The individual-count method of bilateral nonmetric traits has been widely used despite its apparent defects in both theory and practice. Logically, its use means adopting the false concept of ‘two thresholds’ based on the single-liability model. This conceptual defect can create actual problems, in cluding that of conventional ‘tetrachoric correlation.’ The correlation coefficient calculated by formally applying the tetrachoric procedure to the individual-count frequencies is mathematically meaningless because there exists no true liability and threshold that can explain such data. Moreover, it considerably underestimates the correlation if it is used as the estimate of the correlation between the individual-specific components of liability because it neglects the contribution of the inter-side component in the variance of total liability. Two statistical methods are proposed to estimate the correlation coefficient between inter-individual components of liability and its confidence interval. Some selected data from the database published by Ossenberg on the Internet were used to illustrate the utility of the new methods and to examine the problem of the conventional method. The method of estimation of the correlation between the inter-individual components of liability based on the combination of two dual-liability mod els provided, as a by-product, substantial support for the standard threshold model based on data. Be cause the conventional ‘tetrachoric correlations’ proved to seriously underestimate the correlations, the results of almost all studies using Mahalanobis distances based on nonmetric traits so far published may require re-evaluation. It is also argued that a fundamental problem exists in the use of the individu -al-count method itself. Adopting an incorrect method for maintaining comparability is a vicious cycle. It is necessary to emphasize improving the reliability of future studies based on true statistics rather than keeping the comparability between less reliable results based on the false concept of threshold.
{"title":"Tetrachoric correlation of bilateral nonmetric traits: a defect in the conventional procedure and a proposal for two alternative estimation methods","authors":"A. Tagaya","doi":"10.1537/ASE.190227","DOIUrl":"https://doi.org/10.1537/ASE.190227","url":null,"abstract":"The individual-count method of bilateral nonmetric traits has been widely used despite its apparent defects in both theory and practice. Logically, its use means adopting the false concept of ‘two thresholds’ based on the single-liability model. This conceptual defect can create actual problems, in cluding that of conventional ‘tetrachoric correlation.’ The correlation coefficient calculated by formally applying the tetrachoric procedure to the individual-count frequencies is mathematically meaningless because there exists no true liability and threshold that can explain such data. Moreover, it considerably underestimates the correlation if it is used as the estimate of the correlation between the individual-specific components of liability because it neglects the contribution of the inter-side component in the variance of total liability. Two statistical methods are proposed to estimate the correlation coefficient between inter-individual components of liability and its confidence interval. Some selected data from the database published by Ossenberg on the Internet were used to illustrate the utility of the new methods and to examine the problem of the conventional method. The method of estimation of the correlation between the inter-individual components of liability based on the combination of two dual-liability mod els provided, as a by-product, substantial support for the standard threshold model based on data. Be cause the conventional ‘tetrachoric correlations’ proved to seriously underestimate the correlations, the results of almost all studies using Mahalanobis distances based on nonmetric traits so far published may require re-evaluation. It is also argued that a fundamental problem exists in the use of the individu -al-count method itself. Adopting an incorrect method for maintaining comparability is a vicious cycle. It is necessary to emphasize improving the reliability of future studies based on true statistics rather than keeping the comparability between less reliable results based on the false concept of threshold.","PeriodicalId":50751,"journal":{"name":"Anthropological Science","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1537/ASE.190227","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67029966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"社会学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ryohei Takahashi, Ryoko Koibuchi, Fumiko Saeki, Yasuo Hagihara, M. Yoneda, Noboru Adachi, T. Nara
Recent studies have revealed that the Jomon people are considerably genetically different from any other population, including modern-day Japanese. This gives rise to an intriguing question: when after the Jomon era did this drastic change of genetic features occur? The Shomyoji shell midden site in Kanagawa, Japan can provide some clues to address this question. The skeletons buried at this site include some that are more recent than the Jomon-era skeletons with whom they are almost contiguous-ly buried. We tested the genetic continuity of the Shomyoji shell midden people by analyzing mitochondrial DNA (mtDNA). Our results show that the mtDNA haplogroups of the Kofun and Heian skeletons vastly differ from those of the Jomon skeletons. This finding implies that the genetic conversion of the Japanese people may have occurred during or before the Kofun era, at least at the Shomyoji site. To confirm this hypothesis, nuclear genome analysis of the Shomyoji people is considered promising.
