Guatelli-Steinberg Debbie
Department of Anthropology, Ohio State University, Newark, Ohio 43055, USA.
Am J Phys Anthropol. 2004 Mar;123(3):199-215. doi: 10.1002/ajpa.10324.
This study of linear enamel hypoplasia (LEH) in Plio-Pleistocene hominins builds on a previous study (Guatelli-Steinberg [2003] Am. J. Phys. Anthropol. 120:309-322) that focused on LEH in early South African hominins. The present study is more comprehensive, encompassing dental specimens of hominins from East Africa as well, including early Homo. As a developmental defect of enamel, LEH is used in anthropological contexts to reveal information about physiological stress. However, intrinsic aspects of enamel development and morphology can affect the expression of LEH, complicating efforts to understand the significance of these defects. In this study, the analysis of LEH is conducted with respect to enamel development and morphology. It is predicted that Paranthropus should have fewer defects on its canine teeth than Australopithecus and Homo, owing to its abbreviated period of enamel formation. This prediction is supported: Paranthropus has statistically significantly fewer defects per canine than Australopithecus and Homo. The previous study demonstrated that despite the wider spacing of perikymata on the teeth of South African Paranthropus, defects on the canine teeth of this genus were not wider than those of Australopithecus. A multiple linear regression analysis in that study, as well as a separate analysis in the present study, indicate that the number of perikymata within defects is a better predictor of defect width than perikymata spacing. In this study, it was additionally found that the average number of perikymata within Australopithecus defects is statistically significantly greater than it is in Paranthropus, thus explaining why Paranthropus defects are not wider than those of Australopithecus. The biological significance of this difference in the number of perikymata within the defects of Australopithecus and Paranthropus is considered in light of several factors, including: 1) the possibility that other intrinsic attributes of enamel morphology may be involved (specifically the faster extension rates of Paranthropus that result in shallower defects), 2) generic differences in the canalization of enamel development, and 3) generic differences in the duration of disruptions to enamel growth.
这项关于上新世 - 更新世古人类线性釉质发育不全（LEH）的研究建立在之前一项研究（瓜泰利 - 斯坦伯格[2003]《美国体质人类学杂志》120:309 - 322）的基础之上，该研究聚焦于南非早期古人类的LEH。本研究更为全面，涵盖了来自东非古人类的牙齿标本，包括早期智人。作为釉质发育缺陷，LEH在人类学背景下被用于揭示有关生理压力的信息。然而，釉质发育和形态的内在方面会影响LEH的表现，使得理解这些缺陷的意义变得复杂。在本研究中，对LEH的分析是针对釉质发育和形态进行的。据预测，傍人属犬齿上的缺陷应比南方古猿属和人属更少，这是由于其釉质形成期较短。这一预测得到了支持：傍人属每颗犬齿上的缺陷在统计学上显著少于南方古猿属和人属。之前的研究表明，尽管南非傍人牙齿上的釉质横纹间距更宽，但该属犬齿上的缺陷并不比南方古猿属的宽。该研究中的多元线性回归分析以及本研究中的一项单独分析表明，缺陷内釉质横纹的数量比釉质横纹间距更能预测缺陷宽度。在本研究中还发现，南方古猿属缺陷内釉质横纹的平均数量在统计学上显著多于傍人属，这就解释了为什么傍人属的缺陷不比南方古猿属的宽。结合几个因素来考虑南方古猿属和傍人属缺陷内釉质横纹数量差异的生物学意义，这些因素包括：1）釉质形态的其他内在属性可能参与其中的可能性（特别是傍人属更快的延伸速率导致更浅的缺陷），2）釉质发育定向化的属间差异，以及3）釉质生长中断持续时间的属间差异。
