http://www.nytimes.com/aponline/science/AP-Oldest-Humans.html?

Oldest Remains of Modern Humans Are Identified
By THE ASSOCIATED PRESS

Published: February 16, 2005


Filed at 1:00 P.M. ET

NEW YORK (AP) -- A new analysis of bones unearthed
nearly 40 years ago in Ethiopia has pushed the fossil
record of modern humans back to nearly 200,000 years
ago -- perhaps close to the dawn of the species.

Researchers determined that the specimens are around
195,000 years old. Previously, the oldest known
fossils of Homo sapiens were Ethiopian skulls dated to
about 160,000 years ago.

Genetic studies estimate that Homo sapiens arose about
200,000 years ago, so the new research brings the
fossil record more in line with that, said John
Fleagle of Stony Brook University in New York, an
author of the study.

The fossils were found in 1967 near the Omo River in
southwestern Ethiopia. One location yielded Omo I,
which includes part of a skull plus skeletal bones.
Another site produced Omo II, which has more of a
skull but no skeletal bones. Neither specimen has a
complete face.

Although Omo II shows more primitive characteristics
than Omo I, scientists called both specimens Homo
sapiens and assigned a tentative age of 130,000 years.

Now, after visiting the discovery sites, analyzing
their geology and testing rock samples with more
modern dating techniques, Fleagle and colleagues
report in Thursday's issue of the journal Nature that
both specimens are 195,000 years old, give or take
5,000 years.

Fleagle said the more primitive traits of Omo II may
mean the two specimens came from different but
overlapping Homo sapiens populations, or that they
just represent natural variation within a single
population.

To find the age of the skulls, the researchers
determined that volcanic rock lying just below the
sediment that contained the fossils was about 196,000
years old. They then found evidence that the
fossil-bearing sediment was deposited soon after that
time.

Paul Renne, director of the Berkeley Geochronology
Center, which specializes in dating rocks, said the
researchers made "a reasonably good argument" to
support their dating of the fossils.

"It's more likely than not," he said, calling the work
"very exciting and important."

Rick Potts, director of the Human Origins Program at
the Smithsonian Institution's National Museum of
Natural History, said he considered the case for the
new fossil ages "very strong." The work suggests that
"we're right on the cusp of where the genetic evidence
says the origin of modern humans ... should be," he
said.

G. Philip Rightmire, a paleoanthropologist at
Binghamton University in New York, said he believes
the Omo fossils show Homo sapiens plus a more
primitive ancestor. The find appears to represent the
aftermath of the birth of Homo sapiens, when it was
still living alongside its ancestral species, he said.