Part of the Oldowan toolkit found at Nyayanga.Photo: T.W. Plummer, J.S. Oliver, and E. M. Finestone, Homa Peninsula Paleoanthropology Project

 Part of the Oldowan toolkit found at Nyayanga.Photo: T.W. Plummer, J.S. Oliver, and E. M. Finestone, Homa Peninsula Paleoanthropology Project

The finds are among the oldest-known instances of the Oldowan toolkit, though earlier, more rudimentary tools were found in Kenya in 2011 and 2012; those tools date to 3.3 million years ago. But the upper age limit for the newly discovered tools are nearly as old, and they indicate that hominins besides early Homo may have put rock and rock together to make, erm, better rock.

“The assumption among researchers has long been that only the genus Homo, to which humans belong, was capable of making stone tools,” said Rick Potts, a paleoanthropologist at the Smithsonian’s National Museum of Natural History, in a Smithsonian release. “But finding Paranthropus alongside these stone tools opens up a fascinating whodunnit.”

Paranthropus is an extinct human relative with a broad face and a masticatory set (that is, teeth) built for chewing. Paranthropus had the largest teeth of any primate; though the hominin was smaller than a gorilla, it had larger teeth, Plummer said. Two Paranthropus molars found at Nyayanga are the extent of hominin remains on the site; one of the molars is the largest hominin tooth ever found.