Williams Scott A, García-Martínez Daniel, Bastir Markus, Meyer Marc R, Nalla Shahed, Hawks John, Schmid Peter, Churchill Steven E, Berger Lee R
Center for the Study of Human Origins, Department of Anthropology, New York University, 25 Waverly Place, New York, NY 10003, USA; Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa; New York Consortium in Evolutionary Primatology, New York, NY 10024, USA.
Paleoanthropology Group, Museo Nacional de Ciencias Naturales (MNCN-CSIC), J.G. Abascal 6, 28006 Madrid, Spain; Faculty of Sciences, Biology Department, Universidad Autónoma de Madrid, 28049 Madrid, Spain; Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa.
J Hum Evol. 2017 Mar;104:136-154. doi: 10.1016/j.jhevol.2016.11.003. Epub 2017 Jan 13.
Hominin evolution featured shifts from a trunk shape suitable for climbing and housing a large gut to a trunk adapted to bipedalism and higher quality diets. Our knowledge regarding the tempo, mode, and context in which these derived traits evolved has been limited, based largely on a small-bodied Australopithecus partial skeleton (A.L. 288-1; "Lucy") and a juvenile Homo erectus skeleton (KNM-WT 15000; "Turkana Boy"). Two recent discoveries, of a large-bodied Australopithecus afarensis (KSD-VP-1/1) and two Australopithecus sediba partial skeletons (MH1 and MH2), have added to our understanding of thorax evolution; however, little is known about thorax morphology in early Homo. Here we describe hominin vertebrae, ribs, and sternal remains from the Dinaledi chamber of the Rising Star cave system attributed to Homo naledi. Although the remains are highly fragmented, the best-preserved specimens-two lower thoracic vertebrae and a lower rib-were found in association and belong to a small-bodied individual. A second lower rib may belong to this individual as well. All four of these individual elements are amongst the smallest known in the hominin fossil record. H. naledi is characterized by robust, relatively uncurved lower ribs and a relatively large spinal canal. We expect that the recovery of additional material from Rising Star Cave will clarify the nature of these traits and shed light on H. naledi functional morphology and phylogeny.
人族的进化特点是从适合攀爬和容纳大肠道的躯干形态，转变为适应双足行走和更高质量饮食的躯干形态。我们对这些衍生特征进化的节奏、模式和背景的了解一直有限，这主要基于一具小个子南方古猿的部分骨骼（A.L. 288 - 1；“露西”）和一具直立人少年的骨骼（KNM - WT 15000；“图尔卡纳男孩”）。最近两项发现，一具大体型的阿法南方古猿（KSD - VP - 1/1）和两具南方古猿源泉种的部分骨骼（MH1和MH2），增进了我们对胸廓进化的理解；然而，对于早期人类的胸廓形态却知之甚少。在此，我们描述了来自新星洞穴系统迪纳莱迪洞穴的人族椎骨、肋骨和胸骨遗骸，这些遗骸被归为纳莱迪人。尽管遗骸高度破碎，但保存最完好的标本——两枚下胸椎和一根下肋骨——是关联发现的，且属于一个小个子个体。另一根下肋骨可能也属于这个个体。这四块单独的骨骼都是人族化石记录中已知最小的。纳莱迪人具有粗壮、相对不弯曲的下肋骨和相对较大的椎管的特征。我们预计，从新星洞穴中获取更多材料将阐明这些特征的本质，并揭示纳莱迪人的功能形态和系统发育情况。
