Not the oldest hominid

At 4.4 million years old, Ardipithecus ramidus is not the oldest known hominid. In 2002, scientists announced they had discovered a hominid skull from the Sahel region of Chad. Named Sahelanthropus tchadensis, the species dates to about 7 million years ago. And a few years earlier, scientists had announced the discovery of several hominid fossils, including a thigh bone, in Kenya that dated to about 6 million years ago. They named the species Orrorin tugenensis.

Now that Ardipithecus ramidus has been fully analyzed, its discoverers say all of these early hominid species probably represent just one genus. Yet it’s still not clear if Ardipithecus represents a side branch in the human family tree or possibly a direct ancestor to the later australopithecines like Lucy.

Erin Wayman
Thursday, October 1, 2009 - 15:00