Scientists have unearthed in Ethiopia three 160,000-year-old skulls that they say are the oldest near-modern humans on record. Telltale marks on the bones suggest that the hominids engaged in mortuary rituals. The fossils are described in two reports published today in the journal Nature.

A team led by Tim White of the University of California at Berkeley, Giday WoldeGabriel of Los Alamos National Laboratory and Berhane Asfaw of the Rift Valley Research Service in Ethiopia recovered the fossils near a village known as Herto in Ethiopia's Middle Awash region. The researchers found them, together with bone fragments and teeth from seven other individuals, among hippopotamus bones and a variety of blades and other tools. The three skulls--belonging to two adults and a six- to seven-year-old child--share a number of traits in the face and braincase with modern humans. But slight differences in the morphology convinced the scientists to assign the fossils to a subspecies, Homo sapiens idaltu. Paleoanthropologist Chris Stringer of the Natural History Museum in London writes in an accompanying commentary, however, that "despite the presence of some primitive features, there seems to be enough morphological evidence to regard the Herto material as the oldest definite record of what we currently think of as modern H. sapiens."

The new finds lend support to the so-called Out of Africa hypothesis, which holds that H. sapiens arose as a new species between 150,000 and 200,000 years ago in Africa and subsequently replaced archaic humans such as the Neanderthals. "These fossils show that near-humans had evolved in Africa long before the European Neanderthals disappeared," says team member Clark Howell of Berkeley. "They thereby demonstrate conclusively that there was never a 'neanderthal' stage in human evolution." But whether early modern human morphology originated solely in East Africa or emerged in a number of populations around the continent remains unknown. Stringer notes that future fossil finds, as well as improved dating of previously discovered remains, should help further unravel the mystery.