July 4, 2002. Copyright 2002. Graphic News. All rights reserved. Small brains sufficient to migrate ÒOut of AfricaÓ LONDON, July 4, Graphic News: The fossil remains of what may be the earliest human ancestors to migrate from Africa into Europe have been found in the Republic of Georgia. A skull and jawbone of a small, lightly-built individual -- estimated at about 1.7 million years old -- which were unearthed during an archaeological dig at a medieval castle at Dmanisi, may call into question the prevailing idea that larger brain size was behind the migration of human ancestors out of Africa. The discovery of the fossils, found alongside stone tools and the bones of animals, is reported in the current issue of the journal Science. The team from America, Spain and Switzerland, led by David Lordkipanidze of the Georgian Academy of Sciences in Tbilisi, found a petite new individual, with a small brain, thin brow ridge, short nose, and huge canine teeth. This was the third specimen found at the site. By comparison, the other two skulls had room for substantially larger brains. Lordkipanidze and his colleagues have tentatively concluded that the three belong to the same species, Homo erectus, thought to be the first hominid species to leave Africa. The Dmanisi fossils most closely resemble the African version of Homo erectus, called Homo ergaster. ÒWe have now a very rich collection, of three skulls and three jawbones, which gives us a chance to study the question of how to classify the early hominids,Ó said Lordkipanidze. ÒThese questions are often based on isolated finds, but here we have the chance to study a population.Ó The brain of the new Dmanisi specimen was probably around 600 cubic centimetres, while modern human brains are at least twice that much, according to Lordkipanidze. The other two specimenÕs brains were approximately 800 cubic centimetres. Scientists have proposed that the evolution of larger brains was directly related to our ancestorsÕ migration out of Africa. According to this scenario, increased intelligence enabled these early humans to adapt to new environments. The new skullÕs small brain size Òsuggests that enlargement of the brain was not the only reason to leave Africa. My feeling is there should be a combination of reasons, not just one reason, that forced people out of Africa,Ó Lordkipanidze said. The new fossils also offer a rare glimpse into the diversity of a primitive human species. While we take it for granted that modern humans come in all shapes and sizes, scientists know little about individual variation among our ancestors. The skull and jawbone are unusually well-preserved, in part because a solid limestone layer overhead protected them against the usual compaction that occurs over time in sedimentary rocks. Along with the hominid fossils, the Science authors found remains of ancient species of rhinoceros, deer, wolf, horse, and sabre-toothed cat. Until the discoveries at Dmanisi, researchers generally believed that the first human species to leave Africa departed only one million years ago, and that they had large brains and relatively advanced stone tools. Dr Chris Stringer, of the Natural History Museum in London, an expert on the ÒOut of AfricaÓ theory of modern human origins, is doubtful the Dmanisi hominids were our direct ancestors. ÒThe line that these people gave rise to may have died out as recently as 50,000 years ago in the Far East,Ó he said. ÒSo it was a long-lived and successful line, but in my view a dead-end. The ancestors of modern humans may have left Africa only in the last 100,000 years.Ó /ENDS Source: Science