Konrad Lorenz Institute for Evolution and Cognition Research, Altenberg, Austria.
Evolution. 2012 Apr;66(4):1024-43. doi: 10.1111/j.1558-5646.2011.01508.x. Epub 2012 Jan 5.
As the most common and best preserved remains in the fossil record, teeth are central to our understanding of evolution. However, many evolutionary analyses based on dental traits overlook the constraints that limit dental evolution. These constraints are diverse, ranging from developmental interactions between the individual elements of a homologous series (the whole dentition) to functional constraints related to occlusion. This study evaluates morphological integration in the hominin dentition and its effect on dental evolution in an extensive sample of Plio- and Pleistocene hominin teeth using geometric morphometrics and phylogenetic comparative methods. Results reveal that premolars and molars display significant levels of covariation; that integration is stronger in the mandibular dentition than in the maxillary dentition; and that antagonist teeth, especially first molars, are strongly integrated. Results also show an association of morphological integration and evolution. Stasis is observed in elements with strong functional and/or developmental interactions, namely in first molars. Alternatively, directional evolution (and weaker integration) occurs in the elements with marginal roles in occlusion and mastication, probably in response to other direct or indirect selective pressures. This study points to the need to reevaluate hypotheses about hominin evolution based on dental characters, given the complex scenario in which teeth evolve.
作为化石记录中最常见和保存最完好的遗骸，牙齿是我们理解进化的核心。然而，许多基于牙齿特征的进化分析都忽略了限制牙齿进化的约束。这些约束是多种多样的，从同源系列（整个牙列）个体元素之间的发育相互作用到与咬合相关的功能约束。本研究使用几何形态测量学和系统发育比较方法，在广泛的上新世和更新世人类牙齿样本中评估了人属牙齿的形态整合及其对牙齿进化的影响。结果表明，前磨牙和磨牙表现出显著的共变；下颌牙列的整合比上颌牙列更强；拮抗牙，特别是第一磨牙，具有很强的整合性。结果还表明形态整合与进化之间存在关联。在具有强烈功能和/或发育相互作用的元素中观察到稳定，即在第一磨牙中。相反，在咬合和咀嚼作用中作用较小的元素中发生定向进化（整合性较弱），这可能是对其他直接或间接选择压力的反应。这项研究表明，鉴于牙齿进化的复杂情况，需要重新评估基于牙齿特征的人类进化假说。
