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Experts Place Ancient Toolmakers on a Fast Track to Northern China
by John Noble Wilford
Bands of early human ancestors became the first intercontinental migrants sometime before 1.75 million years ago. That was when they left their skulls and stone tools near the Black Sea in Georgia, the oldest clear evidence uncovered so far of an ancestral presence outside Africa.
Now a discovery of 1.66 million-year-old stone tools in northern China has produced the earliest evidence that some of these ancestors, probably the species Homo erectus, apparently dispersed across Asia at a relatively rapid clip and made a place for themselves in a wide range of environments.
Scientists report in the current issue of the journal Nature that these ancestors, referred to as hominids or hominins, were making and using "indisputable stone tools
" at a lakeside site in upper Asia almost 340,000 years before any previously known settlement there.
Researchers were struck by the timing and latitude of the settlement in the Nihewan Basin west of Beijing. The findings at the Majuangou site, the researchers said, showed that the oldest known hominid presence in northeast Asia was "only slightly younger than that in western Asia,
" at the Dmanisi site in Georgia
Dr. Richard Potts, an anthropologist at the Smithsonian Institution's National Museum of Natural History in Washington who was co-leader of the Chinese excavations, said in an interview that the span of almost 100,000 years between the occupation of the two widely separated sites was "a drop in the bucket in terms of evolution.
Dr. Potts further noted, "Because the oldest layers show humans made tools and extracted bone marrow like early people in Africa, the Majuangou evidence suggests strong connections with African hominins and their rapid spread across Asia.
And both the Georgian and northern Chinese sites, it was noted, are located at 40 degrees north latitude, a colder, drier and more rigorous environment than the African tropics where hominids originated.
The research team suggested that the rapid migration possibly began during a phase of warm climate, which "enabled early human populations to inhabit northern latitudes of east Asia over a prolonged period.
The principal authors of the journal report were Dr. R. X. Zhu of the Institute of Geology and Geophysics in Beijing, who was responsible for dating the Chinese excavations, and Dr. Potts. They noted that the earliest artifacts of northern China were roughly comparable in age to Homo erectus fossils found in Java, in southeast Asia at 7 degrees south latitude.
Although no hominid fossils were found at the Majuangou site, Dr. Potts and others said they assumed the toolmakers were Homo erectus, one of the more immediate ancestors to modern humans.
The stone tools appeared to be used for hammering, chopping and scraping. The bones of deer- and horse-size mammals at the site indicated that they were butchered with the tools. In the colder climate with its seasonal scarcity of plant food, scientists said, meat would presumably be indispensable to the hominid diet.
Examining photographs of the tools from northern China, Dr. Philip Rightmire, a paleoanthropologist at Binghamton University in New York, said the artifacts were primitive and comparable in style and manufacture to those excavated at the Georgian site.
Dr. Rightmire is an authority on Homo erectus who is conducting research at Dmanisi but was not involved in the Chinese findings.
There seems to have been more of the Marco Polo than Thomas Edison in the travelers and settlers in north China 1.66 million years ago.
"We see little progress in toolmaking in the 100,000 years between the two sites,
" Dr. Rightmire said.