McHenry H M
Department of Anthropology, University of California, Davis 95616.
Proc Natl Acad Sci U S A. 1994 Jul 19;91(15):6780-6. doi: 10.1073/pnas.91.15.6780.
The quickening pace of paleontological discovery is matched by rapid developments in geochronology. These new data show that the pattern of morphological change in the hominid lineage was mosaic. Adaptations essential to bipedalism appeared early, but some locomotor features changed much later. Relative to the highly derived postcrania of the earliest hominids, the craniodental complex was quite primitive (i.e., like the reconstructed last common ancestor with the African great apes). The pattern of craniodental change among successively younger species of Hominidae implies extensive parallel evolution between at least two lineages in features related to mastication. Relative brain size increased slightly among successively younger species of Australopithecus, expanded significantly with the appearance of Homo, but within early Homo remained at about half the size of Homo sapiens for almost a million years. Many apparent trends in human evolution may actually be due to the accumulation of relatively rapid shifts in successive species.
古生物学发现步伐的加快与地质年代学的迅速发展相匹配。这些新数据表明，人类谱系中形态变化的模式是镶嵌式的。两足行走所必需的适应特征出现得较早，但一些运动特征的变化则要晚得多。相对于最早人类高度特化的颅后骨骼，颅齿复合体相当原始（即类似于与非洲大型猿类重建的最后共同祖先）。人科中相继出现的更年轻物种之间颅齿变化的模式意味着，至少在两个谱系中，与咀嚼相关的特征存在广泛的平行进化。在相继出现的更年轻的南方古猿物种中，相对脑容量略有增加，随着智人的出现显著扩大，但在早期智人中，近百万年来一直保持在约智人一半的大小。人类进化中的许多明显趋势实际上可能是由于相继物种中相对快速变化的积累。
