In 1938, the first distal femur of a fossil Australopithecus was discovered at Sterkfontein, South Africa. A decade later, another distal femur was discovered at the same locality. These two fossil femora were the subject of a foundational paper authored by Kingsbury Heiple and Owen Lovejoy in 1971. In this paper, the authors discussed functionally relevant anatomies of these two fossil femora and noted their strong affinity to the modern human condition. Here, we update this work by including eight more fossil Australopithecus distal femora, an expanded comparative dataset, as well as additional linear measurements. Just as Heiple and Lovejoy reported a half-century ago, we find strong overlap between modern humans and cercopithecoids, except for inferiorly flattened condyles and a high bicondylar angle, both of which characterize modern humans and Australopithecus and are directly related to striding bipedalism. All other measured aspects of the femora are by-products of these key morphological traits. Additional fossil material from the early Pliocene will help to inform the evolution of the hominin distal femur and its condition in the Pan-Homo common ancestor that preceded bipedal locomotion.

中文翻译：

---

南方古猿股骨远端的研究进展

1938 年，在南非斯泰克方丹发现了第一块南方古猿股骨远端化石。十年后，在同一地点发现了另一个股骨远端。这两个股骨化石是 Kingsbury Heiple 和 Owen Lovejoy 于 1971 年撰写的基础论文的主题。在这篇论文中，作者讨论了这两个股骨化石的功能相关解剖结构，并指出它们与现代人类状况的密切关系。在这里，我们更新了这项工作，包括另外八个南方古猿股骨远端化石、扩展的比较数据集以及额外的线性测量。正如Heiple和Lovejoy在半个世纪前报道的那样，我们发现现代人类和鹿类动物之间有很强的重叠性，除了下扁平的髁突和高的双髁角，这两者都是现代人类和南方古猿的特征，并且与跨步两足行走直接相关。股骨的所有其他测量方面都是这些关键形态特征的副产品。来自上新世早期的更多化石材料将有助于了解古人类股骨远端的进化及其在双足运动之前的泛人类共同祖先中的状况。