Dean M C, Reid D J
Evolutionary Anatomy Unit, Department of Anatomy and Developmental Biology, University College London, London WC1E 6BT, UK.
Am J Phys Anthropol. 2001 Nov;116(3):209-15. doi: 10.1002/ajpa.1116.
We documented the spacing and distribution of perikymata on the buccal enamel surface of fossil hominin anterior teeth with reference to a sample of modern human and modern great ape teeth. A sample of 27 anterior teeth attributed to Australopithecus (5 to A. afarensis, 22 to A. africanus) and of 33 attributed to Paranthropus (6 to P. boisei, and 27 to P. robustus) were replicated and sputter-coated with gold to enable reflected light microscopy of their surface topography. Anterior teeth were then divided into 10 equal divisions of buccal crown height. The total perikymata count in each division of crown height was recorded using a binocular microscope fitted with a vernier micrometer eyepiece. Then the mean number of perikymata per millimeter was calculated for each division. Similar comparative data for a modern sample of 115 unworn human anterior teeth and 30 African great ape anterior teeth were collected from ground sections. Perikymata counts in each taxon (together with either known or presumed periodicities of perikymata) were then used to estimate enamel formation times in each division of crown height, for all anterior tooth types combined. The distributions of these estimates of time taken to form each division of crown height follow the same trends as the actual perikymata counts and differ between taxa in the same basic way. The distinction between modern African great apes and fossil hominins is particularly clear. Finally, we calculated crown formation times for each anterior tooth type by summing cuspal and lateral enamel formation times. Estimates of average crown formation times in australopiths are shorter than those calculated for both modern human and African great ape anterior teeth. The data presented here provide a better basis for exploring differences in perikymata spacing and distribution among fossil hominins, and provide the first opportunity to describe four specimens attributed to Homo in this context. Preliminary data indicate that differences may exist among the species attributed to early Homo, especially between Homo ergaster and Homo rudolfensis on the one hand, and Homo habilis sensu strico on the other.
我们参照现代人类和现代大型猿类牙齿样本，记录了化石人族前牙颊面釉质上釉小皮的间距和分布情况。对27颗归为南方古猿的前牙样本（5颗阿法南方古猿，22颗非洲南方古猿）以及33颗归为傍人属的前牙样本（6颗鲍氏傍人，27颗粗壮傍人）进行复制，并喷镀金膜，以便对其表面形貌进行反射光显微镜观察。然后将前牙的颊冠高度等分为10个部分。使用配备游标测微目镜的双目显微镜记录每个冠高部分的釉小皮总数。接着计算每个部分每毫米的釉小皮平均数量。从磨片上收集了115颗未磨损的现代人类前牙和30颗非洲大型猿类前牙的类似比较数据。然后，将每个分类单元中的釉小皮数量（以及已知或推测的釉小皮周期）用于估算所有前牙类型组合中每个冠高部分的釉质形成时间。这些冠高各部分形成时间估算值的分布趋势与实际釉小皮数量相同，且在不同分类单元之间的差异基本一致。现代非洲大型猿类与化石人族之间的区别尤为明显。最后，我们通过将牙尖和侧面釉质形成时间相加，计算出每种前牙类型的冠形成时间。南方古猿的平均冠形成时间估算值比现代人类和非洲大型猿类前牙的计算值都要短。本文提供的数据为探究化石人族之间釉小皮间距和分布的差异提供了更好的基础，并首次在此背景下描述了4颗归为智人的标本。初步数据表明，早期智人所属物种之间可能存在差异，尤其是一方面匠人智人和鲁道夫人之间，另一方面狭义的能人之间。
