A mysterious but well-preserved hominid skull found nearly a century ago comes from a population that lived in Africa around 300,000 years ago, as the earliest Homo sapiens were evolving, a new study finds.
This discovery indicates that a separate Homo population, perhaps a species some researchers call H. heidelbergensis, inhabited Africa at the same time as both H. sapiens and a recently discovered population dubbed H. naledi, say geochronologist Rainer Grün and his colleagues. African H. heidelbergensis could have been a recently reported “ghost population” that interbred with ancient H. sapiens and passed a small amount of DNA to present-day West Africans, the researchers suggest April 1 in Nature.
Grün, of Griffith University in Nathan, Australia, and his team dated small samples of bone and teeth from the Broken Hill skull using measures of the radioactive decay of uranium and the accumulation of natural radioactivity from sediment and cosmic rays. Based on these techniques, the team estimates the skull’s age at between 324,000 and 276,000 years old.
Double-edged stone implements typically found at ancient H. sapiens sites were also recovered near the Broken Hill skull, suggesting that H. heidelbergensis made the same type of tools, the scientists say.