性之外，本研究还表明HR - PCF能够识别饮食重叠但依赖相似替代食物的亲缘关系密切的分类群之间的形态差异（例如倭黑猩猩与黑猩猩）。
