(c) 1995 Associated Press
JOHANNESBURG, South Africa (Jul 28, 1995 - 08:42 EDT) -- Four small foot
bones found among discarded fossils last year bolster the belief that
humanity's evolution from apes included a phase as a walking, climbing
creature, two South African scientists said Friday.
The discovery by Ronald Clarke and Phillip Tobias of the University of the
Witwatersrand in Johannesburg adds new evidence to a longstanding debate
over how the human race developed.
Tobias and Clarke, at a news conference complete with fossil bones and
plaster casts of human and ape feet, said their find proved an ape-man
known as Australopithecus had human and apelike features.
In particular, they said the foot bones discovered by Clarke last year in
bags of discarded fossils from the Sterkfontein caves northwest of
Johannesburg showed the ape-man -- from an estimated 3.5 million years ago
-- could walk upright but had an apelike big toe capable of grasping and
more movement than a human big toe.
"The ankle bone was perfectly human," Tobias said. "But as we traveled
toward the big toe, more and more chimpanzee features appeared."
An article on the find by Tobias and Clarke appeared in today's edition of
Science, the weekly journal of the American Association for the
Advancement of Science in Washington, D.C.
Two major bodies of thought comprise the debate over human development.
One, supported by Tobias and Clarke, says ape-men gradually evolved from
four-legged tree dwellers to two-legged creatures that walked upright but
retained ape-like features to grasp tree branches with their feet.
Another, espoused by a group that includes Owen Lovejoy of Kent State
University in Kent, Ohio, says humans always walked upright and were
plains-dwellers who never lived in trees.
Lovejoy, in an accompanying article in Science magazine, said Tobias and
Clarke ignored bone structures in the hips and spine that indicated
ape-men walked upright.
Basing such a major theory on four foot bones was "mechanically and
developmentally naive," he wrote.
But Tobias said unassailable evidence now exists supporting his theory.
Other findings showed the ape-man's knee and shoulders retained features
of a climber, he noted.
"Australopithecus was far more ape-like in many of its features than we'd
ever dared imagine previously," he said.
The exact species of Australopithecus to which the four foot bones, from
the same left foot, belonged remained unclear, Tobias said. Two species,
determined by teeth and other features, have been found in South Africa,
while at least two others were discovered in east Africa in the famous
finds of Tanzania and Ethiopia.
How Clarke discovered the fossils also was a bit inexact. The stones from
which the new find came originated a deep layer estimated to be 3.5
million years old.
In the 1920s, part of the layer was blasted out and the refuse rock left
lying underground. It was eventually collected and brought to the surface,
but processing failed to turn up the four foot bones.
Last year, Clarke was perusing some bags of the discarded fossils for
evidence of animal life from the early era. He spotted a decidedly
humanlike ankle bone instead.
"I said out loud, 'Wait a minute, this isn't a carnivore, this is a
hominid,"' he recalled today. "I was astounded."
They called the find the most significant regarding human development in
decades and further proof that humankind originated in Africa. Hominid
fossils in Africa are older than those found anywhere else, and the theory
suggests early man migrated to the rest of the world from the continent.