Sunday, August 14, 2011

Challenges to the "Out of Africa" Theory of Human Evolution/Migration Continue

Here's the lastest in the ongoing battle:

Caveman Zezva’s 1.8-Million-Year Grin Forces Rewrite of History
By Helena Bedwell - Aug 8, 2011 6:00 PM CT

The history of human evolution needs to be rewritten.

This is the view of David Lordkipanidze, who claims his discovery of the bones of a couple known as Zezva and Mzia puts the Black Sea country of Georgia at the center of the archaeological world.

The small-brained apelike creatures lived in the area at least 1.75 million years ago, making them the first proven residents of Europe and Asia, says Lordkipanidze. The find has thrown into question the theory that the first hominids to disperse from Africa were homo erectus, a species with large brains and bodies approaching human size.

“Now the news is that we have found stone tools,” says Lordkipanidze, the Georgian National Museum’s director. “Stone and bone samples are older than any other findings, proving we’ve had human presence in Georgia from at least 1.85 million years or more.”

The 49-year-old professor remains calm about the discovery, sitting in his office wearing a blue shirt and denims. The news is supported by 10 experts who have written a report to the National Academy of Science, he says. Lordkipanidze is also dismissive of skeptics who say the announcement is only intended to help Georgia to become a bigger tourist destination and global hub for archaeology.

The nation of 4.6 million people on the Silk Road has been trying to restore its economy after it fought a five-day war in 2008 over the breakaway Georgian region of South Ossetia. The Georgian government forecasts as many as 3 million tourist visits this year, rising to 5 million by 2015.

Human Jaw

Lordkipanidze’s room is bright and modest. Shelves are full of memorabilia of the findings from near the village of Dmanisi, southwest of the capital Tbilisi and near the Armenian border.

An international team found the first human jaw there in 1991. Between then and 2007, fossils from as many as six individuals have been found at the same site. Three are being reconstructed by artists -- Zezva and Mzia (typical old- fashioned Georgian names) and their possible offspring of a teenage female. The skulls can be covered with flesh and hair to give them simian smiles and protruding jaws. The excavations are funded by Georgia’s government and companies including BP Plc and Rolex Group.

National Geographic magazine, and Science, have both put Zezva and Mzia on their covers, noting that they hold the key to human evolution. Perhaps early humans took a detour into Eurasia before an epic journey out of Africa.

“Dmanisi humans are either the first representatives of homo erectus,” says Lordkipanidze. “Or ancestors of homo erectus.”

Tiger Skulls

These people were about 1.4 meters (4 feet 9 inches) tall, with small brains and legs more developed than their arms, showing that they were good runners. They lived alongside predators like saber-toothed tigers, whose skulls were also found.

“Their main lifestyle was to compete with big and dangerous animals,” Lordkipanidze says. “They lived in groups and they were taking care of each other.” They were on a site totaling no more than 10 square meters and their death was mostly natural.

Lordkipanidze’s museum’s collection dates back to 1852. After the Rose revolution in 2003, it was re-established the following year by a presidential decree. It unifies the Soviet Occupation Museum, the archives of the Ministry of State Security and Internal Affairs of Georgia, and the golden treasury, including objects from the ancient kingdom of Colchis from Vani, known as the destination of Jason and the Argonauts in their quest for the Golden Fleece.

Excavations continue at Dmanisi, while only 10 percent of the historical site has been explored, Lordkipanidze says.

“The world should know that we are preserving a world heritage, not just ours,” Lordkipanidze says. “It’s highly educational and has huge tourism potential.”


And this - not exactly related but it only goes to show that we have a lot yet to learn about what happened 50,000 to 40,000 years ago, let alone a couple of million years ago!

Stone Age toe could redraw human family tree
10 August 2011 by Colin Barras
Magazine issue 2825.

ON THE western fringes of Siberia, the Stone Age Denisova cave has surrendered precious treasure: a toe bone that could shed light on early humans' promiscuous relations with their hominin cousins.

New Scientist has learned that the bone is now in the care of Svante Pääbo at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who revealed the first genetic evidence of interbreeding between ancient humans and other hominins (New Scientist, 30 July, p 34).

There are tantalising hints that the find strengthens the case for a third major group of hominins circulating in Eurasia at the same time as early humans and the Neanderthals. It might possibly even prove all three groups were interbreeding (see diagram).

The Denisova cave had already yielded a fossil tooth and finger bone, in 2000 and 2008. Last year, Pääbo's DNA analysis suggested both belonged to a previously unknown group of hominins, the Denisovans. The new bone, an extremely rare find, looks likely to belong to the same group.

It is a very exciting discovery, says Isabelle De Groote at London's Natural History Museum. "Hominin material from southern Siberia is rare and usually extremely fragmentary."

The primitive morphology of the 30,000 to 50,000-year-old Denisovan finger bone and tooth indicates that Denisovans separated from the Neanderthals roughly 300,000 years ago. At the time of the analysis, Pääbo speculated that they came to occupy large parts of east Asia at a time when Europe and western Asia were dominated by Neanderthals. By 40,000 years ago, Homo sapiens was also moving around much of the region. But the Denisovans remain known only from the finger and tooth fossils - not enough information to formally assign them to their own species.

That may change with analysis of the newly discovered toe bone. It was found in the same layer of the cave floor as the finger bone, by Maria Mednikova at the Russian Academy of Sciences in Moscow (Archaeology, Ethnology and Anthropology of Eurasia, vol 39, p 129).

Mednikova says this suggests it belonged to a contemporary individual, alive roughly 40,000 years ago. But her studies show the finger and toe bones belonged to distinct people. In addition, the toe bone is stocky and its shape is somewhere between that of a modern human and a typical Neanderthal.

Others are less convinced. Erik Trinkaus at Washington University in St Louis, Missouri, who has written extensively on hominin foot bone morphology, says the bone's sturdy appearance is interesting but inconclusive from a taxonomic perspective.

What's needed is DNA evidence. For now, though, Pääbo's team remain very tight-lipped about what, if anything, they have found. "We have no results we are ready to talk about yet," Pääbo told New Scientist. Mednikova saw some of the team's preliminary findings last month and promises a "wonderful result" will be published in the near future - although with the analysis still under review she can say no more.

Her enthusiasm suggests that Pääbo's team has successfully extracted DNA from the toe bone, and hints that it shows that this was no ordinary hominin. At the very least, one can presume it doesn't belong to a human or a Neanderthal.

"The Neanderthals came to the Altai mountains [in Siberia] about 45,000 years ago and were probably assimilated by the native Denisovan population," she says. "It cannot be excluded that the individual was Denisovan, Neanderthal or even a hybrid - why not?"

If the Stone Age toe really did belong to a Neanderthal-Denisovan hybrid, it would be a remarkable find. Pääbo is fast building a reputation for revealing Homo sapiens' promiscuous past. He has shown that humans and Neanderthals interbred, as did humans and Denisovans. Until the latest analysis is published, we can only speculate on what has been found. But the human family tree could be about to get even more complicated. If so, there may be a case for reclassifying all three as members of the same species.

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