Found in a hilltop cave, the oldest known Homo erectus and Paranthropus robustus fossils shed light on a critical period of hominin evolution.
n the winter of 2015, Jesse Martin and Angeline Leece were extracting what they thought were baboon remains from a piece of rock. The two students at La Trobe University in Australia were part of an expedition to collect and study fossils from the Drimolen quarry northwest of Johannesburg, South Africa. As they cleaned the skull fragments and pieced them back together, however, they realized the fossils did not come from a baboon, but instead comprised the braincase of a young Homo erectus, a species never before identified in South Africa.
“I don’t think our supervisors believed us until they came over to have a look,” Martin recalls.
The braincase was described in the journal Science today, together with the skullcap of another ancient hominin, Paranthropus robustus, found at the same site. A suite of different dating techniques all hinted that the two species’ braincases were more or less the same age—about two million years old. This would make them the earliest fossils ever found for their respective species, according to the new study coauthored by Martin and Leece.
“I think they have made a strong case for the oldest Homo erectus in Africa, and in fact, in the world,” Lee Berger, a paleoanthropologist at the University of Witwatersrand, says in an email. A National Geographic Society explorer-at-large, Berger was not involved in the new study.