{"title":"整合下颌证据评估南方古猿阿法种上颌骨形态变异。","authors":"Hester Hanegraef, Romain David, Fred Spoor","doi":"10.1002/ar.70027","DOIUrl":null,"url":null,"abstract":"<p><p>Geometric morphometric analyses are used to explore variation of maxillary dental arcades of Australopithecus afarensis, expanding on the work of Hanegraef and Spoor, 2025 (Morphological variation of the Australopithecus afarensis maxilla. Journal of Human Evolution, 201, 103651) by integrating evidence from a large sample of virtually reconstructed mandibles. Size and shape of maxillary dental arcades can be predicted accurately from mandibular landmarks based on strong covariation between occluding upper and lower dentitions, and a novel method was developed to correct for reduced shape variation in these predictions. As predictions are restricted to the alveolar process, morphological information about the rest of the maxilla is lost. The trade-off between a smaller sample with comprehensive morphology and a larger sample with restricted morphology is discussed. Here, we analyzed 9 original and 17 predicted A. afarensis dental arcades in the comparative context of 448 extant hominine (modern human and African ape) maxillae. This study found that (1) degrees of size and shape variation are high in A. afarensis, potentially even higher than in Gorilla species when including the predictions in the fossil sample, (2) no allometry was detected, even when expanding the A. afarensis sample with predictions, (3) size and shape do not significantly change over time when analyzing original and predicted A. afarensis dental arcades together, and (4) sexual form and shape dimorphism, but not sexual size differences, are reduced when including A. afarensis predictions in the fossil sample. Our results quantifying the range and pattern of variation of the A. afarensis maxilla provide a comparative context when assessing whether or not other Plio-Pleistocene hominin specimens are conspecific.</p>","PeriodicalId":520555,"journal":{"name":"Anatomical record (Hoboken, N.J. : 2007)","volume":" ","pages":""},"PeriodicalIF":2.1000,"publicationDate":"2025-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Integrating mandibular evidence to assess morphological variation of the Australopithecus afarensis maxilla.\",\"authors\":\"Hester Hanegraef, Romain David, Fred Spoor\",\"doi\":\"10.1002/ar.70027\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>Geometric morphometric analyses are used to explore variation of maxillary dental arcades of Australopithecus afarensis, expanding on the work of Hanegraef and Spoor, 2025 (Morphological variation of the Australopithecus afarensis maxilla. Journal of Human Evolution, 201, 103651) by integrating evidence from a large sample of virtually reconstructed mandibles. Size and shape of maxillary dental arcades can be predicted accurately from mandibular landmarks based on strong covariation between occluding upper and lower dentitions, and a novel method was developed to correct for reduced shape variation in these predictions. As predictions are restricted to the alveolar process, morphological information about the rest of the maxilla is lost. The trade-off between a smaller sample with comprehensive morphology and a larger sample with restricted morphology is discussed. Here, we analyzed 9 original and 17 predicted A. afarensis dental arcades in the comparative context of 448 extant hominine (modern human and African ape) maxillae. This study found that (1) degrees of size and shape variation are high in A. afarensis, potentially even higher than in Gorilla species when including the predictions in the fossil sample, (2) no allometry was detected, even when expanding the A. afarensis sample with predictions, (3) size and shape do not significantly change over time when analyzing original and predicted A. afarensis dental arcades together, and (4) sexual form and shape dimorphism, but not sexual size differences, are reduced when including A. afarensis predictions in the fossil sample. 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引用次数: 0
摘要
在Hanegraef and Spoor, 2025 (the Australopithecus afarensis maxilla形态学变异)的基础上,利用几何形态计量学分析探讨了南方古猿阿法种上颌牙槽的变异。《人类进化杂志》,2011,103651),通过整合来自大量虚拟重建下颌骨样本的证据。上颌牙弓的大小和形状可以根据下颌标志准确地预测,这是基于上下牙列咬合之间的强共变,并开发了一种新的方法来纠正这些预测中减小的形状变化。由于预测仅限于牙槽突,关于上颌骨其余部分的形态学信息丢失了。讨论了具有综合形态的小样本和具有限制形态的大样本之间的权衡。在此,我们分析了9个原始的和17个预测的阿法古猿牙齿拱门,比较了448个现存的人类(现代人类和非洲猿)的上颌骨。本研究发现:(1)阿法南方古猿的大小和形状变化程度很高,如果包括化石样本中的预测,可能甚至高于大猩猩物种;(2)即使将预测的阿法南方古猿样本扩大,也没有检测到异速生长;(3)将原始和预测的阿法南方古猿牙齿拱门一起分析时,大小和形状没有随着时间的推移而显著变化;(4)性别形态和形状二态性,但没有性别大小差异。当在化石样本中包括阿法古猿预测时,减少了。我们的研究结果量化了阿法南方古猿上颌骨的变异范围和模式,为评估其他上新世-更新世古人类标本是否具有同种性提供了比较背景。
Integrating mandibular evidence to assess morphological variation of the Australopithecus afarensis maxilla.
Geometric morphometric analyses are used to explore variation of maxillary dental arcades of Australopithecus afarensis, expanding on the work of Hanegraef and Spoor, 2025 (Morphological variation of the Australopithecus afarensis maxilla. Journal of Human Evolution, 201, 103651) by integrating evidence from a large sample of virtually reconstructed mandibles. Size and shape of maxillary dental arcades can be predicted accurately from mandibular landmarks based on strong covariation between occluding upper and lower dentitions, and a novel method was developed to correct for reduced shape variation in these predictions. As predictions are restricted to the alveolar process, morphological information about the rest of the maxilla is lost. The trade-off between a smaller sample with comprehensive morphology and a larger sample with restricted morphology is discussed. Here, we analyzed 9 original and 17 predicted A. afarensis dental arcades in the comparative context of 448 extant hominine (modern human and African ape) maxillae. This study found that (1) degrees of size and shape variation are high in A. afarensis, potentially even higher than in Gorilla species when including the predictions in the fossil sample, (2) no allometry was detected, even when expanding the A. afarensis sample with predictions, (3) size and shape do not significantly change over time when analyzing original and predicted A. afarensis dental arcades together, and (4) sexual form and shape dimorphism, but not sexual size differences, are reduced when including A. afarensis predictions in the fossil sample. Our results quantifying the range and pattern of variation of the A. afarensis maxilla provide a comparative context when assessing whether or not other Plio-Pleistocene hominin specimens are conspecific.