Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK; Department of Anatomy, Faculty of Health Sciences, University of Pretoria, South Africa.
Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK; Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany; Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa.
J Hum Evol. 2022 Jun;167:103183. doi: 10.1016/j.jhevol.2022.103183. Epub 2022 Apr 21.
The calcar femorale is an internal bony structure of the proximal femur considered to be functionally related to bipedal locomotion. Among extant primates, the presence of a calcar femorale has been so far documented in extant humans and Pan and, among extinct hominins, in the Late Miocene Orrorin, in a Pliocene Australopithecus, and in a Middle Pleistocene Homo specimen. Using high-resolution microcomputed tomography, we investigated the occurrence and morphology (i.e., shape, location, and size) of the calcar femorale in an adult sample of extant humans, Pan troglodytes, Gorilla gorilla, Pongo sp., and Papio ursinus. We also investigated for the first time the occurrence and morphology of a calcar femorale in the adult proximal femoral remains of a Late Miocene great ape (Rudapithecus) and five Plio-Pleistocene hominins from Southern and Eastern Africa (Australopithecus and Paranthropus). We took four measurements: periosteal-to-tip maximum length, maximum length excluding cortical thickness, maximum vertical height, and the distance between the most anterior and posterior limits of the root. To allow for intergeneric comparisons, estimated body size was used to standardize all measurements. Nine of 10 extant humans have a well-developed calcar femorale. Among the African apes, 6 of 10 Pan and 6 of 10 Gorilla also show a distinct calcar femorale. In Pongo (n = 9), it is only present in one captive individual. None of the five investigated Papio specimens show any trace of this structure. Only calcar femorale height, which is systematically taller and extends into the lower part of the lesser trochanter, discriminates humans from extant great apes, except for one Gorilla. The calcar femorale was absent in one Paranthropus robustus and variably developed in all other investigated fossils. These results indicate that this structure cannot be considered as a diagnostic feature of habitual bipedal locomotion and emphasize the need for further investigations of its functional role.
股骨头是股骨近端的一个内部骨性结构，被认为与两足行走的功能有关。在现生灵长类动物中，目前已经在现生人类和黑猩猩中发现了股骨头，在已灭绝的人类中，在晚中新世的露西（Orrorin）、上新世的南方古猿（Australopithecus）和中更新世的人类（Homo）标本中也发现了股骨头。我们使用高分辨率微计算机断层扫描技术，研究了现生人类、黑猩猩（Pan troglodytes）、大猩猩（Gorilla gorilla）、猩猩（Pongo sp.）和狒狒（Papio ursinus）成年样本中股骨头的发生和形态（即形状、位置和大小）。我们还首次研究了晚中新世大型猿类（Rudapithecus）和来自南部和东部非洲的五个更新世人类（南方古猿和傍人）的成年股骨近端标本中股骨头的发生和形态。我们进行了四项测量：骨膜至尖端的最大长度、不包括皮质厚度的最大长度、最大垂直高度和根的最前和最后界限之间的距离。为了进行属间比较，我们使用估计的体型来标准化所有测量值。10 名现生人类中有 9 名具有发达的股骨头。在非洲猿类中，10 只黑猩猩中有 6 只和 10 只大猩猩也显示出明显的股骨头。在猩猩（n=9）中，只有一只圈养个体有。在 5 只研究狒狒标本中，没有任何这种结构的痕迹。只有股骨头高度（它系统地更高，并延伸到小转子的下部）可以将人类与现生大型猿类区分开来，除了一只大猩猩。一只傍人粗壮种（Paranthropus robustus）没有股骨头，而其他所有研究的化石中股骨头的发育程度各不相同。这些结果表明，这个结构不能被认为是习惯性两足行走的诊断特征，并强调需要进一步研究其功能作用。
