Traditional descriptive observation and advanced geometric morphometric are employed to study the morphological characteristics of Zhoukoudian mandibular premolars, and simultaneously with the specimens of Australopit...Traditional descriptive observation and advanced geometric morphometric are employed to study the morphological characteristics of Zhoukoudian mandibular premolars, and simultaneously with the specimens of Australopithecus, African early Homo, Homo erectus in other areas of Asia except Zhoukoudian, Europe Pleistocene fossil hominins, and recent Chinese (72 P3 and 69 P4 on the whole) being included as comparisons. Results suggest obvious evolutionary changes in the occlusal morphology and crown outline shape of mandibular premolars. Australopithecus P3s are found with extremely asymmetrical crown outlines, prominent mesial and distal vertical grooves on the buccal side, open foveas, and well-developed talonids, and P4s with similarly asymmetrical crown outlines, distinct mesial and distal vertical grooves on the buccal side, and "H" type of grooves combination. These characteristics are also expressed in the later hominin specimens, but with a decreased extent and lower frequency. The P3s of recent Chinese, slightly asymmetrical in the crown lingual contours, and P4s, basically symmetrical in the crown outlines, become faint or disappeared in the mesial or distal vertical buccal grooves, and decreased in the talonid size. It is suggested that Zhoukoudian mandibular premolars preserve some primitive traits of earlier hominins, including asymmetrical crown outlines and prominent mesial and distal vertical grooves of buccal side. Moreover, Zhoukoudian specimens exhibit obvious morphological variation between individuals, expressed mainly by aspects of mesial and distal vertical buccal grooves in various degrees, symmetry or asymmetry extent of crown lingual contour, relative location of polygon to the corresponding surrounding outline, as well as the relative size of talonid. When compared with Homo erectus from the other areas of Asia, Zhoukoudian specimens show their similarity with those of Xichuan and S-1, and at the same time great discrepancy with S-6 in the occlusal morphology and crown outline shape. When it comes to the relationship between specimens of Europe Pleistocene and Zhoukoudian, disparity is expressed in a stronger way than the corresponding similarity.展开更多
基金Supported by the National Natural Science Foundation of China (Grant No. 40772016)International Cooperation Program of MST of China (Grant No. 2007DFB20330)Cultural Relics Protected Program in Danjiangkou Reservoir Area of the South-to-North Water Diversion Project Held by Hubei Cultural Relics Bureau (Grant No. NK13)
文摘Traditional descriptive observation and advanced geometric morphometric are employed to study the morphological characteristics of Zhoukoudian mandibular premolars, and simultaneously with the specimens of Australopithecus, African early Homo, Homo erectus in other areas of Asia except Zhoukoudian, Europe Pleistocene fossil hominins, and recent Chinese (72 P3 and 69 P4 on the whole) being included as comparisons. Results suggest obvious evolutionary changes in the occlusal morphology and crown outline shape of mandibular premolars. Australopithecus P3s are found with extremely asymmetrical crown outlines, prominent mesial and distal vertical grooves on the buccal side, open foveas, and well-developed talonids, and P4s with similarly asymmetrical crown outlines, distinct mesial and distal vertical grooves on the buccal side, and "H" type of grooves combination. These characteristics are also expressed in the later hominin specimens, but with a decreased extent and lower frequency. The P3s of recent Chinese, slightly asymmetrical in the crown lingual contours, and P4s, basically symmetrical in the crown outlines, become faint or disappeared in the mesial or distal vertical buccal grooves, and decreased in the talonid size. It is suggested that Zhoukoudian mandibular premolars preserve some primitive traits of earlier hominins, including asymmetrical crown outlines and prominent mesial and distal vertical grooves of buccal side. Moreover, Zhoukoudian specimens exhibit obvious morphological variation between individuals, expressed mainly by aspects of mesial and distal vertical buccal grooves in various degrees, symmetry or asymmetry extent of crown lingual contour, relative location of polygon to the corresponding surrounding outline, as well as the relative size of talonid. When compared with Homo erectus from the other areas of Asia, Zhoukoudian specimens show their similarity with those of Xichuan and S-1, and at the same time great discrepancy with S-6 in the occlusal morphology and crown outline shape. When it comes to the relationship between specimens of Europe Pleistocene and Zhoukoudian, disparity is expressed in a stronger way than the corresponding similarity.
