scientists working in the desert badlands of northwestern kenya have found stone tools dating back 3.3 million years, long before the
1 of modern humans, and by far the oldest such artifacts yet discovered. the tools, whose
2 may or may not have been some sort of human ancestor, push the known date of such tools back by 700,000 years; they also may challenge the notion that our own most direct ancestors were the first to bang two rocks together to create a new technology. the discovery is the first evidence that an even earlier group of proto-humans may have had the thinking abilities needed to figure out how to make sharp-edged tools. the stone tools mark "a new beginning to the known archaeological record," say the authors of a new paper about the discovery, published today in the leading scientific journal nature.
"the whole site's surprising, it just rewrites the book on a lot of things that we thought were true," said
3 chris lepre of the lamont-doherty earth
4 and rutgers university, a co-author of the paper who
5 dated the artifacts.
the tools "shed light on an unexpected and
6 unknown period of hominin behavior and can tell us a lot about
7 development in our ancestors that we can't understand from fossils alone," said lead author sonia harmand, of the turkana basin institute at
8 9 university and the universite? paris ouest nanterre.
hominins are a group of species that includes modern humans, homo sapiens, and our closest
10 ancestors. anthropologists long thought that our relatives in the genus homo - the line leading directly to homo sapiens - were the first to craft such stone tools. but researchers have been uncovering
11 clues that some other, earlier species of hominin, distant cousins, if you will, might have figured it out.
the researchers do not know who made these oldest of tools. but earlier finds suggest a possible answer: the
12 of a 3.3-million-year-old hominin, kenyanthropus platytops, was found in 1999 about a kilometer from the tool site. a k. platyops tooth and a bone from a skull were discovered a few hundred meters away, and an as-yet unidentified tooth has been found about 100 meters away.
the precise family tree of modern humans is
13, and so far, no one knows exactly how k. platyops relates to other hominin species. kenyanthropus predates the earliest known homo species by a half a million years. this species could have made the tools; or, the toolmaker could have been some other species from the same era, such as australopithecus afarensis, or an as-yet undiscovered early type of homo.
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