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PALAEOANTHROPOLOGY Oldest stone tools raise questions about their creators The 3.3-million-year-old implements predate the first members of the genus.

BY EWEN CALLAWAY, SAN FRANCISCO that complex toolmaking began with Homo. Harmand suggests that earlier species, such as

he oldest stone tools on record may platyops, bones of which have MPK/WTAP spell the end for the theory that com- been found on the western shore of Lake Tur- plex toolmaking began with the kana, and A. afarensis, may have made tools Tgenus Homo, to which humans belong. The by building on the cruder abilities seen in apes 3.3-million-year-old artefacts, revealed at a and monkeys. The Lomekwi tools were made conference in California last week, predate the in a forest environment, also questioning the first members of Homo, and suggest that more- idea that open landscapes catalysed tool use, ancient hominin ancestors had the intelligence said Harmand. and dexterity to craft sophisticated tools. Alemseged sees the Lomekwi tools as vin- “This is a landmark discovery pertaining to dication for his team’s controversial find of one of the key evolutionary milestones,” says cut-marked bones. Before Harmand’s presenta- Zeresenay Alemseged, a palaeoanthropologist tion, Alemseged’s colleague Jessica Thompson, at the California Academy of Sciences in San an archaeologist at Emory University in Atlanta, Francisco, who attended the talk at the annual Georgia, presented an analysis of other animal meeting of the Paleoanthropology Society in bones from Dikika. None contained similar San Francisco, on 14 April. patterns to those reported in 2010, suggesting More than 80 years ago, anthropologist that the marks were made by something other Louis Leakey found stone tools in Olduvai than wear and tear — probably by tools. Gorge in Tanzania. Decades later, he and his The Lomekwi talk left David Braun, an wife Mary and their team found bones from a archaeologist at George Washington Univer- species that the Leakeys named sity in Washington DC, itching for further — ‘the handy man’. This led to the prevailing Excavators at Lomekwi, , in 2011. details. He says that the tools look authentic, view that human stone-tool use began with as does the date that Harmand and her team Homo, a group that includes modern humans New York set out in 2011 to find tools older assert. The identity of their makers has aroused and their big-brained and tall forebears. The than 3 million years, at a site west of Kenya’s his curiosity: “What the hell do these things oldest of these tools date to 2.6 mil- . On a July day, the team took a look like if they can use 15-kilogram tools?” lion years ago — around the time of the earliest wrong turn and happened upon a patch of land But he is most interested in what the Lomekwi Homo fossils. Climate upheavals that trans- that seemed worth exploring. By tea time, they tools meant for their creators. Did they offer an formed dense forest into open savannah might had found pieces of rock lying on the ground advantage over the other hominins that were have catalysed ancient humans into developing that looked like flakes left over from the manu- around at the time, or was tool­making more the new so that they could hunt or facture of stone tools. Careful excavation of the common 3 million to 4 million years ago than scavenge grass-eating animals, the theory goes. patch revealed 19 buried artefacts, including existing evidence suggests? “They’re a game- Chimpanzees and other non-human stone core forms, and dozens more on the sur- changer,” he adds, “no matter what.” ■ primates use stones to crack nuts, for instance, face. One key surface find was a small rock flake, but their tools lack the craftsmanship of the which fitted in a gap in a buried core as snugly as Oldowan toolmakers, who would strike one a jigsaw puzzle piece, confirming that the tools CORRECTIONS rock against another, breaking off flakes to were made through a flaking process. The News story ‘Hope for science in fallout leave a sharp-edged stone core. The tools come from sediments that of nuclear deal’ (Nature 520, 274–275; In 2010, Alemseged and his team reported Harmand’s team dated to around 3.3 million 2015) wrongly stated that Iran found a an intriguing find at a site called Dikika in years ago and are much larger than the Oldowan bank willing to accept its payment of dues (S. P. McPherron et al. Nature 466, artefacts: some weigh as much as 15 kilograms. to CERN. It was CERN, not Iran, that found 857–860; 2010). They saw cut marks on bones The team concluded that the tools represent the bank. In addition, the text implied from 3.4 million years ago, when ape-like crea- a distinct culture, which they have named the that Iran is a full member of CERN — it is tures such as afarensis — the Lomekwian culture after the site where the involved in specific projects at the lab. And same species as the famous fossil called Lucy implements were found. “Lomekwi marks a the News story ‘Leading scientists favour — roamed eastern Africa. This hinted at even new beginning to the known archaeological women in tenure-track hiring test’ (Nature earlier manufacturing of stone tools. Other record,” Harmand said at the meeting. 520, 275–276; 2015) misidentified Virginia researchers questioned the find, attributing the Hominin fossils and cut-marked animal Valian as a linguist. She is a psychologist. It marks to natural wear and tear such as tram- bones have not been found at the site, so the also misrepresented her views on the study pling, or bites inflicted by crocodiles. team cannot yet say who made the tools or by Williams & Ceci: she has reservations Aware of this controversy, a team led by how they were used. But their discovery may about aspects of the study’s methodology. Sonia Harmand of Stony Brook University in deliver a fatal blow to the already fragile idea

23 APRIL 2015 | VOL 520 | NATURE | 421 © 2015 Macmillan Publishers Limited. All rights reserved