Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany.
J Hum Evol. 2010 Nov;59(5):525-41. doi: 10.1016/j.jhevol.2010.05.009. Epub 2010 Aug 16.
Neanderthals have a distinctive suite of dental features, including large anterior crown and root dimensions and molars with enlarged pulp cavities. Yet, there is little known about variation in molar root morphology in Neanderthals and other recent and fossil members of Homo. Here, we provide the first comprehensive metric analysis of permanent mandibular molar root morphology in Middle and Late Pleistocene Homo neanderthalensis, and Late Pleistocene (Aterian) and recent Homo sapiens. We specifically address the question of whether root form can be used to distinguish between these groups and assess whether any variation in root form can be related to differences in tooth function. We apply a microtomographic imaging approach to visualise and quantify the external and internal dental morphologies of both isolated molars and molars embedded in the mandible (n=127). Univariate and multivariate analyses reveal both similarities (root length and pulp volume) and differences (occurrence of pyramidal roots and dental tissue volume proportion) in molar root morphology among penecontemporaneous Neanderthals and Aterian H. sapiens. In contrast, the molars of recent H. sapiens are markedly smaller than both Pleistocene H. sapiens and Neanderthals, but share with the former the dentine volume reduction and a smaller root-to-crown volume compared with Neanderthals. Furthermore, we found the first molar to have the largest average root surface area in recent H. sapiens and Neanderthals, although in the latter the difference between M(1) and M(2) is small. In contrast, Aterian H. sapiens root surface areas peak at M(2). Since root surface area is linked to masticatory function, this suggests a distinct occlusal loading regime in Neanderthals compared with both recent and Pleistocene H. sapiens.
尼安德特人具有独特的一系列牙齿特征，包括较大的前冠和根尺寸以及具有扩大的牙髓腔的臼齿。然而，关于尼安德特人和其他现代和化石人类的臼齿根形态的变异知之甚少。在这里，我们提供了对中更新世尼安德特人和晚更新世（阿替林期）和现代智人下颌恒磨牙根形态的首次全面度量分析。我们特别解决了根形态是否可用于区分这些群体的问题，并评估根形态的任何变化是否与牙齿功能的差异有关。我们应用微断层扫描成像方法来可视化和量化孤立臼齿和嵌入下颌骨中的臼齿的外部和内部牙齿形态（n=127）。单变量和多变量分析揭示了同时代的尼安德特人和阿替林期智人之间的臼齿根形态的相似性（根长和牙髓体积）和差异（金字塔根的出现和牙本质组织体积比例）。相比之下，现代人的臼齿明显小于更新世的智人和尼安德特人，但与前者一样，与尼安德特人相比，牙本质体积减少，根冠体积较小。此外，我们发现第一磨牙在现代人中和尼安德特人中具有最大的平均根表面积，尽管在后者中 M(1)和 M(2)之间的差异很小。相比之下，阿替林期智人的根表面积在 M(2)处达到峰值。由于根表面积与咀嚼功能有关，这表明与现代人和更新世智人相比，尼安德特人具有明显不同的咬合加载模式。
