Cutting-edge technology. A stone core (lower left) and three of the recently found blades. Credit: Cara Roure Johnson and Sally McBrearty/University of ConnecticutScience Now:
CHICAGO, ILLINOIS--Paleoanthropologists working in Africa have discovered stone blades more than a half-million years old. That pushes the date of the earliest known blades back a remarkable 150,000 years and raises a question: What human ancestor made them?
Not long ago, researchers thought that blades were so hard to make that they had to be the handiwork of modern humans, who had evolved the mental wherewithal to systematically strike a cobble in the right way to produce blades and not just crude stone flakes. First, they were thought to be a hallmark of the late Stone Age, which began 40,000 years ago. Later, blades were thought to have emerged in the Middle Stone Age, which began about 200,000 years ago when modern humans arose in Africa and invented a new industry of more sophisticated stone tools. But this view has been challenged in recent years as researchers discovered blades that dated to 380,000 years in the Middle East and to almost 300,000 years ago in Europe, where Neandertals may have made them (ScienceNOW, 1 December 2008).
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