McCollum Melanie A
Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22908-0732, USA.
J Hum Evol. 2008 Jan;54(1):2-14. doi: 10.1016/j.jhevol.2007.05.013. Epub 2007 Sep 10.
In a previous study of the patterns of facial growth remodeling characteristic of early hominid taxa, Bromage (1989) demonstrated that the nasoalveolar clivus of A. robustus was resorptive throughout ontogeny. Based upon the remodeling information provided by small samples (n=6 each) of chimpanzees and modern humans, he concluded that the clival resorption pattern characteristic of robust Australopithecus differed significantly from that of chimpanzees and was instead somewhat convergent upon that of modern humans, in that it served to emphasize a downward facial growth vector. The present study used the SEM/replica technique to assess nasomaxillary remodeling in larger, more age-varied samples of chimpanzee (n=33) and modern human crania (n=22). Results indicate far more intraspecific variability in nasomaxillary remodeling than suggested by Bromage's earlier study. In particular, results from an expanded sample demonstrate that the nasoalveolar clivus of chimpanzees is frequently resorptive, especially at later stages of ontogeny. However, the pattern of clival remodeling observed in chimpanzees is unlike that typical of robust Australopithecus, in which clival resorption occurs throughout ontogeny and in expansive fields that cover the entire clival surface. Although Bromage (1989) considered the pattern of nasomaxillary remodeling observed in robust Australopithecus to have been a byproduct of an extreme maxillary growth rotation, the failure of A. africanus to display a similar pattern suggests that some other factor(s) may have been involved. Regardless, it is unlikely that clival resorption in robust Australopithecus would have significantly impacted the overall vector of facial growth. Instead, the primary morphogenetic effect of this pattern of clival resorption would have been one of local surface sculpting.
在之前一项关于早期人科动物类群面部生长重塑模式特征的研究中，布罗梅奇（1989年）证明，粗壮傍人整个个体发育过程中鼻牙槽斜面都在发生吸收。基于对黑猩猩和现代人的小样本（每组n = 6）所提供的重塑信息，他得出结论，粗壮南方古猿特有的斜面吸收模式与黑猩猩的显著不同，反而在某种程度上与现代人的模式趋同，因为它有助于强调面部向下的生长向量。本研究使用扫描电子显微镜/复型技术，对更大且年龄分布更广的黑猩猩样本（n = 33）和现代人类颅骨样本（n = 22）的鼻上颌重塑情况进行评估。结果表明，鼻上颌重塑的种内变异性比布罗梅奇早期研究所显示的要大得多。特别是，来自扩大样本的结果表明，黑猩猩的鼻牙槽斜面经常发生吸收，尤其是在个体发育的后期阶段。然而，在黑猩猩中观察到的斜面重塑模式与粗壮南方古猿典型的模式不同，粗壮南方古猿的斜面吸收在整个个体发育过程中都有发生，且发生在覆盖整个斜面表面的广阔区域。尽管布罗梅奇（1989年）认为在粗壮南方古猿中观察到的鼻上颌重塑模式是极端上颌生长旋转的副产品，但非洲南方古猿未表现出类似模式这一情况表明，可能涉及其他一些因素。无论如何，粗壮南方古猿的斜面吸收不太可能对面部生长的总体向量产生显著影响。相反，这种斜面吸收模式的主要形态发生作用可能是局部表面塑形。
