Durham University, Department of Anthropology, South Road, Durham, DH1 3LE, UK; Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 040103, Leipzig, Germany.
Department of Anthropology and Neukom Institute for Computational Science, Dartmouth, 6047 Silsby Hall, Hanover, NH 03755, USA.
J Hum Evol. 2017 Nov;112:15-29. doi: 10.1016/j.jhevol.2017.09.001. Epub 2017 Sep 29.
Dental topography reflects diet accurately in several extant and extinct mammalian clades. However, dental topographic dietary reconstructions have high success rates only when closely related taxa are compared. Given the dietary breadth that exists among extant apes and likely existed among fossil hominins, dental topographic values from many species and subspecies of great apes are necessary for making dietary inferences about the hominin fossil record. Here, we present the results of one metric of dental topography, Dirichlet normal energy (DNE), for seven groups of great apes (Pongo pygmaeus pygmaeus, Pan paniscus, Pan troglodytes troglodytes and schweinfurthii, Gorilla gorilla gorilla, Gorilla beringei graueri and beringei). Dirichlet normal energy was inadequate at differentiating folivores from frugivores, but was adequate at predicting which groups had more fibrous diets among sympatric African apes. Character displacement analyses confirmed there is substantial dental topographic and relative molar size (M:M ratio; length, width, and area) divergence in sympatric apes when compared to their allopatric counterparts, but character displacement is only present in relative molar size when DNE is also considered. Presence of character displacement is likely due to indirect competition over similar food resources. Assuming similar ecological conditions in the Plio-Pleistocene, the derived masticatory apparatuses of the robust australopiths and early Homo may be due to indirect competition over dietary resources between the taxa, causing dietary niche partitioning. Our results imply that dental topography cannot be used to predict dietary categories in fossil hominins without consideration of ecological factors, such as dietary and geographic overlap. In addition, our results may open new avenues for understanding the community compositions of early hominins and the formation of specific ecological niches among hominin taxa.
牙表面形态学在几个现存和已灭绝的哺乳动物类群中能准确反映饮食情况。然而，只有在密切相关的分类单元进行比较时，牙表面形态学的饮食重建才具有较高的成功率。鉴于现生类人猿之间存在的饮食广度，以及化石人科动物可能存在的饮食广度，需要有许多大型猿类物种和亚种的牙表面形态学数据，才能对人科化石记录进行饮食推断。在这里，我们提供了七种大型猿类（倭黑猩猩指名亚种、黑猩猩、大猩猩指名亚种、大猩猩东非亚种、大猩猩西部低地亚种和大猩猩山地亚种）的牙表面形态学度量之一 Dirichlet 正态能量（DNE）的结果。DNE 不足以区分食叶动物和食果动物，但足以预测哪些群体在非洲同域生活的猿类中具有更多纤维性饮食。特征离散分析证实，与异地生活的同类相比，同域生活的猿类在牙表面形态学和相对磨牙大小（M：M 比值；长度、宽度和面积）上存在很大差异，但当同时考虑 DNE 时，只有相对磨牙大小上存在特征离散。特征离散的出现可能是由于对相似食物资源的间接竞争。假设上新世-更新世期间的生态条件相似，粗壮南方古猿和早期人类衍生的咀嚼器官可能是由于分类群之间对饮食资源的间接竞争，导致饮食生态位分化。我们的研究结果表明，在不考虑生态因素（如饮食和地理重叠）的情况下，牙表面形态学不能用于预测化石人科动物的饮食类别。此外，我们的研究结果可能为理解早期人科动物的群落组成以及人科动物分类群中特定生态位的形成开辟新途径。
