"Fossils could fill gaps in human evolution. Remains from Ethiopia date back 4.5 million years" (2005)

LONDON - African fossils of one of our earliest ancestors, who lived about 4.5 million years ago, could help fill some of the gaps in early human evolution, researchers said Wednesday.

The remains of Ardipithecus ramidus could provide insights into the creatures that lived shortly after the split from the line that gave rise to chimpanzees, 6 million to 8 million years ago.

“It is a very important finding because it does confirm hominids walked upright on two feet definitely 4.5 million years ago,” paleoanthropologist Sileshi Semaw, of the CRAFT Stone Age Institute at Indiana University in the United States, said in an interview.

Only a handful of such fossils have been found since anthropologists at the University of California at Berkeley named A. ramidus nearly a decade ago.

At least nine hominids
> Semaw and his colleagues unearthed remains from at least nine primitive hominids. The teeth, jaw, and part of a toe and finger bones were found at Gona in the Afar region in northern Ethiopia, about 300 miles (500 kilometers) northeast of Addis Ababa, according to the research reported in the science journal Nature.<font>

It is one of only a few sites in Africa where hominid fossils older than 4.3 million years old have been found.

“If you go back in time, around 4.5 million years ago and older, there are only very few sites across Africa where a few jaw, finger and toe bones have been found,” Semaw said.

Ardipithecus is believed to be the earliest hominid genus after the chimpanzee split. Hominid fossils dated around 5.5 million years ago have recently been discovered and were assigned to a new species named Ardipithecus kadabba. A. ramidus is slightly younger.

“We now have more than 30 fossils from at least nine individuals dated between 4.3 and 4.5 million years old,” said Semaw.

Record of major changes
> <b>The fossils provide a record of the evolution of major anatomical and behavioral changes that define human beings, according to the researchers.

Although the remains indicate A. ramidus walked upright, it looked more like a chimpanzee than a human.

Other fossils found at the site indicate the early hominids lived in close proximity to animals such as antelopes, rhinos, monkeys and giraffes in woodlands.

“A few windows are now opening in Africa to glance into the fossil evidence on the earliest hominids, though the picture we have of their anatomy and behavior is still a blur,” said Semaw. “More hominid discoveries are needed from sites such as Gona to fully understand the biological origins of our ancestors.”

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