Humans made early European entry.

An excavation in an underground cavern in northern Spain has yielded fossils and stone tools from human ancestors who inhabited the region at least 780,000 years ago, according to a new report. If that age estimate holds up, the discovery shows that the human colonization of Europe began about 300,000 years earlier than many researchers had assumed.

"The settlement of Western Europe probably occurred. . .at an early time in the evolution of the genus Homo," conclude Eudald Carbonell of the University of Roviri and Virgili in Tarragona, Spain, and his colleagues.

Beginning perhaps 1 million years ago, a succession of related Homo species, including Neandertals, evolved in Europe, the Spanish scientists assert. This European lineage eventually died out and was replaced by modern-looking humans who originated in Africa, they theorize.

Carbonell's group presents its findings in the Aug. 11 Science, along with a report on paleomagnetic dating of the site directed by Josep M. Pares of the University of Michigan in Ann Arbor.

"If the dating of the site is accurate, this is a fantastic discovery," asserts John J. Shea of the State University of New York at Stony Brook. "But the paleomagnetic dates need to be confirmed by a radiometric dating method."

The specimens come from a limestone cavern, called Gran Dolina, in Spain's Atapuerca Mountains. Exploration of a nearby cave has already produced 300,000-year-old Neandertal remains (SN: 4/10/93, p.228). The Gran Dolina project has unearthed 100 stone implements and 36 hominid bone fragments. Most stone artifacts had been chipped off larger stones and sharpened on one side, a rudimentary tool-making technique.

The fossils come from at least four individuals and consist largely of teeth, jaws, and parts of the braincase.

Comparison of the shape and size of the bones to those of other hominid specimens indicates that the Spanish site was inhabited either by an early form of H. heidelbergensis, a species already assigned to a 500,000-year-old German jaw, or a new and as yet unnamed Homo species, Carbonell's team contends.

Reversed polarity of the magnetic field in Gran Dolina's fossil- and artifact-bearing sediment places the finds at a minimum of 780,000 years old. They may date to as early as 1 million years ago, according to Pares, who plans to conduct further geological testing at the site in October.

"They've hit the jackpot with this new find," asserts F. Clark Howell of the University of California, Berkeley, who has visited the Spanish site and seen the hominid discoveries. Until now, he notes, many scientists thought that human ancestors lived on the Asian fringes of Europe for more than 1 million years before heading west about 500,000 years ago (SN: 2/11/95, p.85).

Both Howell and Shea suspect that rather than staying put, as the Spanish researchers propose, hominids filtered into and out of Europe between periods of extreme cold, beginning around 1 million years ago. Hominids that migrated from Africa later, not those at Gran Dolina, may have served as Neandertal ancestors, Howell proposes.