Bastir Markus, García-Martínez Daniel, Estalrrich Almudena, García-Tabernero Antonio, Huguet Rosa, Ríos Luis, Barash Alon, Recheis Wolfgang, de la Rasilla Marco, Rosas Antonio
Paleoanthropology Group, Museo Nacional de Ciencias Naturales (CSIC), J. G. Abascal 2, 28006, Madrid, Spain.
Paleoanthropology Group, Museo Nacional de Ciencias Naturales (CSIC), J. G. Abascal 2, 28006, Madrid, Spain.
J Hum Evol. 2015 Mar;80:64-73. doi: 10.1016/j.jhevol.2014.10.008. Epub 2015 Jan 3.
Reconstructing the morphology of the Neanderthal rib cage not only provides information about the general evolution of human body shape but also aids understanding of functional anatomy and energetics. Despite this paleobiological importance there is still debate about the nature and extent of variations in the size and shape of the Neandertal thorax. The El Sidrón Neandertals can be used to contribute to this debate, providing new costal remains ranging from fully preserved and undistorted ribs to highly fragmented elements. Six first ribs are particularly well preserved and offer the opportunity to analyze thorax morphology in Neandertals. The aims of this paper are to present this new material, to compare the ontogenetic trajectories of the first ribs between Neandertals and modern humans, and, using geometric morphometrics, to test the hypothesis of morphological integration between the first rib and overall thorax morphology. The first ribs of the El Sidrón adult Neandertals are smaller in centroid size and tend to be less curved when compared with those of modern humans, but are similar to Kebara 2. Our results further show that the straightening of the first ribs is significantly correlated with a straightening of the ribs of the upper thorax (R = 0.66; p < 0.0001) in modern humans, suggesting modularity in the upper and lower thorax units as reported in other hominins. It also supports the hypothesis that the upper thorax of Neandertals differs in shape from modern humans with more anteriorly projecting upper ribs during inspiration. These differences could have biomechanical consequences and account for stronger muscle attachments in Neandertals. Different upper thorax shape would also imply a different spatial arrangement of the shoulder girdle and articulation with the humerus (torsion) and its connection to the upper thorax. Future research should address these inferences in the context of Neandertal overall body morphology.
重建尼安德特人的肋骨形态不仅能提供有关人类体型总体进化的信息,还有助于理解功能解剖学和能量学。尽管具有这种古生物学重要性,但关于尼安德特人胸廓大小和形状的变异性质及程度仍存在争议。埃尔西龙(El Sidrón)的尼安德特人可为此争论提供帮助,他们提供了新的肋骨残骸,范围从保存完好且未变形的肋骨到高度破碎的骨骼。六根第一肋骨保存得特别完好,为分析尼安德特人的胸廓形态提供了机会。本文的目的是展示这些新材料,比较尼安德特人和现代人类第一肋骨的个体发育轨迹,并使用几何形态测量学来检验第一肋骨与整体胸廓形态之间形态整合的假设。与现代人类相比,埃尔西龙成年尼安德特人的第一肋骨在质心大小上较小,且弯曲度往往较小,但与凯巴拉2号(Kebara 2)相似。我们的结果进一步表明,在现代人类中,第一肋骨的变直与上胸部肋骨的变直显著相关(R = 0.66;p < 0.0001),这表明上胸部和下胸部单元具有模块化,正如在其他古人类中所报道的那样。这也支持了这样的假设,即尼安德特人的上胸部形状与现代人类不同,在吸气时上肋骨更向前突出。这些差异可能会产生生物力学后果,并解释尼安德特人更强的肌肉附着情况。不同的上胸部形状也意味着肩带的空间排列不同,以及与肱骨的关节连接(扭转)及其与上胸部的连接不同。未来的研究应在尼安德特人整体身体形态的背景下探讨这些推断。