Preliminary study on enamel microstructure of 5 lower permanent incisors of Late Mio-cene Yuanmou hominoids was conducted using a scanning electron microscope (SEM). The enamel incremental markings, as well as perikym...Preliminary study on enamel microstructure of 5 lower permanent incisors of Late Mio-cene Yuanmou hominoids was conducted using a scanning electron microscope (SEM). The enamel incremental markings, as well as perikymata spacing and its periodicity were observed and counted. Using the perikymata number and periodicity, the crown formation times of the incisors are estimated. The transverse and longitudinal microstructures of the enamel prisms are also ob-served. Comparison of the dental development and enamel microstructure features of Yuanmou hominoids with those of Lufeng hominoids shows that there are similarities and also some differ-ences between them. The relationship between Yuanmou hominoids and early hominids is dis-cussed.展开更多
Analysis of 3D measurements of 13 landmarks on 72 Yuanmou Hominoid lower molars and some comparative samples, using Euclidean Distance Matrix Analysis (EDMA), show that the 3D morphometric features of Yuanmou Homi noi...Analysis of 3D measurements of 13 landmarks on 72 Yuanmou Hominoid lower molars and some comparative samples, using Euclidean Distance Matrix Analysis (EDMA), show that the 3D morphometric features of Yuanmou Homi noid lower molars largely resemble those of Lufengpithecus. Compared with extant great apes and humans, both Yuanmou Hominoid and Lufengpithecus differ markedly from humans, whereas they show much resemblance to apes. The two Chinese hominoids and extant great apes are different from humans in many of the same ways. Moreover, 3D morphometric features of Yuanmou Hominoid lower molars differ from those of each of the three extant great apes in similar ways. Of the three, the orangutan is the closest match to Yuanmou Hominoid in tooth morphology. However, the exact implications of these similarities and differences remain to be determined.展开更多
Mesial-distal and buccal-lingual dimensions of 1 266 hominoid teeth found in Yuanmou of Yunnan Province during the period of 1986 and 1988 have been measured. The statistical analyses of the metric data show that the ...Mesial-distal and buccal-lingual dimensions of 1 266 hominoid teeth found in Yuanmou of Yunnan Province during the period of 1986 and 1988 have been measured. The statistical analyses of the metric data show that the tooth sizes of Yuanmou hominoid can be divided into big and small two types, and most tooth dimensions display obvious bimodalities in both histograms and 2 dimensional plots. The coefficients of variance (CV) reveal that the CVs of Yuanmou hominoid tooth sizes are within or close to the CV ranges of Lufengpithecus and extant great apes. The comparisons of tooth sizes and their proportions indicate that Yuanmou hominoids have close affinities with Lefeng and Kaiyuan hominoids, and have obvious differences with Gorilla, Chimpanzee and Orangutan. The authors believe that the hominoid fossils found in Yuanmou in the past 10 years represent a single species with highly sexual dimorphism in morphology and this species may have a close evolutionary relationship with the hominoids found in展开更多
The two sections containing hominoid fossils in the Yuanmou Basin, Yunnan Prov-ince have been studied by means of magnetostratigraphy. The results are as follows. The Xiaohe section records over 8 polarity zones corre...The two sections containing hominoid fossils in the Yuanmou Basin, Yunnan Prov-ince have been studied by means of magnetostratigraphy. The results are as follows. The Xiaohe section records over 8 polarity zones corresponding to Cande-Kent95 time scale, including C3Br.1n, C3Br.1r, C3Br.2n, C3Br.2r, C4n.1n, C4n.1r, C4n.2n and C4n.2r, attaching to Late Mio-cene. This section comprises two layers of hominoid fossils: the lower layer (the 1st layer in fig. 4) which records the lower portion of C4n.2r with paleomagnetic age of 8.20—8.10 Ma and the upper layer (the 16th layer in fig. 4) which records C3Br.1r with paleomagnetic age of 7.20—7.15 Ma. So the age of hominoid fossils in the Xiaohe section is about 8.20—7.15 Ma. The Leilao section records over 11 polarity zones corresponding to Cande-Kent95 time scale, including C3Br, C3Br.1n, C3Br.1r, C3Br.2n, C3Br.2r, C4n.1n, C4n.1r, C4n.2n, C4n.2r, C4n.3n and C4n.3r, attaching to Late Miocene. This section also consists of two layers of hominoid fossils: the lower layer (the 3rd layer in fig. 3) which records C4n.2r with the age of 8.20—8.10 Ma and the upper layer(the 19th layer in fig. 3) which records the middle portion of C3Br with the age of 7.15—7.1 Ma. So the age of hominoid fossils in the Leilao section is about 8.20—7.10 Ma. Sedimentary environments reflected in both sections are extremely similar, and the ages of hominoid fossils are of correspondency. The age of the lower and upper fossil layers is 8.20—8.10 Ma and 7.20—7.10 Ma respectively, which probably imply that hominoids living in Xiaohe and Leilao basins have uniform activity areas. There were hominoids activities all along during 8.00—7.00 MaBP in this field.展开更多
基金the National Key Research Project of China(Grant No.95-01)the National Natural Science Foundation of China(Grant No.40002003) the Chinese Academy of Sciences(Grant No.970402).
