Paranthropus molars recovered from Nyayanga site. Left upper molar (top) was found on the surface at the site, and the left lower molar (bottom) was excavated. Beginning in 2015, a series of excavations at Nyayanga returned a trove of 330 artifacts, 1,776 animal bones and the two hominin molars identified as belonging to Paranthropus, the human species’ close evolutionary relative. The artifacts, Plummer said, were clearly part of the stone-age technological breakthrough that was the Oldowan toolkit. Using a combination of dating techniques, including the rate of decay of radioactive elements, reversals of Earth’s magnetic field and the presence of certain fossil animals whose timing in the fossil record is well established, the research team was able to date the items recovered from Nyayanga to between 2.58 and 3 million years old.