{"title":"Mitochondrial DNA analysis of the human skeletons excavated from the Shomyoji shell midden site, Kanagawa, Japan","authors":"Ryohei Takahashi, Ryoko Koibuchi, Fumiko Saeki, Yasuo Hagihara, M. Yoneda, Noboru Adachi, T. Nara","doi":"10.1537/ASE.190307","DOIUrl":"https://doi.org/10.1537/ASE.190307","url":null,"abstract":"Recent studies have revealed that the Jomon people are considerably genetically different from any other population, including modern-day Japanese. This gives rise to an intriguing question: when after the Jomon era did this drastic change of genetic features occur? The Shomyoji shell midden site in Kanagawa, Japan can provide some clues to address this question. The skeletons buried at this site include some that are more recent than the Jomon-era skeletons with whom they are almost contiguous-ly buried. We tested the genetic continuity of the Shomyoji shell midden people by analyzing mitochondrial DNA (mtDNA). Our results show that the mtDNA haplogroups of the Kofun and Heian skeletons vastly differ from those of the Jomon skeletons. This finding implies that the genetic conversion of the Japanese people may have occurred during or before the Kofun era, at least at the Shomyoji site. To confirm this hypothesis, nuclear genome analysis of the Shomyoji people is considered promising.","PeriodicalId":50751,"journal":{"name":"Anthropological Science","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1537/ASE.190307","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67030006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"社会学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
human African Africa. Human ancestors bipedal locomotion in Africa this time a ear-lier. Many models have suggested how erect bipedalism may have begun. Fossils are useful for indicating the time and place of evolutionary processes, but locomotion traits should be compared and discussed based on living animals because fossils cannot walk themselves. Explanation of fossil locomotion can be sought only from extant animals. Comparative kinesiology of living nonhuman primates is an important method of analysis to clarify the process of human Abstract Recent fossil records have suggested that human erect bipedal locomotion started in Africa probably more than 6 million years ago. However, debate continues regarding how locomotion was acquired by our prehuman ancestors. Fossils and the genetic traits of recent humans and animals cannot answer this question directly. Therefore, the present paper reviews acquisition models of human bipedalism and explanations regarding how humans acquired bipedalism based on a comparative kinesiology of contemporary mammal species. Nonhuman primates are adequate models of human bipedal acquisition because of not only the phylogenetically close relationship with humans, but also the trend toward hindlimb dominance and orthograde positional behavior in daily life. Although dissimilar to the erect bipedalism seen in humans, nonhuman primates adopt bipedal positional behavior in the wild. All nonhuman primates use the arboreal environment, but some groups of species utilize the ground predomi-nantly. Compared with relatively terrestrial nonhuman primates, relatively arboreal primates show more similarities with humans in their bipedal locomotion. Comparisons among primate species and between nonhuman primates and nonprimate mammals indicate that human-like bipedal characteristics are strongly related to arboreal life. Our prehuman ancestors likely started and adapted to bipedal locomotion while living in trees; this process is referred to as the generalized arboreal activity model. When humans began terrestrial locomotion, they likely performed proficient bipedalism from the first step. The generalized arboreal activity model presented here does not contradict the fossil records.
