The functional and evolutionary implications of primitive retentions in early hominin feet have been under debate since the discovery of Australopithecus afarensis. Ontogeny can provide insight into adult phenotypes, but juvenile early hominin foot fossils are exceptionally rare. We analyze a nearly complete, 3.32-million-year-old juvenile foot of A. afarensis (DIK-1-1f). We show that juvenile A. afarensis individuals already had many of the bipedal features found in adult specimens. However, they also had medial cuneiform traits associated with increased hallucal mobility and a more gracile calcaneal tuber, which is unexpected on the basis of known adult morphologies. Selection for traits functionally associated with juvenile pedal grasping may provide a new perspective on their retention in the more terrestrial adult A. afarensis.

中文翻译：

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来自埃塞俄比亚迪基卡的近乎完整的脚，对阿法古猿的个体发育和功能具有重要意义。

自从发现南方古猿澳氏古猿以来，原始人脚早期保留的功能和进化意义一直处于争论之中。个体发育可以提供对成年表型的洞察力，但是幼小的早期人鼻足化石却极为罕见。我们分析了近完整的，332万年前的Afar afarensis（DIK-1-1f）幼足。我们显示了少年A. afarensis个人已经在成人标本中发现了许多两足动物特征。然而，他们还具有与楔形活动性增加和跟骨块茎更为柔软相关的楔形楔状中间特征，这在已知的成年形态基础上是出乎意料的。在功能上与少年踏板抓握有关的性状的选择可能为它们在陆生成虫Afarensis中的保留提供新的视角。