for National Geographic News
An analysis of an ancient jaw containing teeth has confirmed that humans reached Western Europe well over a million years ago, far earlier than previously thought.
The prehistoric fossil was excavated last June at Atapuerca in northern Spain, along with a previously reported tooth and stone tools used for butchering meat.
At the time, scientists announced that they had dated the separate tooth to 1.2 million years ago but that more research was needed before the find could be reported in a scientific journal.
The new study of the jaw confirms that the "first Europeans" arrived well over a million years ago, reports the archaeological team—led by Eudald Carbonell of the Rovira i Virgili University in Tarragona, Spain—in the latest issue of the journal Nature.
The jaw's owner has been labeled a Homo antecessor—a species first named in 1997 based on other human fossils found at Atapuerca. The sex isn't known, but the new human was likely aged between 30 and 40 at the time of death.
"Since we now know those  fossils date to 900,000 [years ago], the time difference is not great, and, provisionally at least, I think it's logical to assign the mandible to Homo antecessor," said dig co-director José Maria Bermúdez de Castro of the National Research Center on Human Evolution in Burgos, Spain.
The new findings suggest that H. antecessor was most probably unique to Europe, the researchers say.
The lower jawbone was discovered inside a 60-foot-long (18-meter-long) cave known as Sima del Elefante. The region was originally exposed by a railway cutting through a limestone area rich in early hominin, or human, and animal remains.
The complex of fossils allowed scientists to use a variety of methods to confirm the age of the fossils, including magnetic analysis, radioactive dating, and geologic studies of the clustered bones and artifacts—a necessity because the dating of human fossils remains a controversial area of research.
For example, 32 stone flints also excavated from the cave date to the same age as the fossils, according to Bermúdez de Castro said.
The flints include simple tools that were likely used by the early humans to hack up mammal carcasses and get at bone marrow, as evidenced by cut marks found on nearby limb bones belonging to unidentified herbivores.
SOURCES AND RELATED WEB SITES