Late Miocene hominids from the Middle Awash, Ethiopia
Late Miocene hominids from the Middle Awash, Ethiopia
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DOI：
10.1038/35084063
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发表时间：
2001-07-12
期刊：
影响因子：
64.8
通讯作者：
Haile-Selassie, Y
中科院分区：
文献类型：
--
作者：
Haile-Selassie, Y
分子研究表明，人类和黑猩猩的谱系在大约650 - 550万年前（Myr）的中新世晚期（1-3）分化。然而，这一时期的人科化石是残缺不全的，其系统发育地位、年龄或两者都不确定（4-6）。在这里，我报告了来自埃塞俄比亚中阿瓦什地区的新人科标本，其时间可追溯到520万至580万年，与树木繁茂的古环境有关（7）。这些晚中新世的化石被归为原始人属地猿，代表了原始人分支的最早的明确证据。衍生的牙齿特征只与所有较年轻的原始人类共享。这表明，这些化石可能代表了一个原始人类分类单元，其时间要晚于导致现代黑猩猩和人类的谱系分歧。然而，这些新化石中原始的牙齿和颅后特征的持续存在表明，地猿与黑猩猩和人类的共同祖先在遗传学上很接近。这些新的发现对图根奥罗林人（Orrorin tugenensis）（8）的原始人类地位提出了更多的问题，图根奥罗林人最近在肯尼亚被描述，可追溯到大约600万年前（9）。
Molecular studies suggest that the lineages leading to humans and chimpanzees diverged approximately 6.5-5.5 million years (Myr) ago, in the Late Miocene(1-3). Hominid fossils from this interval, however, are fragmentary and of uncertain phylogenetic status, age, or both(4-6). Here I report new hominid specimens from the Middle Awash area of Ethiopia that date to 5.2-5.8 Myr and are associated with a wooded palaeoenvironment(7). These Late Miocene fossils are assigned to the hominid genus Ardipithecus and represent the earliest definitive evidence of the hominid clade. Derived dental characters are shared exclusively with all younger hominids. This indicates that the fossils probably represent a hominid taxon that postdated the divergence of lineages leading to modern chimpanzees and humans. However, the persistence of primitive dental and postcranial characters in these new fossils indicates that Ardipithecus was phylogenetically close to the common ancestor of chimpanzees and humans. These new findings raise additional questions about the claimed hominid status of Orrorin tugenensis(8), recently described from Kenya and dated to similar to6 Myr(9).