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更新时间:2017-6-8 18:21:45 来源:纽约时报中文网 作者:佚名

Oldest Fossils of Homo Sapiens Found in Morocco, Altering History of Our Species

Fossils discovered in Morocco are the oldest known remains of Homo sapiens, scientists reported Wednesday.


Dating back roughly 300,000 years, the bones indicate that mankind evolved earlier than had been known, experts say, and open a new window on our origins.


The fossils also show that early H. sapiens had faces much like our own, although their brains differed in fundamental ways.


Until now, the oldest fossils of our species, found in Ethiopia, dated back just 195,000 years. The new fossils suggest our species evolved across Africa.


“We did not evolve from a single cradle of mankind somewhere in East Africa,” said Phillipp Gunz, a paleoanthropologist at the Max Planck Institute for Evolutionary Anthropology in Liepzig, Germany, and a co-author of two new studies on the fossils, published in the journal Nature.

“我们并非是从东非某地的唯一人类摇篮开始进化,”德国莱比锡马克斯·普朗克演化人类学研究所(Max Planck Institute for Evolutionary Anthropology)的古人类学家菲利普·贡兹(Phillipp Gunz)说。他是发表在《自然》(Nature)杂志上的两篇关于化石的新论文的联合作者。

Today, the closest living relatives to H. sapiens are chimpanzees and bonobos, with whom we share a common ancestor that lived over 6 million years ago.


After the lineages split, our ancient relatives evolved into many different species, known as hominins. For millions of years, hominins remained very ape-like. They were short, had small brains, and could fashion only crude stone tools.


Until now, the oldest fossils that clearly belonged to H. sapiens were discovered in Ethiopia. In 2003, researchers working at a site called Herto discovered a skull estimated to be between 160,000 and 154,000 years old.


A pair of partial skulls from another site, Omo-Kibish, dated to around 195,000 years of age, making these the oldest fossils of our species.


Findings such as these suggested that our species evolved in a small region — perhaps in Ethiopia, or nearby in East Africa. After H. sapiens arose, researchers believed, the species spread out across the continent.


Only much later — roughly 70,000 years ago — did a small group of Africans make their way to other continents.


Yet paleoanthropologists were aware of mysterious hominin fossils discovered in other parts of Africa that didn’t seem to fit the narrative.


In 1961, miners in Morocco dug up a few pieces of a skull at a site called Jebel Irhoud. Later digs revealed a few more bones, along with flint blades.

1961年,摩洛哥矿工在一个叫做杰贝尔依罗(Jebel Irhoud)的遗址挖出了几片头骨。后来又有几块骨骼以及火石刀片出土。

Using crude techniques, researchers estimated the remains to be 40,000 years old. In the 1980s, however, a paleoanthropologist named Jean-Jacques Hublin took a closer look at one jawbone.

研究人员借助简陋的技术方法估计,这些遗迹来自于4万年前。但在1980年代,一位名叫让-雅克·胡布灵(Jean-Jacques Hublin)的古人类学家对一块下颌骨进行了更仔细的研究。

The teeth bore some resemblance to those of living humans, but the shape seemed strangely primitive. “It did not make sense,” Hublin, now at the Max Planck Institute, recalled in an interview.


Since 2004, Hublin and his colleagues have been working through layers of rocks on a desert hillside at Jebel Irhoud. They’ve found a wealth of fossils, including skull bones from five individuals who all died around the same time.


Just as important, the scientists discovered flint blades in the same layer as the skulls. The people of Jebel Irhoud most likely made them for many purposes, putting some on wooden handles to fashion spears.


Many of the flint blades showed signs of having been burned. The people at Jebel Irhoud probably lit fires to cook food, heating discarded blades buried in the ground below. This accident of history made it possible to use the flints as clocks.


Hublin and his colleagues used a method called thermoluminescence to calculate how much time had passed since the blades were burned. They estimated that the blades were roughly 300,000 years old. The skulls, which were discovered in the same rock layer, must have been the same age.


The people of Jebel Irhoud were certainly sophisticated. They could make fires and craft complex weapons, such as wooden handled spears, needed to kill gazelle and other animals that grazed the savanna that covered the Sahara 300,000 years ago.


The flint is interesting for another reason: Researchers traced its origin to another site about 20 miles south of Jebel Irhoud. Early H. sapiens, then, knew how to search out and to use resources spread over long distances.


Similar flint blades of about the same age have been found at other sites across Africa, and scientists have long wondered who made them. The fossils at Jebel Irhoud raise the possibility that they were made by early H. sapiens.


And if that’s true, Gunz and his colleagues argue, then our species may have been evolving as a network of groups spread across the continent.


John Hawks, a paleoanthropologist at the University of Wisconsin who was not involved in the new study, said that it was a plausible idea, but that recent discoveries of fossils from the same era raise the possibility that they were used by other hominins. The only way to resolve the question will be to find more hominin fossils from the time when our species emerged.

与该项新研究无关的威斯康星大学(University of Wisconsin)古人类学家约翰·霍克斯(John Hawks)说,这是一个合理的想法,但最近发现的来自同一时代的化石,揭示了其使用者是其他古人类的可能性。解答这个问题的唯一办法是:找到来自我们物种出现之时的更多古人类化石。