Redating specimens of Australopithecus may rewrite human history

fossil vault at the University of the Witwatersrand (Wits), in Johannesburg, contains treasure more precious than the gold that paid for the university’s establishment. It is the resting place of five of the ten known partial skeletons of early hominins, the ancestors of human beings. In a glass case at the vault’s centre, resting on blue velvet, is Little Foot, the near-complete remains of a member of the species .Wits is not the only repository of such treasures. Farther north, in Pretoria, the Ditsong National Museum of Natural History hosts the skull of Mrs Ples, a representative of , cousin to , and one of the most famous hominin yet found. That these specimens are millions of years old is not in doubt. But just how many millions is disputed. A sophisticated dating technique, called cosmogenic nuclide dating, has upended previous estimates—and, with that, is rewriting an important chapter in the story of human .