Team finds immediate predecessor of modern humans

Contact: James E. Rickman, jamesr@lanl.gov, (505) 665-9203 (03-078)

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LOS ALAMOS, N.M., June 12, 2003 -- An international team of scientists, including a researcher from Los Alamos National Laboratory, has discovered fossilized skulls that lend further credence to the hypothesis that modern humankind originated in Africa.

The discovery, today highlighted in two companion papers as the cover story of the journal Nature, also indicates that this ancient predecessor of modern man conducted early mortuary practices on their deceased contemporaries and may have dined on hippopotami.

The international team, know as the Middle Awash Research Group, discovered fossilized skulls of two adults and a child who lived 160,000 years ago in what is now the Afar Region of northeastern Ethiopia. The age of the fossils makes them the world’s oldest near-modern humans, meaning that they are a subspecies of Homo sapiens — modern man. Researchers named the new subspecies Homo sapiens idaltu (idaltu means "elder" in the Afar language).

The team found skull, tooth and bone fragments as well as an entire cranium in sediments near Herto village in 1997. It took researchers years to successfully reconstruct and stabilize the fossilized remains.

One of the adult skulls and the child’s skull bear marks indicating that they had been altered by stone tools. The child’s skull shows evidence of polishing, perhaps from repeated handling, in an area where the base of the cranium was broken away. Anthropologists have found similar bone modifications in societies where the skulls of ancestors were preserved and venerated, leading the research team to believe that the marks are the result of a similar mortuary practice conducted by Homo sapiens idaltu.

Los Alamos geologist Giday WoldeGabriel, a co-leader of the research team, used geologic clues to characterize and describe the environment in which Homo sapiens idaltu lived. Although much of Europe was under ice as a result of major glaciation, the ancient hominids lived near the shore of a shallow freshwater lake that had been formed by major fault that blocked a river in the area. Fossils indicate that the lake was inhabited by abundant catfish, crocodiles and hippos.

In fact, it was a fossil of a butchered hippopotamus skull discovered by professor Tim White, one of the team’s leaders from the University of California at Berkeley, that attracted the team to the excavation area where the skulls were found. Stone tool marks on fossilized remains indicate that Homo sapiens idaltu at Herto had a taste for hippo, but researchers are unclear whether the hominids hunted the animals for food or scavenged them.

The Herto fossils have lent credence to the idea that modern man originated in Africa and spread throughout the world from there. The new subspecies is anatomically similar to modern humans. Previous to the Herto discovery, the oldest near-modern humans ranged from 90,000 to 130,000 years old and were found in Africa and the Middle East. The Herto remains predate the Middle Eastern remains by some 30,000 years.

But most significant to the research team, Homo sapiens idaltu is unmistakably a non-Neanderthal. As such, the Herto fossils indicate that near humans had evolved in Africa long before European Neanderthals disappeared. Consequently, the Herto remains conclusively demonstrate that there never was a Neanderthal stage in human evolution, and that Neanderthals were merely a branch of the evolutionary tree that later went extinct, according to professor F. Clark Howell of U.C. Berkeley, a co-author of the Nature paper. The bones therefore lend further support to the "Out of Africa" hypothesis.

The Middle Awash Research Group has discovered a wealth of fossils in the Afar Region throughout the past decade. The group’s finds include fossils of six early hominids of various ages from six million- to one million years ago to the Herto fossils — the team’s youngest find to date.

Funding for the Middle Awash Research Group’s activities is supported by grants from the National Science Foundation and the University of California’s Institute of Geophysics and Planetary Physics at Los Alamos National Laboratory.

Los Alamos National Laboratory is operated by the University of California for the National Nuclear Security Administration (NNSA) of the U.S. Department of Energy and works in partnership with NNSA's Sandia and Lawrence Livermore national laboratories to support NNSA in its mission.
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