Jaw-dropping find emerges from Stone Age cave. (European Ancestors).

Researchers exploring a Romanian cave system in March 2002 got a prehistoric surprise. The scientists, directed by Oana Moldovan of the Romanian Academy in Cluj, swam through an underwater passageway and entered a largely dry, limestone chamber. In the middle of this cave, resting on the ground, lay a nearly complete lower jaw that may represent the oldest known example of anatomically modern Homo sapiens in Europe.

Preliminary radiocarbon analyses of the jaw indicate that it's at least 35,200 years old, says Erik Trinkaus of Washington University in St. Louis, who is collaborating with the Romanian team. Ongoing radiocarbon tests may reduce that age estimate slightly, according to Trinkaus.

Still, in his view, the jaw is the first clear fossil evidence that people inhabited southeastern Europe by around 35,000 years ago. If the date holds up, it bolsters the theory that modern H. sapiens initially spread from Africa and the Middle East into eastern Europe and then moved westward.

Although the jaw's shape generally corresponds to that of later H. sapiens, it bears a few Neandertal traits, Trinkaus adds. These include exceptionally broad swaths of bone running up the back of the mouth and large tooth crowns.

Investigators of Romania's so-called Cave with Bones have also discovered skeletal remains of extinct cave bears and wild goats. These bones show no signs of human hunting or violent death. However, several bear skulls were on large rocks, as has been found in a Stone Age cave in France. "Someone was apparently rearranging the bones in the past," Trinkaus says.