A startlingly humanlike cache of fossils from a Spanish cave is rewriting the early history of Europe. The fossils represent a new species of proto-humans that push back the occupation of Europe by more than 300,000 years, changing anthropologists’ notions about exactly who migrated out of Africa into the rest of the world.
The 800,000-year-old fossils, which represent the last common ancestor of modern humans and the Neanderthals who fluorished throughout early Europe, bear facial characteristics commonly seen only in much more recent fossils.
The finding, reported in Thursday’s edition of the British journal Nature by a team from the National Museum of Natural History in Madrid, Spain, is but the latest in a series of discoveries suggesting that the human family tree looks more like an oak than a palm, sprouting large numbers of branches that withered in evolutionary dead ends.
“It’s clear that the Spanish team is on to something pretty important,” said paleoanthropologist Philip Rightmire of the State University of New York at Binghamtom. “They’ve got a wealth of material, and it is all dated securely to 800,000 years ago. That’s the earliest human remains from anywhere in Europe.”
“We believe that this is a new species that we have called ‘Homo antecessor’,” from the Latin word meaning an explorer or one who goes first, said paleobiologist Jose Maria Bermudez de Castro of the National Museum of Natural Sciences in Madrid, lead author of the report. “It’s a species that we consider the common ancestor of modern humanity and the Neanderthals.”
The new fossils “give us an idea of the amazing variation in (human ancestors),” said paleoanthropologist Jean-Jacques Hublin of the National Center for Scientific Research in Paris.
Although some researchers question whether the fossils are indeed a new species, their unquestioned antiquity is certain to provoke much discussion about the dissemination of hominids - the scientific term for two-legged mammals - from their first home in Africa.
Hominids are commonly believed to have started spreading outwards from Africa as long as 1.8 million years ago. But no bones older than 500,000 years have previously been found anywhere in Europe.
Bermudez and his colleagues made their discovery at a site called Gran Dolino in the reddish Atapuerco hills of northern Spain. There, railroad workers blasting a tunnel in the late 19th century exposed cross sections of bone-filled limestone caverns. Different layers date from as recent as 170,000 years ago to as old as 800,000 years ago.
Excavating in the deepest, oldest layer, the team found more than 80 fossils, including skulls, jaws, teeth, and other bones, from six individuals. The centerpiece of the collection was the youth’s skull, particularly its mid-facial region.
That face had such modern features as sunken cheekbones, a horizontal ridge where the teeth attach rather than the vertical ridge found in earlier species, and a projecting mid-face and nose.
Not everyone agrees that the material represents a distinct new species, however. Rightmire cautions that the only facial bones are from a young boy, probably 11 or 12 years old. Skulls from the young often change as the individual ages, he noted. “It’s always tricky to compare children to adults,” he added.
Counterbalancing those modern characteristics, however, were a prominent brow ridge like that of the Neanderthals and the multiple roots for premolar teeth characteristic of early hominids. The Spanish team concluded that this unusual mix of traits was unique, justifying the need for a new species classification.
The team noted that H. antecessor was heavyset, about average height and had a brain capacity of about 1,000 cubic centimeters, considerably smaller than modern humans.
Exactly where H. antecessor fits into the chain of human evolution is the subject of some argument, however.
Up until about 10 years ago, that chain was thought to proceed , step-by-step, from “Homo habilis,” the tool-maker, through “Homo erectus,” who stood upright on the plains of Africa, to archaic “Homo sapiens,” the direct ancestor of both Neanderthals and modern humans.
But new fossil discoveries and more sophisticated analyses of old ones have revealed a much greater complexity.