{"title":"How did humans acquire erect bipedal walking?","authors":"Tasuku Kimura","doi":"10.1537/ASE.190219","DOIUrl":"https://doi.org/10.1537/ASE.190219","url":null,"abstract":"human African Africa. Human ancestors bipedal locomotion in Africa this time a ear-lier. Many models have suggested how erect bipedalism may have begun. Fossils are useful for indicating the time and place of evolutionary processes, but locomotion traits should be compared and discussed based on living animals because fossils cannot walk themselves. Explanation of fossil locomotion can be sought only from extant animals. Comparative kinesiology of living nonhuman primates is an important method of analysis to clarify the process of human Abstract Recent fossil records have suggested that human erect bipedal locomotion started in Africa probably more than 6 million years ago. However, debate continues regarding how locomotion was acquired by our prehuman ancestors. Fossils and the genetic traits of recent humans and animals cannot answer this question directly. Therefore, the present paper reviews acquisition models of human bipedalism and explanations regarding how humans acquired bipedalism based on a comparative kinesiology of contemporary mammal species. Nonhuman primates are adequate models of human bipedal acquisition because of not only the phylogenetically close relationship with humans, but also the trend toward hindlimb dominance and orthograde positional behavior in daily life. Although dissimilar to the erect bipedalism seen in humans, nonhuman primates adopt bipedal positional behavior in the wild. All nonhuman primates use the arboreal environment, but some groups of species utilize the ground predomi-nantly. Compared with relatively terrestrial nonhuman primates, relatively arboreal primates show more similarities with humans in their bipedal locomotion. Comparisons among primate species and between nonhuman primates and nonprimate mammals indicate that human-like bipedal characteristics are strongly related to arboreal life. Our prehuman ancestors likely started and adapted to bipedal locomotion while living in trees; this process is referred to as the generalized arboreal activity model. When humans began terrestrial locomotion, they likely performed proficient bipedalism from the first step. The generalized arboreal activity model presented here does not contradict the fossil records.","PeriodicalId":50751,"journal":{"name":"Anthropological Science","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1537/ASE.190219","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67029958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"社会学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The relationship between calcaneal size and body mass in extant primates and other land mammals is examined using regression analyses to provide simple equations for estimating the body mass of extinct primate and land mammal species based on the calcaneus. The results imply that among the linear calcaneal dimensions, the calcaneal width at the talar articular surfaces (CA2) is likely the best body mass estimator for land mammals (including primates), and the width of the posterior talar articular surface (CA3) appears to be relatively good body mass estimator for primates. The equation with a 95% prediction interval for estimating the body mass (BM, in g) using CA2 (in mm) for land mammals is: BM = exp(2.928 × ln CA2 + 0.981 ± 0.772) × 1.076; the corresponding equation using CA3 (in mm) for primates is: BM = exp(2.555 × ln CA3 + 3.536 ± 0.641) × 1.067.
{"title":"Relationship between the calcaneal size and body mass in primates and land mammals","authors":"T. Tsubamoto","doi":"10.1537/ASE.190221","DOIUrl":"https://doi.org/10.1537/ASE.190221","url":null,"abstract":"The relationship between calcaneal size and body mass in extant primates and other land mammals is examined using regression analyses to provide simple equations for estimating the body mass of extinct primate and land mammal species based on the calcaneus. The results imply that among the linear calcaneal dimensions, the calcaneal width at the talar articular surfaces (CA2) is likely the best body mass estimator for land mammals (including primates), and the width of the posterior talar articular surface (CA3) appears to be relatively good body mass estimator for primates. The equation with a 95% prediction interval for estimating the body mass (BM, in g) using CA2 (in mm) for land mammals is: BM = exp(2.928 × ln CA2 + 0.981 ± 0.772) × 1.076; the corresponding equation using CA3 (in mm) for primates is: BM = exp(2.555 × ln CA3 + 3.536 ± 0.641) × 1.067.","PeriodicalId":50751,"journal":{"name":"Anthropological Science","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1537/ASE.190221","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67029961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"社会学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Ortiz, Yingqi Zhang, Chang-zhu Jin, Yuan Wang, Min Zhu, Yaling Yan, Clare M Kimock, C. Villamil, K. He, T. Harrison
This study investigates the morphological variation and taxonomic affinities of 28 fossil gibbon molars from eight newly discovered Pleistocene cave sites in the area of Chongzuo, Guangxi Zhuang Autonomous Region, China. A recent descriptive analysis demonstrated that these fossil teeth form a uniform group that can be assigned to a single species of Nomascus . In this contribution, a two-dimensional morphometric approach is employed to examine the Chongzuo specimens in comparison with a large sample of extant hylobatids, as well as with previously reported hylobatid dental remains from the Pleistocene of China. Buccolingual and mesiodistal measurements and crown outline areas reveal that the Chongzuo molars correspond most closely with Nomascus and, to a lesser extent, Hoolock . Crown shape was investigated using elliptical Fourier analysis. Our results show that the Chongzuo specimens fall in most cases either within the range of variation of extant Nomascus to the exclusion of all other hylobatid genera, or their distance from the cluster represented by the Nomascus sample is relatively small. Similarly, the Mahalanobis distances for crown shape show a trend towards smaller morphological distances between the Chongzuo specimens and Nomascus , followed by Hoolock and Hylobates . The Chongzuo molars are also morphometrically distinct from Bunopithecus sericus , but fall within the range of overlap of other Pleistocene hylobatid dental remains from southern China. The balance of evidence indicates that the Chongzuo teeth can be attributed to cf. Nomascus . The fossil teeth are sufficiently distinct from those of extant Nomascus that they may represent an extinct species.
