Anderson Sophia C, Kovarovic Kris, Barr W Andrew
Department of Archaeology, University of York, York, UK.
Department of Anthropology, Durham University, Durham, UK.
J Anat. 2024 Sep;245(3):451-466. doi: 10.1111/joa.14062. Epub 2024 May 11.
The family Bovidae [Mammalia: Artiodactyla] is speciose and has extant representatives on every continent, forming key components of mammal communities. For these reasons, bovids are ideal candidates for studies of ecomorphology. In particular, the morphology of the bovid humerus has been identified as highly related to functional variables such as body mass and habitat. This study investigates the functional morphology of the bovid distal humerus in isolation due to its increased likelihood of preservation in the fossil record, and the resulting opportunity for a better understanding of the ecomorphology of extinct bovids. A landmark scheme of 30 landmarks was used to capture the 3D distal humerus morphology in 111 extant bovid specimens. We find that the distal humerus has identifiable morphologies associated with body mass, habitat preference and tribe affiliation and that some characteristics are shared between high body mass bovids and those living on hard, flat terrain which is likely due to the high stress on the bone in both cases. We directly apply our findings regarding extant bovids to the extinct alcelaphine bovid, Rusingoryx atopocranion from the mid to late Pleistocene (>33-45 ka) Lake Victoria region of Kenya. This species is known for some peculiar morphologies including a domed cranium with hollow nasal crests, and having small hooves for a bovid of its size. Another interesting aspect of Rusingoryx's skeletal morphology which has not been addressed is an unusual protrusion on the lateral epicondyle of the distal humerus. Despite considerable individual variation in the Rusingoryx specimens, we find evidence to support its historical assignment to the tribe Alcelaphini, and that it likely preferred open grassland habitats, which is consistent with independent reconstructions of the palaeoenvironment. We also provide the most accurate body mass estimate for Rusingoryx to date, based on distal humerus centroid size. Overall, we are able to conclude that the distal humerus in extant bovids is highly informative regarding body mass, habitat preference and tribe, and that this can be applied directly to a fossil taxon with promising results.
牛科动物[哺乳纲：偶蹄目]种类繁多，在各大洲均有现存代表物种，是哺乳动物群落的关键组成部分。基于这些原因，牛科动物是生态形态学研究的理想对象。特别是，牛科动物肱骨的形态已被确定与体重和栖息地等功能变量高度相关。由于其在化石记录中保存的可能性增加，以及由此带来的更好地了解已灭绝牛科动物生态形态的机会，本研究单独调查了牛科动物远端肱骨的功能形态。使用一个包含30个地标点的地标方案来捕捉111个现存牛科动物标本的三维远端肱骨形态。我们发现，远端肱骨具有与体重、栖息地偏好和族属相关的可识别形态，并且一些特征在高体重牛科动物和生活在坚硬平坦地形上的牛科动物之间共享，这可能是由于在这两种情况下骨骼承受的高压力所致。我们将关于现存牛科动物的研究结果直接应用于已灭绝的狷羚亚科牛科动物——来自肯尼亚中更新世至晚更新世（>33 - 45 ka）维多利亚湖地区的头顶圆隆狷羚。该物种以一些独特的形态而闻名，包括一个有中空鼻嵴的圆顶颅骨，以及相对于其体型而言较小的蹄子。头顶圆隆狷羚骨骼形态的另一个有趣方面尚未得到探讨，即远端肱骨外侧髁上有一个不寻常的突出物。尽管头顶圆隆狷羚标本存在相当大的个体差异，但我们发现有证据支持其历史上被归为狷羚族，并且它可能更喜欢开阔的草原栖息地，这与古环境的独立重建结果一致。我们还基于远端肱骨质心大小提供了迄今为止最准确的头顶圆隆狷羚体重估计值。总体而言，我们能够得出结论，现存牛科动物的远端肱骨在体重、栖息地偏好和族属方面具有很高的信息价值，并且这可以直接应用于化石分类单元，取得了有前景的结果。
