Wood B A, Abbott S A, Graham S H
J Anat. 1983 Sep;137 (Pt 2)(Pt 2):287-314.
Accurate measurements of the absolute and relative size of individual cusps, the arrangement of the primary fissure system and the shape of coronal cross sections of the tooth crown have been used to investigate the pattern of variation in Plio-Pleistocene hominid mandibular molar teeth. Teeth were either grouped into one of six taxonomic categories or considered as individual cases. Univariate analysis of relative cusp areas shows that the two taxonomic categories of 'robust' hominids from East and Southern Africa have relatively small mesial cusps, but a relatively large entoconid and hypoconulid and Principal Component plots of the data show that the 'robust' categories can be distinguished on the basis of relative cusp size. Other evidence suggests that these differences are not likely to be the result of allometric phenomena. Fissure pattern was analysed using the X/Y coordinates of defined reference points. Patterns were compared by Procrustes analysis and the relationships between teeth contained in the resulting similarity matrix were portrayed using Principal Coordinates plots and a nearest neighbours table. The positions of the posterior fovea and the mesial longitudinal fissure were important for distinguishing taxonomic categories. The shape of the coronal profiles proved difficult to quantify, but there were consistent and distinct differences between the South African 'robust' sample and teeth included within the East African Homo category. When these results are combined with those of a previous study of overall crown size and the distribution of extra cusps, they allow the affinities of isolated teeth or contentious specimens to be assessed. For example, our results show that KNM-ER 1506 and 1802 are more similar to the East African Homo group than any other category, and they indicate that though SK 1587 and 1588 are small teeth, they nonetheless are closest to the South African 'robust' category in terms of relative cusp size, fissure pattern and crown profile shape. The closest affinities of the Taung First mandibular molars are also with the South African 'robust' sample.
对单个牙尖的绝对大小和相对大小、主要裂沟系统的排列以及牙冠冠状横截面的形状进行精确测量，已被用于研究上新世-更新世人类下颌磨牙的变异模式。牙齿要么被归入六个分类类别之一，要么被视为个体案例。对相对牙尖面积的单变量分析表明，来自东非和南非的“粗壮型”人类的两个分类类别具有相对较小的近中牙尖，但具有相对较大的下内尖和下后尖，数据的主成分图显示，“粗壮型”类别可以根据相对牙尖大小来区分。其他证据表明，这些差异不太可能是异速生长现象的结果。使用定义的参考点的X/Y坐标分析裂沟模式。通过普氏分析比较模式，并使用主坐标图和最近邻表描绘所得相似性矩阵中包含的牙齿之间的关系。后小凹和近中纵裂的位置对于区分分类类别很重要。冠状轮廓的形状难以量化，但南非“粗壮型”样本与东非智人类别中的牙齿之间存在一致且明显的差异。当这些结果与先前关于整体牙冠大小和额外牙尖分布的研究结果相结合时，它们可以评估孤立牙齿或有争议标本的亲缘关系。例如，我们的结果表明，KNM-ER 1506和1802与东非智人群体比与任何其他类别更相似，并且它们表明，尽管SK 1587和1588是小牙齿，但就相对牙尖大小、裂沟模式和牙冠轮廓形状而言，它们最接近南非“粗壮型”类别。汤恩第一下颌磨牙的最亲近亲缘关系也与南非“粗壮型”样本有关。