文摘Preliminary study on enamel microstructure of 5 lower permanent incisors of Late Mio-cene Yuanmou hominoids was conducted using a scanning electron microscope (SEM). The enamel incremental markings, as well as perikymata spacing and its periodicity were observed and counted. Using the perikymata number and periodicity, the crown formation times of the incisors are estimated. The transverse and longitudinal microstructures of the enamel prisms are also ob-served. Comparison of the dental development and enamel microstructure features of Yuanmou hominoids with those of Lufeng hominoids shows that there are similarities and also some differ-ences between them. The relationship between Yuanmou hominoids and early hominids is dis-cussed.
文摘Analysis of 3D measurements of 13 landmarks on 72 Yuanmou Hominoid lower molars and some comparative samples, using Euclidean Distance Matrix Analysis (EDMA), show that the 3D morphometric features of Yuanmou Homi noid lower molars largely resemble those of Lufengpithecus. Compared with extant great apes and humans, both Yuanmou Hominoid and Lufengpithecus differ markedly from humans, whereas they show much resemblance to apes. The two Chinese hominoids and extant great apes are different from humans in many of the same ways. Moreover, 3D morphometric features of Yuanmou Hominoid lower molars differ from those of each of the three extant great apes in similar ways. Of the three, the orangutan is the closest match to Yuanmou Hominoid in tooth morphology. However, the exact implications of these similarities and differences remain to be determined.
文摘Mesial-distal and buccal-lingual dimensions of 1 266 hominoid teeth found in Yuanmou of Yunnan Province during the period of 1986 and 1988 have been measured. The statistical analyses of the metric data show that the tooth sizes of Yuanmou hominoid can be divided into big and small two types, and most tooth dimensions display obvious bimodalities in both histograms and 2 dimensional plots. The coefficients of variance (CV) reveal that the CVs of Yuanmou hominoid tooth sizes are within or close to the CV ranges of Lufengpithecus and extant great apes. The comparisons of tooth sizes and their proportions indicate that Yuanmou hominoids have close affinities with Lefeng and Kaiyuan hominoids, and have obvious differences with Gorilla, Chimpanzee and Orangutan. The authors believe that the hominoid fossils found in Yuanmou in the past 10 years represent a single species with highly sexual dimorphism in morphology and this species may have a close evolutionary relationship with the hominoids found in
文摘The two sections containing hominoid fossils in the Yuanmou Basin, Yunnan Prov-ince have been studied by means of magnetostratigraphy. The results are as follows. The Xiaohe section records over 8 polarity zones corresponding to Cande-Kent95 time scale, including C3Br.1n, C3Br.1r, C3Br.2n, C3Br.2r, C4n.1n, C4n.1r, C4n.2n and C4n.2r, attaching to Late Mio-cene. This section comprises two layers of hominoid fossils: the lower layer (the 1st layer in fig. 4) which records the lower portion of C4n.2r with paleomagnetic age of 8.20—8.10 Ma and the upper layer (the 16th layer in fig. 4) which records C3Br.1r with paleomagnetic age of 7.20—7.15 Ma. So the age of hominoid fossils in the Xiaohe section is about 8.20—7.15 Ma. The Leilao section records over 11 polarity zones corresponding to Cande-Kent95 time scale, including C3Br, C3Br.1n, C3Br.1r, C3Br.2n, C3Br.2r, C4n.1n, C4n.1r, C4n.2n, C4n.2r, C4n.3n and C4n.3r, attaching to Late Miocene. This section also consists of two layers of hominoid fossils: the lower layer (the 3rd layer in fig. 3) which records C4n.2r with the age of 8.20—8.10 Ma and the upper layer(the 19th layer in fig. 3) which records the middle portion of C3Br with the age of 7.15—7.1 Ma. So the age of hominoid fossils in the Leilao section is about 8.20—7.10 Ma. Sedimentary environments reflected in both sections are extremely similar, and the ages of hominoid fossils are of correspondency. The age of the lower and upper fossil layers is 8.20—8.10 Ma and 7.20—7.10 Ma respectively, which probably imply that hominoids living in Xiaohe and Leilao basins have uniform activity areas. There were hominoids activities all along during 8.00—7.00 MaBP in this field.
