A 1.84-million-year-old finger bone from Tanzania is the oldest known hominin hand bone with human-like features.

Ancient human relatives used stone tools 2 million to 3 million years ago, but had hands that were suited to living in trees. A team led by Manuel Domínguez-Rodrigo at Madrid's Institute of Evolution in Africa found a finger bone at a site in Olduvai Gorge, Tanzania, in 2013. The bone, named OH 86, is longer and straighter than those of earlier australopiths and similarly aged Homo habilis hand bones found nearby. Its closest match in size and shape in the fossil record is a finger bone from early Homo sapiens.

The finding suggests that some human-like traits emerged early in human evolution, and that a modern-looking hominin lived alongside more primitive-bodied creatures in East Africa some 2 million years ago.

Nature Commun. 6, 7987 (2015)