9月21日Science内容精选
腕骨化石意味着矮人是新物种
本期一篇报告称，三块腕骨化石是支持来自弗洛里斯岛的矮人代表一个新人种、而不是有缺陷的人的关键证据。研究人员几年来一直在争论在印度尼西亚的洞中发现的化石是否是与早期人类同时存在的一种小个的、被命名为弗洛里斯人(Homo floresiensis)的新人种。有观点认为这些化石不是新种，而是属于一个有身体缺陷的小个子的人。这些化石的年代是更新世晚期，距今12万到1万年前。Matthew W. Tocheri 和同事分析了一个编号为LB1的化石样品的三块腕骨，他们显示这些骨头比较原始，形状与人类的和尼安得特人的不同。比如，人类的小多角骨的形状象靴子，而来自LB1样品的是楔子形状的。而且LB1腕骨与非人猿的更接近。Tocheri和文章共同作者认为，这些不同意味着LB1保留了原始腕骨的特征，而现代腕骨是随着智人和尼安得特人进化出来的，所以这些化石代表这些进化出现之前的一个分支。
英文原文：
Science 21 September 2007:
Vol. 317. no. 5845, pp. 1743 - 1745
DOI: 10.1126/science.1147143
The Primitive Wrist of Homo floresiensis and Its Implications for Hominin Evolution
Matthew W. Tocheri,1* Caley M. Orr,2,3 Susan G. Larson,4 Thomas Sutikna,5 Jatmiko,5 E. Wahyu Saptomo,5 Rokus Awe Due,5 Tony Djubiantono,5 Michael J. Morwood,6 William L. Jungers4
Whether the Late Pleistocene hominin fossils from Flores, Indonesia, represent a new species, Homo floresiensis, or pathological modern humans has been debated. Analysis of three wrist bones from the holotype specimen (LB1) shows that it retains wrist morphology that is primitive for the African ape-human clade. In contrast, Neandertals and modern humans share derived wrist morphology that forms during embryogenesis, which diminishes the probability that pathology could result in the normal primitive state. This evidence indicates that LB1 is not a modern human with an undiagnosed pathology or growth defect; rather, it represents a species descended from a hominin ancestor that branched off before the origin of the clade that includes modern humans, Neandertals, and their last common ancestor.
1 Human Origins Program, Department of Anthropology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013, USA.
2 School of Human Evolution and Social Change, Arizona State University, AZ 85287, USA.
3 Institute of Human Origins, Arizona State University, AZ 85287, USA.
4 Department of Anatomical Sciences, School of Medicine, Stony Brook University, NY 11794, USA.
5 The National Research and Development Centre for Archaeology, Jakarta, Indonesia.
6 School of Earth and Environmental Sciences, University of Wollongong, NSW 2522, Australia.
* To whom correspondence should be addressed. E-mail: tocherim@si.edu
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