Univ. Bordeaux, CNRS, MCC, PACEA, UMR 5199, F-33600 Pessac, France.
Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany.
Proc Natl Acad Sci U S A. 2022 Jul 12;119(28):e2111212119. doi: 10.1073/pnas.2111212119. Epub 2022 Jul 5.
The origins of , as well as the diversity and biogeographic distribution of early species, remain critical outstanding issues in paleoanthropology. Debates about the recognition of early , first appearance dates, and taxonomic diversity within are particularly important for determining the role that southern African taxa may have played in the origins of the genus. The correct identification of remains also has implications for reconstructing phylogenetic relationships between species of and , and the links between early species and . We use microcomputed tomography and landmark-free deformation-based three-dimensional geometric morphometrics to extract taxonomically informative data from the internal structure of postcanine teeth attributed to Early Pleistocene in the southern African hominin-bearing sites of Sterkfontein, Swartkrans, Drimolen, and Kromdraai B. Our results indicate that, from our sample of 23 specimens, only 4 are unambiguously attributed to , 3 of them coming from Swartkrans member 1 (SK 27, SK 847, and SKX 21204) and 1 from Sterkfontein (Sts 9). Three other specimens from Sterkfontein (StW 80 and 81, SE 1508, and StW 669) approximate the condition in terms of overall enamel-dentine junction shape, but retain -like dental traits, and their generic status remains unclear. The other specimens, including SK 15, present a dominant australopith dental signature. In light of these results, previous dietary and ecological interpretations can be reevaluated, showing that the geochemical signal of one tooth from Kromdraai (KB 5223) and two from Swartkrans (SK 96 and SKX 268) is consistent with that of australopiths.
早期人属物种的起源、多样性和生物地理分布仍然是古人类学中关键的未解决问题。关于早期人属的识别、首次出现的日期以及其内部的分类多样性的争论，对于确定南部非洲分类单元在人属起源中可能发挥的作用尤为重要。正确识别人属遗骸也对重建人属和南方古猿属物种之间的系统发育关系以及早期人属物种与南方古猿属的联系具有重要意义。我们使用微计算机断层扫描和无地标变形的三维几何形态测量学，从斯特克方丹、斯瓦特克朗斯、德雷莫伦和克罗姆德莱 B 的南部非洲古人类化石遗址中归因于早更新世的后犬齿的内部结构中提取分类学信息数据。我们的结果表明，在我们的 23 个样本中，只有 4 个明确地属于南方古猿粗壮种，其中 3 个来自斯瓦特克朗斯组 1（SK 27、SK 847 和 SKX 21204），1 个来自斯特克方丹（Sts 9）。另外 3 个来自斯特克方丹的标本（StW 80 和 81、SE 1508 和 StW 669）在整体釉牙骨质界形状方面接近南方古猿粗壮种的情况，但保留了南方古猿纤细种的牙齿特征，其属种地位仍不清楚。其他标本，包括 SK 15，表现出明显的南方古猿牙齿特征。鉴于这些结果，可以重新评估先前的饮食和生态解释，表明来自克罗姆德莱的一颗牙齿（KB 5223）和来自斯瓦特克朗斯的两颗牙齿（SK 96 和 SKX 268）的地球化学信号与人属一致。
