jeudi, juillet 11, 2002
Après la découverte d'un nouveau crane, voila ce qu'on peut lire sur Nature (extrait):
Where then does Toumaï fit on the family tree? He could belong on the chimp or hominid lines, or he could be part of a different branch of the family, more distant from both chimps and humans that either is from the other.
"I'm willing to bet some money that this is a hominid," says Lieberman.
Palaeoanthropologist Tim White of the University of California, Berkeley, agrees. He thinks that Toumaï might belong to Ardipithecus, a group defined by fossils dating from about 5.5-4.5 million years ago.
But Wood takes a different view. "My guess is that it's neither a chimp nor a human ancestor - it's a creature that was living at the same time."
To solve the mystery we need more fossils from the same period. Unfortunately our relatives' habits may be against us. The forests favoured by chimps, and apparently by early hominids, are not conducive to fossil formation. Chimps, for example, have no fossil record.
On the bright side, Toumaï's discovery suggests that, even if they were rarely fossilized, ancient apes and hominids roamed right across Africa. "Finding hominids in the Sahara was a bit of a long shot," says Wood. So far, most fossil hominids have turned up in the east, with a few further south.
But desert-bound palaeontologists be warned: "There are brutal field conditions," says Lieberman.
Tout n'est pas aussi simple qu'on nous l'explique dans les médias généralistes...