A 3-DIMENSIONALLY BASED MORPHOLOGICAL ANALYSIS OF THE EARLY HOMINID

本计划的目的是利用激光和/或ct扫描获得的数字化整体表面数据集，对古人类倾向进行基于三维的形态学分析。在本研究中，我们开发了一种程序和方法，利用工业微ct扫描仪有效地获得数百个连续ct切片，然后从三维体ct数据中提取精确的表面渲染数据集。我们进一步开发了一个集成的软件系统，可以处理激光和基于ct的数据集，并使用测试对象对体积，表面积，投影面积，弯曲长度进行了全面的精度测试。然后，我们继续使用类似的数字化参数对冠特征进行形态计量学分析。ct系统的使用允许更广泛的比较数据采集，我们收集了32个人类，40个黑猩猩，27个倭黑猩猩，42个猩猩和10个大猩猩臼齿的ct数据集。采用高质量铸型获得53颗早期古人类磨牙的激光扫描三维数据集。这些数据集目前正在分析中，但我们能够在功能上描述早期原始人的第一臼齿状况。南方古猿和早期家臼齿的结构设计是为了在磨损的情况下最大化咬合表面积，并且往往具有较高的牙冠基部，而像潘和蓬戈这样的果食性物种的磨牙是低冠的，咬合中央凹宽。这些特征是共同的健壮和非健壮的物种，尽管在尖面积比例和其他形态两者之间有相当大的差异。

The aim of the present project was to conduct 3-dimensionally based morphological analysis of the hominind bentition by means of using digitized whole surface datasets obtained by laser and/or ct scanning. In the present study, we developed a procedure and method of efficiently obtaining several hundreds of serial ct slices with an industrial micro-ct scanner, then extracting accurate surface rendered datasets from the 3-d volume ct data. We further developed an integrated software system that handles both laser and ct-based datasets, and conducted comprehensive accuracy tests of volume,surface area, projected area, curved lengths using test objects. We then proceeded to conduct morphometric analysis of crown features using similarly digitized parameters. The use of the ct-system allows more versatile comparative data acquisition, and we collected ct datasets of 32 human, 40 chimpanzee, 27 bonobo, 42 orangutan, and 10 gorilla molars. High quality casts were used in obtaining laser-scanned 3D datasets of 53 early hominid molars. These datasets are currently being analyzed, but we were able to characterize functionally the early hominid first molar condition. Whereas the molars of frugivorous species such as Pan and Pongo are low-crowned with broad occlusal fovea, Australopithecus and early Home molars are structurally designed to maximize occlusal surface area in a worn condition and tend to have a tall basal portion of the crown. These characteristics are common to both robust and non-robust species, despite considerable differences between the two in cusp area proportions and other morphologies.