Smith Heather F, Grine Frederick E
School of Human Evolution and Social Change, Arizona State University, P.O. Box 872402, Tempe, AZ 85287-2402, United States.
J Hum Evol. 2008 May;54(5):684-704. doi: 10.1016/j.jhevol.2007.10.012. Epub 2008 Mar 4.
The phylogenetic relationships of early Pleistocene Homo crania from the South African sites of Swartkrans and Sterkfontein were investigated through cladistic analyses of 99 morphological characters. The Swartkrans Member 1 specimen SK 847 and the Stw 53 cranium from Sterkfontein Member 5A were treated as separate operational taxonomic units (OTUs), distinct from the three species of early Homo-H. erectus, H. habilis, and H. rudolfensis-that are recognized from the Plio-Pleistocene deposits of East Africa. The cladistic analyses differed in the treatment of the South African OTUs (separate Swartkrans and Sterkfontein OTUs vs. a single Swartkrans+Sterkfontein OTU). PAUP 4.0 was used to construct cladograms and address hypotheses about relationships. In the analysis that treated the South African specimens as a single OTU, the position of that OTU was stable as a separate branch on the Homo clade between H. rudolfensis and [H. habilis+(H. erectus+H. sapiens)]. When SK 847 and Stw 53 were treated as separate OTUs, the majority of most parsimonious trees indicated that they were positioned in similar positions as the combined South African Homo OTU; that is, as separate branches between H. rudolfensis and [H. habilis+(H. erectus+H. sapiens)], with the Swartkrans OTU generally occupying a more derived position. The position of the Sterkfontein OTU was more stable than that of the Swartkrans OTU, which was found in several other positions among the minimum length trees. Running the analyses with only those characters preserved by SK 847 and Stw 53 resulted in similar topologies for minimum length trees, although the positions of Stw 53, SK 847, and H. habilis exchanged places in some trees. In no case was an exclusive sister relationship between either South African OTU and a particular species of Homo supported statistically. Both South African OTUs differ from H. habilis in the fewest number of cladistic characters.
通过对99个形态特征进行分支分析，研究了来自南非斯瓦特克朗斯和斯泰克方丹遗址的早更新世人类颅骨的系统发育关系。斯瓦特克朗斯第1层的标本SK 847和斯泰克方丹第5A层的Stw 53颅骨被视为独立的操作分类单元（OTU），与从东非上新世-更新世沉积物中识别出的三种早期人类——直立人、能人和平脸人不同。分支分析在处理南非OTU时存在差异（将斯瓦特克朗斯和斯泰克方丹OTU分开处理与将斯瓦特克朗斯+斯泰克方丹作为一个单一OTU处理）。使用PAUP 4.0构建分支图并探讨有关关系的假设。在将南非标本视为单一OTU的分析中，该OTU的位置作为人属分支上鲁道夫人和[能人+（直立人+智人）]之间的一个独立分支是稳定的。当SK 847和Stw 53被视为独立的OTU时，大多数最简约树表明它们的位置与合并后的南非人属OTU相似；也就是说，作为鲁道夫人和[能人+（直立人+智人）]之间的独立分支，斯瓦特克朗斯OTU通常占据更衍生的位置。斯泰克方丹OTU的位置比斯瓦特克朗斯OTU更稳定，后者在最短长度树中出现在其他几个位置。仅使用SK 847和Stw 53保留的那些特征进行分析，得到的最短长度树拓扑结构相似，尽管在某些树中Stw 53、SK 847和能人的位置发生了交换。在任何情况下，都没有统计学上支持南非任何一个OTU与特定人类物种之间存在排他性姐妹关系。两个南非OTU与能人在最少数量的分支特征上存在差异。