{"title":"Morphometric analysis of fossil hylobatid molars from the Pleistocene of southern China","authors":"A. Ortiz, Yingqi Zhang, Chang-zhu Jin, Yuan Wang, Min Zhu, Yaling Yan, Clare M Kimock, C. Villamil, K. He, T. Harrison","doi":"10.1537/ASE.190331","DOIUrl":"https://doi.org/10.1537/ASE.190331","url":null,"abstract":"This study investigates the morphological variation and taxonomic affinities of 28 fossil gibbon molars from eight newly discovered Pleistocene cave sites in the area of Chongzuo, Guangxi Zhuang Autonomous Region, China. A recent descriptive analysis demonstrated that these fossil teeth form a uniform group that can be assigned to a single species of Nomascus . In this contribution, a two-dimensional morphometric approach is employed to examine the Chongzuo specimens in comparison with a large sample of extant hylobatids, as well as with previously reported hylobatid dental remains from the Pleistocene of China. Buccolingual and mesiodistal measurements and crown outline areas reveal that the Chongzuo molars correspond most closely with Nomascus and, to a lesser extent, Hoolock . Crown shape was investigated using elliptical Fourier analysis. Our results show that the Chongzuo specimens fall in most cases either within the range of variation of extant Nomascus to the exclusion of all other hylobatid genera, or their distance from the cluster represented by the Nomascus sample is relatively small. Similarly, the Mahalanobis distances for crown shape show a trend towards smaller morphological distances between the Chongzuo specimens and Nomascus , followed by Hoolock and Hylobates . The Chongzuo molars are also morphometrically distinct from Bunopithecus sericus , but fall within the range of overlap of other Pleistocene hylobatid dental remains from southern China. The balance of evidence indicates that the Chongzuo teeth can be attributed to cf. Nomascus . The fossil teeth are sufficiently distinct from those of extant Nomascus that they may represent an extinct species.","PeriodicalId":50751,"journal":{"name":"Anthropological Science","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1537/ASE.190331","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67030010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"社会学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Primate hands and feet are versatile and offer an opportunity to examine how morphology reflects compromises among different functions in daily activities. In this study, we investigated the di aphyseal robusticity of metacarpals (MCs) and metatarsals (MTs) and discussed their correlation with locomotor and other behaviors in the semiterrestrial Japanese macaque ( Macaca fuscata ). The objectives of this study were to determine (1) whether more robust MCs and MTs experience higher forces during terrestrial locomotion than less robust bones; and (2) whether MT3, which is suggested to be the functional axis of the foot in Japanese macaques, is more robust than MT2, MT4, and MT5. Computed tomography of MCs1–5 and MTs1–5 was performed in 10 monkeys. As a measure of bone robusticity, the buckling strength of each MT and MC was calculated as J / L 2 where J is the polar second moment of area and L is the bone length. Hand and foot pressure were recorded using plantar pressure measurement systems while two monkeys moved on a flat floor over a range of speeds (0.72–2.56 m/s). The relation ship between the bone robusticity and the load applied to the bones during terrestrial locomotion was analyzed. Our results did not support the two predictions. There was no positive correlation between diaphyseal robusticity and the peak force in both male and female Japanese macaques. There was no clear difference in bone robusticity among MTs2–5 in both males and females. These results suggest that the relation between MC and MT robusticity and mechanical loading during locomotion is not as straightforward as might be expected, possibly due to the complex multifunctionality of primate hands and feet. Additional integrative studies that similarly incorporate morphological and experimental approaches are expected to provide useful insights into macaque hand and foot morphology.
