Edition: FINAL, Section: NEWS, pg. A1

The fossil bones and tools of Stone Age humans in Russia, and a single skull from South Africa, have provided scientists with new evidence of the routes our ancient ancestors took as they spread across continents before they reached North America, researchers report.

The findings illuminate the course of human evolutionary history from the time when the first near-modern humans appeared in sub-Saharan Africa about 190,000 years ago to the generations of today that populate the entire world.

Dug from a pit at a well-known archaeology site 250 miles from Moscow by U.S. and Russian anthropologists, the fossils and tools show for the first time that the people who migrated from Africa were fully modern humans by the time they arrived in Europe and thrived there some 45,000 years ago.

That discovery was bolstered when another international team reported that a human skull found nearly 55 years ago in a gully near the South African village of Hofmeyr came from a modern human who lived about 35,000 years ago -- not much later than the early Europeans. The skull's date, however, is expected to be controversial.

The reports by both teams are described in the journal Science being published today.

The saga of the human race and its early travels are still only dimly understood. As Ted Goebel, an anthropologist at the center for the Study of the First Americans at Texas A&M University, said, "It is one of the greatest untold stories in the history of mankind."

Part of that story has been revealed in recent years by anthropologists and archaeologists who have found the bones and tools of more recent ancient humans at many sites across Europe and central Asia.

But the tools discovered at a site called Kostenki on the Don River are the earliest ever found. The trove has been dated at 42,000 to 45,000 years old by the research team headed by Michael Anikovich and Andrei Sinitsyn of the Russian Academy of Sciences and John Hoffecker of the University of Colorado's Institute of Arctic and Alpine Research.

The tools are made of stone, animal bones and ivory and include a sewing needle with an eye, as well as a badly eroded figurine -- possibly the oldest work of art ever found, Hoffecker said.

The South African skull, its age long unknown, was newly dated by scientists at Oxford in England and the Max Planck Institute in Germany. The group was headed by Frederick Grine, an anthropologist at Stony Brook University on Long Island, who is now examining the skull anew before sending it back to colleagues in South Africa.

Genetic studies of fossil human ancestors have indicated that the first truly modern humans evolved in East Africa's great Rift Valley, roughly where Kenya and Ethiopia are now. But just when their descendants began occupying the Middle East and moved northward into Europe has remained a vexing puzzle.

The Kostenki finding for the first time places the era when modern humans reached as far north as Russia, while the African skull -- if its date is certain, and Goebel insists it is -- means that at roughly the time that modern humans made it to the bitter cold of ice age Europe and thrived there, another ancestral group must have migrated south to the tip of Africa.

In an interview Thursday, Hoffecker said the new Europeans were able to move north successfully because there is no evidence that the dead-end Neanderthal people were ever able to move there and compete for space. The Neanderthals and their tools were much more primitive, and they were unable to make the clothing or build the shelters that the Kostenki humans could.

"Culture was everything," Hoffecker said.

The Neanderthals had reached Europe long before the modern humans, but they spread primarily across southern Europe and never could compete with their more advanced and skillful human rivals. They became extinct by about 25,000 years ago.

Although doubt has been cast on the age of the South African skull dated by Grine's team, "I'm perfectly happy with the 35,000-year date," he said. He said his Oxford colleagues used a highly sophisticated new technology to measure radiation from the sand that filled the skull cavity when it was found in in 1952.

"The important thing about these results is that they are giving us new information about how fully modern humans evolved and dispersed across continents tens of thousands of years ago," Goebel said. By 40,000 or 50,000 years ago or so, he said, it appears that modern humans were thriving in Africa, across Europe and Asia and had dispersed over all the islands of southeast Asia.

Other long-accepted evidence has shown that modern humans reached Australia, perhaps as early as 40,000 years ago, while others dispersed northeastward to Siberia and from there their descendants migrated across the so-called Bering Sea land bridge into North America and California about 13,500 years ago.

E-mail David Perlman at dperlman@sfchronicle.com.

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