the human record is written not only in alphabets and books, but is
preserved in other kinds of material remains in cave paintings, pictographs, discarded
In recent years, paleoanthropologists have found perhaps as many as five species that
are older than A. afarensis—in some cases much older.
Just last year, Michel Brunet of the University of Poitiers, in France, and his team of
explorers announced that amid the sand dunes of the Sahara they had found a species
between 6 million and 7 million years old:
Sahelanthropus chadensis.
These new fossils have thrown cherished orthodoxies into question.
"We saw human evolution as a nice, straight line," says Leslie Aiello of University College
London. Now some researchers are arguing that human evolution looked more like a
bush, with lots of species branching off in different directions.
No new orthodoxy has gained enough strength yet to take over the old one. Instead,
there's lots of debate.
Some paleoanthropologists, for example, have declared Sahelanthropus to be on the
line that led to gorillas, not humans.
"That's crazy," replies Brunet, who points to small teeth and other key traits that link the
creature with hominids rather than apes.
But while Brunet is confident he has discovered the oldest known hominid, he doesn't
think it's possible yet to make grand pronouncements about the shape of the hominid
tree and its various branches.
"You can't say that it's bushy," he says. "Maybe it is; we don't know. Our story has just
doubled in time, and we're just beginning to understand it."