灵长类动物的手和脚是多功能的，这为研究形态学如何反映日常活动中不同功能之间的妥协提供了机会。本研究研究了半陆栖日本猕猴(Macaca fuscata)掌骨(MCs)和跖骨(MTs)的骨干强健性，并讨论了它们与运动和其他行为的关系。本研究的目的是确定(1)在陆地运动中，强壮的MCs和MTs是否比不强壮的骨头承受更大的力;(2)被认为是日本猕猴足部功能轴的MT3是否比MT2、MT4和MT5更健壮。对10只猴子进行MCs1-5和MTs1-5的计算机断层扫描。作为骨鲁棒性的度量，每个MT和MC的屈曲强度计算为J / L 2，其中J为面积的极秒矩，L为骨长度。当两只猴子在平坦的地板上以不同的速度(0.72-2.56米/秒)移动时，使用足底压力测量系统记录了手和脚的压力。分析了地面运动时骨的鲁棒性与骨所受载荷的关系。我们的结果不支持这两个预测。在雄性和雌性日本猕猴中，干骺端健壮性与峰值力之间没有正相关。在男性和女性中，MTs2-5的骨健全性没有明显差异。这些结果表明，在运动过程中，MC和MT鲁棒性与机械负荷之间的关系并不像预期的那样简单，可能是由于灵长类动物的手和脚具有复杂的多功能性。另外的综合研究，类似地结合形态学和实验方法，有望提供有用的见解猕猴的手和足形态。
{"title":"Integrative experimental and morphological study of the metacarpal and metatarsal bones of the Japanese macaque (Macaca fuscata)","authors":"Yasuo Higurashi, Ryosuke Goto, Y. Nakano","doi":"10.1537/ASE.190511","DOIUrl":"https://doi.org/10.1537/ASE.190511","url":null,"abstract":"Primate hands and feet are versatile and offer an opportunity to examine how morphology reflects compromises among different functions in daily activities. In this study, we investigated the di aphyseal robusticity of metacarpals (MCs) and metatarsals (MTs) and discussed their correlation with locomotor and other behaviors in the semiterrestrial Japanese macaque ( Macaca fuscata ). The objectives of this study were to determine (1) whether more robust MCs and MTs experience higher forces during terrestrial locomotion than less robust bones; and (2) whether MT3, which is suggested to be the functional axis of the foot in Japanese macaques, is more robust than MT2, MT4, and MT5. Computed tomography of MCs1–5 and MTs1–5 was performed in 10 monkeys. As a measure of bone robusticity, the buckling strength of each MT and MC was calculated as J / L 2 where J is the polar second moment of area and L is the bone length. Hand and foot pressure were recorded using plantar pressure measurement systems while two monkeys moved on a flat floor over a range of speeds (0.72–2.56 m/s). The relation ship between the bone robusticity and the load applied to the bones during terrestrial locomotion was analyzed. Our results did not support the two predictions. There was no positive correlation between diaphyseal robusticity and the peak force in both male and female Japanese macaques. There was no clear difference in bone robusticity among MTs2–5 in both males and females. These results suggest that the relation between MC and MT robusticity and mechanical loading during locomotion is not as straightforward as might be expected, possibly due to the complex multifunctionality of primate hands and feet. Additional integrative studies that similarly incorporate morphological and experimental approaches are expected to provide useful insights into macaque hand and foot morphology.","PeriodicalId":50751,"journal":{"name":"Anthropological Science","volume":"27 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67030012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"社会学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tsuyoshi Ito, R. Kimura, Azusa Ryukoden, Nanae Tsuchiya, S. Murayama, H. Ishida
Using computed tomography, we examined the surface and internal morphologies of the upper face of people living on the Ryukyu Islands and mainland Japanese, focusing on the nasal root protrusion and eyeball position. The results showed that the nasal root protrusion on the surface was influenced by a combination of changes in both hard and soft tissues, such as skeletal nasal protrusion, eyeball recession, and skin thickness. The eyeball position became more posterior as the orbital cavity height and depth increased. Compared with people originating from mainland Japan, Ryukyu Islanders had a more prominent nasal root at both surface and skeletal levels, and a lower orbital rim relative to its internal height. However, a significant difference in the eyeball position and skin thickness was not detected. Therefore, the skeletal nasal root protrusion, not soft tissue configuration, is likely to account for the difference in the surface nasal root protrusion between the two populations. These findings will contribute to a better understanding of the association between hard and soft tissue configurations and the diversification of human facial features at the individual and population levels.
