National Geographic News
Fossil fragments of an early species of hominid have been unearthed with rhino, giraffe, monkey, hippo, and antelope remains in Africa. Hominids are upright-walking primates including modern humans and extict and related forms. The new fossils are helping scientists piece together the earliest chapters of human evolution.
The fossils were unearthed from the Gona Study Area at As Duma in Ethiopia's Afar region and are dated to between 4.3 and 4.5 million years ago.
The research team said the fossils were of the Ardipithecus ramidus species. This hominid species lived shortly after hominids split from the common ancestor that gave rise to both chimpanzees and hominids some six to eight million years ago.
Hominids gave rise to a number of human and near human species, including the extinct Neandertals and the hobbit-like Homo floresiensisand the only surviving species, Homo sapiens.
"Gona is only one of two sites that have produced Ardipithecus ramidus," said Sileshi Semaw, the Indiana University paleoanthropologist who led the research team. "As we go back in time prior to four million years ago, we don't have that many fossils of hominids."
As a result, Semaw added, scientists are forced to piece together this early history from tiny bits and pieces.
A. ramidus fossils were first discovered about 12 years ago about 62 miles (100 kilometers) south of Gona by anthropologist Tim White and colleagues at the University of California, Berkeley.
The newly discovered fossils consist of tooth, jaw, finger, and toe fragments belonging to at least nine individuals. The shape of the toe bones indicates that the hominids walked upright on two feet, similar to humans, Semaw said.
The Gona team published their finding this week in the science journal Nature. The research was supported in part by a grant from the National Geographic Society's Committee for Research and Exploration.
Woodlands and Grasslands
Christophe Soligo studies primate evolution at the Natural History Museum in London, England. He said that the most interesting aspect to the research at Gona is the analysis of all the big mammals found in the vicinity of the hominid fossils.
By looking at the teeth structure of these animals and the evidence of ancient plants preserved in the soils, Semaw and his colleagues determined that the environment was a mosaic of woodlands and open grasslands with lakes, swamps, and springs nearby.
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