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. The discovery comprises part of a human's lower jawbone. The remains of seven teeth were found still in place; an isolated tooth, belonging to the same individual, was also unearthed. Its small size suggests it could have belonged to a female. 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 [1997] 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 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.
     The research opens an interesting new chapter in the story of European colonization, the study authors say. The earliest known human fossils found outside of Africa are from Dmanisi in the modern-day Republic of Georgia. The Georgian hominins lived some 1.7 million years ago and represent an early expansion of humans outside Africa. The researchers therefore suggest that Western Europe was settled by a population of hominins coming from the east. "This discovery shows the process was accelerated and continuous; that the occupation of Europe happened very early and much faster than we had thought," Eudald Carbonell, director of the Catalan Institute of Human Paleo-Ecology and Social Evolution, said.
     Identified as either Homo erectus or Homo ergaster, the remains date to around 1.8 million years ago. The Spanish-led team adds that the new fossil human likely marks the beginnings of a native European species represented by the younger finds at Atapuerca. "We see that these fossils are different from other populations in Asia or in Africa," Bermúdez de Castro said. The Atapuerca researchers in 1997 had suggested Homo antecessor as a possible ancestor of modern humans. But the age of the new fossil find makes this theory less likely, Bermúdez de Castro admitted. More likely, Homo antecessor gave rise to Neandertals (often spelled Neanderthals) in Europe, he said, adding, "it's a good hypothesis to test in the future."
     Fred Spoor, professor of evolutionary anatomy at University College London, said the new fossil, assuming its dating is accurate, marks "undoubtedly a very important and exciting find." While stone tools had suggested a human presence in Spain around a million years ago, convincing fossil evidence had previously been lacking, Spoor commented.

Sources: Associated Press, BBC News, National Geographic News, Time (26 March 2008), The Independent (27 March 2008)