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采用形态观察和几何形态测量方法对周口店直立人,以及南方古猿、非洲早期人属、亚洲其他地区直立人、欧洲更新世人类、现代中国人下颌前臼齿(P3,72枚;P4,69枚)进行了对比分析,结果显示人类下前臼齿齿冠咬合面形态结构及轮廓形状具有明显的演化变化.南方古猿下前臼齿齿冠轮廓不对称,颊侧近、远中垂直沟明显;P3咬合面前凹开裂,跟座较大;P4齿冠颊侧近、远中垂直沟明显;出现“H”型齿沟.这些特征在后期化石人类中有不同程度的体现,但呈减弱趋势.现代人P3和P4齿冠轮廓基本对称;齿冠颊侧近、远中垂直沟已经消失或微弱;跟座缩小.本研究发现周口店直立人下前臼齿保留了许多早期人类的原始特征,包括齿冠舌侧不对称、明显的颊侧近、远中垂直沟等.此外,周口店直立人P3和P4齿冠形态存在明显的内部变异,主要包括程度不同的颊侧近、远中垂直沟、轮廓对称性、齿尖区相对于外轮廓的分布位置和跟座的大小比例.与亚洲其他地区直立人相比,周口店直立人下前臼齿齿冠形态及轮廓形状与淅川标本以及印度尼西亚的S-1相类似,而与S-6差别较大.分析显示周口店直立人下前臼齿与欧洲更新世中期人类有相似的特征,但两者之间的差别更大.
Morphological observation and geometric measurement methods were used to study the distribution of mandibular premolar teeth (P3,72; P4,69) in Zhoukoudian Homo erectus, Australopithecus australassensis, Homo sapiens in Africa, Homo erectus in other Asian regions, Pleistocene in Europe, modern Chinese ), The results showed that the morphological structure and contour shape of the occlusal surface of the premolar molar under crown showed a significant evolutionary change.The anterior premolars of the Australopithecus quadratus had an asymmetric profile of the crown, near the buccal side and obvious vertical grooves in the far middle; P3 Occlusal anterior concave crack, followed by a larger seat; P4 near the buccal cusp, distal vertical groove obvious; appear “H ” type of trenches These characteristics in late fossil humans have varying degrees of performance, but showed a tendency to weaken The profile of the crown of P3 and P4 in modern people is basically symmetrical, the near and far vertical crests in the buccal crest of the crown have disappeared or faint, and the constriction of the seat has been reduced.This study found that the lower molars of Zhoukoudian Homo erectus retained many primitive features of early humans, including In addition, there were obvious internal variations in the morphology of the crown of P3 and P4 of the orthodontic persons in Zhoukoudian, including the buccal side near and far from the vertical groove, Contour pair The distribution of the tooth tip region relative to the outer contour and the size ratio of the seat with the seat.Compared with other Homo sapiens in other parts of Asia, the morphology and contour of the crown of the lower premolars and the Xichuan specimen in Zhoukoudian and the S-1 phase in Indonesia Similar to that of S-6, but analysis showed that the lower premolar teeth of Zhoukoudian Homo erectus had similar characteristics with humans in mid-Pleistocene, but the differences between them were even greater.