{"title":"Computed tomography examinations of the surface and internal morphologies of the upper face in Ryukyu Islanders and mainland Japanese population","authors":"Tsuyoshi Ito, R. Kimura, Azusa Ryukoden, Nanae Tsuchiya, S. Murayama, H. Ishida","doi":"10.1537/ASE.180922","DOIUrl":"https://doi.org/10.1537/ASE.180922","url":null,"abstract":"Using computed tomography, we examined the surface and internal morphologies of the upper face of people living on the Ryukyu Islands and mainland Japanese, focusing on the nasal root protrusion and eyeball position. The results showed that the nasal root protrusion on the surface was influenced by a combination of changes in both hard and soft tissues, such as skeletal nasal protrusion, eyeball recession, and skin thickness. The eyeball position became more posterior as the orbital cavity height and depth increased. Compared with people originating from mainland Japan, Ryukyu Islanders had a more prominent nasal root at both surface and skeletal levels, and a lower orbital rim relative to its internal height. However, a significant difference in the eyeball position and skin thickness was not detected. Therefore, the skeletal nasal root protrusion, not soft tissue configuration, is likely to account for the difference in the surface nasal root protrusion between the two populations. These findings will contribute to a better understanding of the association between hard and soft tissue configurations and the diversification of human facial features at the individual and population levels.","PeriodicalId":50751,"journal":{"name":"Anthropological Science","volume":"126 1","pages":"123-133"},"PeriodicalIF":0.7,"publicationDate":"2018-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42349339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"社会学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We studied the relationship of tooth agenesis with tooth size and its proportional variability (PV) based on mesiodistal crown diameters of 276 Japanese males including 49 individuals for reference. Tooth agenesis was classified into third molar agenesis, hypodontia, and multiple agenesis. In addition, third molar agenesis was classified into four types according to the number of congenitally missing third molars. PV was measured by standard deviation of log-transformed data. The size of remaining teeth was generally larger in the agenesis groups than in the reference group, and largest in individuals with hypodontia, followed by those with multiple agenesis and those with third molar agenesis. The findings suggest the existence of two types of tooth agenesis differing in nature, where remaining teeth tend to enlarge in the ‘moderate type’ and reduce in the ‘degenerative type.’ The former is dominant in (tooth agenesis of) the Japanese, whereas the latter seems to be more prevalent in European descendants, which is in accordance with recent findings in genetics. The ‘moderate type’ might be advantageous for survival in human microevolution because of its improved function and reduced risk of dentoskeletal discrepancies. The PV of tooth size was greater in the agenesis groups than in the reference group except for premolars and second molars. Among those with third molar agenesis, the greatest increase in PV was exhibited by those with all third molars missing, followed by those with two third molars missing. Among remaining teeth, canines and first molars tended to exhibit a greater increase of PV in agenesis groups, whereas their magnitude of PV did not exceed that of other teeth. These results can be explained by the genetic stability of canines and first molars and an increased variation due to common factors across remaining teeth associated with tooth agenesis.
