A 3-DIMENSIONALLY BASED MORPHOLOGICAL ANALYSIS OF THE EARLY HOMINID

本项目的目的是通过使用激光和/或ct扫描获得的数字化全表面数据集，对人的边界进行基于三维的形态分析。在本研究中，我们开发了一种使用工业微型CT扫描仪高效地获取数百个连续CT切片，然后从三维体CT数据中提取准确的表面渲染数据集的程序和方法。我们进一步开发了同时处理激光数据集和基于CT的数据集的集成软件系统，并使用测试对象对体积、表面积、投影面积、曲线长度进行了全面的精度测试。然后，我们使用类似的数字化参数对树冠特征进行形态计量分析。使用ct系统可以获得更多用途的比较数据，我们收集了32个人类、40个黑猩猩、27个矮黑猩猩、42个猩猩和10个大猩猩磨牙的ct数据集。使用高质量的铸型获得了53颗早期人类磨牙的激光扫描3D数据集。这些数据集目前正在分析中，但我们能够从功能上描述早期人类第一磨牙的状况。而像潘和庞戈这样的食果性物种的磨牙是低冠的，具有宽阔的咬合凹陷，而南方古猿和早期家庭磨牙的结构设计是为了在磨损的条件下最大限度地扩大咬合表面积，并且往往有一个很高的牙冠底部。这些特征对健壮和不健壮的物种都是共同的，尽管两者在尖端面积比例和其他形态上有相当大的差异。

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.