Holloway R L
Nature. 1983;303(5916):420-2. doi: 10.1038/303420a0.
It is rare for cerebral convolutional details to be imprinted on the internal table of cranial bone of fossil hominids. To date, the South African examples have shown the best detail, although surrounded by considerable controversy. Given that the Hadar specimens are the oldest hominids known (3-4 Myr BP), and have been the subject of considerable debate and interpretation, it is fortunate that such details are found on the cranial bones of at least one specimen, AL 162-28, a small adult. I report here a preliminary description of that endocast and it appears that despite its smallish pongid-sized brain, some degree of cerebral organization had occurred almost 3-4 Myr ago towards a more human pattern. If correct, this would mean that brain size increase may well have followed locomotion, but that brain organization may have occurred early in hominid evolution. Such a finding would call for a re-examination of our understanding about human evolution, and would require much more caution in assuming either 'gradualist' or 'punctuated equilibria' models in hominid evolution.
对于化石原始人类颅骨内板上印刻有大脑沟回细节的情况十分罕见。迄今为止，南非的例子展现出了最佳细节，尽管也引发了诸多争议。鉴于哈达尔标本是已知最古老的原始人类（距今300 - 400万年前），并且一直是大量争论和解读的对象，幸运的是在至少一个标本AL 162 - 28（一个成年小个子个体）的颅骨上发现了这样的细节。我在此报告对该脑模的初步描述，尽管其脑容量如猿类般较小，但在大约300 - 400万年前就已出现了某种程度向更具人类特征模式发展的大脑组织。如果这一结论正确，那就意味着脑容量的增加很可能是在运动能力发展之后，但大脑组织的形成可能在原始人类进化早期就已出现。这样的发现将促使我们重新审视对人类进化的理解，并且在假设原始人类进化的“渐变论”或“间断平衡论”模型时需要更加谨慎。
