The Japan Times, April 6, 1999
By VILEM BISCHOF
First upright apes may have walked in 15 million B.C.
PARIS (AFP-Jiji) A primitive ape walked upright as long as 15 million years ago, French paleontologist Yvette Deloison estimates.
Deloison, with France's National Center for Scientific Research, said last week that certain species of apes later abandoned the bid to stand upright, while our ancestors became permanently bipedal.
The theory is considered groundbreaking, and could disprove the theory that "Lucy," a 3.2 million year-old Australopithecus discovered in 1974 in Ethiopia, is one of humanity's oldest ancestors.
"Lucy," said Deloison, "has bipedal characteristics, ... but she also has divergent big toes like those used by the big primates of today to climb trees."
"Evolution never goes backward," she said. "The human foot, highly specialized for bipedal use, cannot have been derived from a foot adapted to climbing trees, which is also highly specialized but different.
"Lucy thus cannot be the ancestor of humanity and, in consequence, to find the origins of biped creatures one has to look to much older four-footed primates that finally stood upright."
Deloison said she believed there were three species of two-footed primates. The first developed into hominids, the second became Australopithecines and the third developed into orangutans, gorillas and chimpanzees.
Her theory is backed by recent discoveries.
Australopithecus anamensis, discovered in 1995 in Kenya, was bipedal 4 million years ago. And in December, scientists in South Africa discovered an Australopithecus skeleton at the fossil-rich Sterkfontein caves.
Ron Clarke, who headed the excavations, said, "The anatomy of the ankle joint shows (it) was already bipedal but able to climb in trees by virtue of a divergent big toe."
Deloison said the front of the foot of the South African Australopithecus was designed for tree-climbing, while the back and the top were more bipedal.
"This fossil is about the same age as Lucy, or a little older, around 3.3 million years old. So now we have a 4-million-year-old Australopithecus that was perfectly two-footed, and two more recent skeletons that are less bipedal," she said.