{"title":"Tooth size and its proportional variability in Japanese males with agenesis in permanent dentition","authors":"Hiroyuki Yamada, A. Tagaya","doi":"10.1537/ASE.180529","DOIUrl":"https://doi.org/10.1537/ASE.180529","url":null,"abstract":"We studied the relationship of tooth agenesis with tooth size and its proportional variability (PV) based on mesiodistal crown diameters of 276 Japanese males including 49 individuals for reference. Tooth agenesis was classified into third molar agenesis, hypodontia, and multiple agenesis. In addition, third molar agenesis was classified into four types according to the number of congenitally missing third molars. PV was measured by standard deviation of log-transformed data. The size of remaining teeth was generally larger in the agenesis groups than in the reference group, and largest in individuals with hypodontia, followed by those with multiple agenesis and those with third molar agenesis. The findings suggest the existence of two types of tooth agenesis differing in nature, where remaining teeth tend to enlarge in the ‘moderate type’ and reduce in the ‘degenerative type.’ The former is dominant in (tooth agenesis of) the Japanese, whereas the latter seems to be more prevalent in European descendants, which is in accordance with recent findings in genetics. The ‘moderate type’ might be advantageous for survival in human microevolution because of its improved function and reduced risk of dentoskeletal discrepancies. The PV of tooth size was greater in the agenesis groups than in the reference group except for premolars and second molars. Among those with third molar agenesis, the greatest increase in PV was exhibited by those with all third molars missing, followed by those with two third molars missing. Among remaining teeth, canines and first molars tended to exhibit a greater increase of PV in agenesis groups, whereas their magnitude of PV did not exceed that of other teeth. These results can be explained by the genetic stability of canines and first molars and an increased variation due to common factors across remaining teeth associated with tooth agenesis.","PeriodicalId":50751,"journal":{"name":"Anthropological Science","volume":"126 1","pages":"75-87"},"PeriodicalIF":0.7,"publicationDate":"2018-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1537/ASE.180529","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49583406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"社会学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Sexual selection and the loss of laryngeal air sacs during the evolution of speech","authors":"J. Dunn","doi":"10.1537/ASE.180309","DOIUrl":"https://doi.org/10.1537/ASE.180309","url":null,"abstract":"","PeriodicalId":50751,"journal":{"name":"Anthropological Science","volume":"126 1","pages":"29-34"},"PeriodicalIF":0.7,"publicationDate":"2018-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1537/ASE.180309","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46488343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"社会学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Electroglottography (EGG) is a low-cost, non-invasive method for documenting laryngeal sound production during vocalization. The EGG signal represents relative vocal-fold contact area and thus delivers physiological evidence of vocal-fold vibration. While the method has received much attention in human voice research over the last five decades, it has seen very little application in other mammals.Here, we give a concise overview of mammalian vocal production principles. We explain how mammalian voice production physiology and the dynamics of vocal-fold vibration can be documented qualitatively and quantitatively with EGG, and we summarize and discuss key issues from research with humans. Finally, we review the limited number of studies applying EGG to non-human mammals, both in vivo and in vitro. The potential of EGG for non-invasive assessment of non-human primate vocalization is demonstrated with novel in vivo data of Cebus albifrons and Ateles chamek vocalization. These examples illustrate the great potential of EGG as a new minimally invasive tool in primate research, which can provide important insight into the ‘black box’ that is vocal production. A better understanding of vocal-fold vibration across a range of taxa can provide us with a deeper understanding of severalimportant elements of speech evolution, such as the universality of vocal production mechanisms, the independence of source and filter, the evolution of vocal control, and the relevance of non-linear phenomena.
{"title":"Non-invasive documentation of primate voice production using electroglottography","authors":"C. Herbst, J. Dunn","doi":"10.1537/ASE.180201","DOIUrl":"https://doi.org/10.1537/ASE.180201","url":null,"abstract":"Electroglottography (EGG) is a low-cost, non-invasive method for documenting laryngeal sound production during vocalization. The EGG signal represents relative vocal-fold contact area and thus delivers physiological evidence of vocal-fold vibration. While the method has received much attention in human voice research over the last five decades, it has seen very little application in other mammals.Here, we give a concise overview of mammalian vocal production principles. We explain how mammalian voice production physiology and the dynamics of vocal-fold vibration can be documented qualitatively and quantitatively with EGG, and we summarize and discuss key issues from research with humans. Finally, we review the limited number of studies applying EGG to non-human mammals, both in vivo and in vitro. The potential of EGG for non-invasive assessment of non-human primate vocalization is demonstrated with novel in vivo data of Cebus albifrons and Ateles chamek vocalization. These examples illustrate the great potential of EGG as a new minimally invasive tool in primate research, which can provide important insight into the ‘black box’ that is vocal production. A better understanding of vocal-fold vibration across a range of taxa can provide us with a deeper understanding of severalimportant elements of speech evolution, such as the universality of vocal production mechanisms, the independence of source and filter, the evolution of vocal control, and the relevance of non-linear phenomena.","PeriodicalId":50751,"journal":{"name":"Anthropological Science","volume":"126 1","pages":"19-27"},"PeriodicalIF":0.7,"publicationDate":"2018-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1537/ASE.180201","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67029853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"社会学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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