The Nesher Ramla excavation in Israel
Hershkovitz, I et al.
A previously unknown group of ancient humans lived in what is now Israel for hundreds of thousands of years. They lived alongside modern humans for some of that time, and the two groups may have interacted and learned skills from each other.
The newly discovered people were the ancestors of the Neanderthals, who later roamed Europe and western Asia, argues the team behind the work. If that is true, Neanderthals originated in western Asia, not in Europe as many researchers have previously suspected.
The hominin remains were found at Nesher Ramla in Israel, in a quarry operated by a cement factory. Following its identification, the archaeological site within the quarry was briefly protected to allow excavations to proceed in 2010 and 2011, after which it was quarried. “The site itself is gone,” says Israel Hershkovitz at Tel Aviv University in Israel, a member of the team.
Nesher Ramla was once a shallow depression in the landscape that gradually filled with sediment. “It was used by hominins for quite a long time, and it’s very rich in terms of archaeological material and very well preserved,” says Yossi Zaidner at the Hebrew University of Jerusalem, a member of the research team.
The team found parts of the roof of a hominin skull and a near-complete jawbone. “We believe it’s of the same individual,” says Hila May, also at Tel Aviv University, another author of the work.
It isn’t clear if they were male or female, because the most telltale bones are missing. “But we can say it’s a young adult based on the teeth,” says Rachel Sarig, a member of the team, also at Tel Aviv University.
The sediments in which the bones were found are between 140,000 and 120,000 years old. Our species had emerged in Africa by this time, and made some forays outside: Homo sapiens specimens from 210,000 years ago have been found in Greece, and a seemingly more sustained population existed in the Israel region from at least 177,000 years ago. But H. sapiens wasn’t the only hominin: Europe and western Asia were home to the Neanderthals (Homo neanderthalensis), while eastern Asia was home to a related group called the Denisovans.
To find out if the Nesher Ramla hominin belonged to one of these groups, the team compared the shapes of the bones with those of dozens of other hominin remains. “It was easy to say that it’s not Homo sapiens,” says May. The skull was low and flat, rather than rounded and tall, and the jawbone lacked the chin that is characteristic of our species.
But it didn’t fit any of the other groups either. In some ways, the bones resembled Neanderthal ones, but in others they looked like those of hominins that lived earlier in prehistory.
However, the Nesher Ramla bones do resemble several other hard-to-classify fossils. These include bones from the Qesem, Zuttiyeh and Tabun sites in Israel, and from Atapuerca in northern Spain, some of which are considerably older. Hershkovitz says there are also specimens from China and India that might fit.
The team argues that all these bones should be considered together as a new hominin group, which lived in western Asia between 420,000 and 120,000 years ago. The hominin at Nesher Ramla was “a residue or survivor of this source population”, argues Sarig.
The team hasn’t given the group a species name like Homo neanderthalensis, and simply calls them “Nesher Ramla Homo”. This is because the group says it doesn’t like classing hominins as distinct species if they can interbreed, so also wouldn’t count Neanderthals as a species distinct from us.
“They’re very careful not to call it a species,” says Mirjana Roksandic at the University of Winnipeg in Manitoba, Canada. She says that requires “more discussion”.
The Neanderthal-like features of Nesher Ramla Homo can be explained if they were the ancestors of the Neanderthals, the team argues. On this account, the usual story of the origin of the Neanderthals – that they evolved from earlier European hominins – is wrong. Instead, they originated in western Asia as a subgroup of Nesher Ramla Homo, and entered Europe only when the climate was favourable.
Roksandic is intrigued but not convinced. “These morphological traits of Neanderthals that they see could be easily interpreted as the movement of Neanderthals back,” she says – in which case, Nesher Ramla Homo may have picked them up from Neanderthals, rather than the other way around.
However, May thinks the research team’s scenario makes more sense. Moreover, it would explain a mystery. A Neanderthal who lived in northern Europe 124,000 years ago had some H. sapiens DNA, around 80,000 years before modern humans got there. This could be explained if modern humans interbred with Nesher Ramla Homo in western Asia and some of the resulting hybrids interbred with European Neanderthals.
The Nesher Ramla Homo may also explain other unusual fossils. The bones from the caves of Skhul and Qafzeh in Israel have sometimes been classed as H. sapiens, but don’t look typical of our species. The team suggests they are actually the result of interbreeding between H. sapiens and Nesher Ramla Homo.
There is clear evidence that Nesher Ramla Homo and H. sapiens were interacting, says Zaidner. They made very similar tools, using exactly the same process. This suggests that one group learned the skills from the other. But “we don’t know… who learned from who.”
Journal references: Science, DOI: 10.1126/science.abh3169 and DOI: 10.1126/science.abh3020
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Source: Humans - newscientist.com
