`MISSING LINK' BONES TURN UP IN S. AFRICA.

Byline: John Noble Wilford The New York Times

In a discovery that may answer some of the ``missing link'' questions of human evolution, scientists in South Africa have found what they described as the best-preserved and most nearly complete skull and skeleton yet seen of any very early member of the human family tree.

The head-to-toe fossil remains of a 4-foot-tall being who lived sometime between 3.2 million and 3.6 million years ago were uncovered in the depths of a limestone cave near Johannesburg, the discoverers said Wednesday. The specimen is older and much more complete than the famous ``Lucy'' skeleton found in Ethiopia in 1974.

Paleontologists will not be able to identify the species of this hominid, or human forerunner, until all the bones are removed from the rock layers where they are embedded in the Sterkfontein cave, the site of many discoveries of early-human remains. But the scientists already know enough, they said, to be excited about what the fossils may tell them concerning the anatomy and evolution of early human ancestors.

``It's one of many missing links from ape to man,'' Ronald Clarke, a paleontologist at the University of Witwatersrand in Johnannesburg, said at a news conference there. A brief announcement about the skeleton is appearing in today's issue of the journal Nature. A detailed description of the find was published in the South African Journal of Science.

Clarke made the original discovery, of foot bones from the skeleton, in 1994 and came upon more pieces in a university storeroom. Then he led excavations at the cave that uncovered the long limbs, the torso and the almost complete skull, including both jaws with full sets of teeth in place.

In a telephone interview, his mentor, Phillip Tobias, also a Witwatersrand paleontologist, said: ``It really is a magnificent specimen. It's the first time we have a virtually complete skeleton of an australopithecine, or ape-man. It's the most important find in paleontology in Africa since the Taung child.''

The discovery of the Taung child's skull in South Africa in 1925 led to the classification of small-brain protohumans in the genus Australopithecus and set in motion this century's explorations of human origins in Africa. Several other paleontologists, though impressed by the new find, were not yet ready to agree on so lofty an assessment of its significance.

Perhaps of greatest potential importance, paleontologists said, is that the new Sterkfontein skeleton should yield insights into a time of transition in hominid locomotion.

Ample evidence has shown that australopithecines were walking upright by this time, but the first traces of this skeleton - the four bones of an instep and beginning of the big toe - suggested that this species also was capable of grasping and climbing like a chimpanzee. These upright walkers on the ground might have fled back into the trees for safety or foraging.

``This is the same chap we called `little foot' in 1995,'' Tobias said, and Clarke added, ``It's important that for the first time, we will be able to relate locomotion inferred from limb bones with a skull.''

Scientists have found evidence of upright walking, or bipedality, in hominid fossils as much as 4 million years old, which is about 1 million to 3 million years after the hominid line split from the ancestors of the chimpanzees and gorillas.

Once the newly discovered bones are removed for closer examination, one of the first things paleontologists will study are the hip and leg structures to see if they bear out the tree-climbing theory, advanced by Jack Stern and Randall Susman, anatomists at the State University of New York at Stony Brook.

In an interview, Susman said the skeleton discovery was ``very, very fascinating and extremely important'' because it seemed to ``hammer home the idea that these early hominids had small body sizes and were climbing trees if they got in a jam and wanted to escape.''

But Susman, who recently returned from a visit to the Witwatersrand paleontologists, said he suspected that Clarke, in an earlier interpretation, had overemphasized the Sterkfontein individual's strong chimplike anatomy and behavior.

Susman said he doubted that the specimen would turn out to be much more primitive than Lucy, a representative of the Australopithecus afarensis species that seems to have spanned a period of almost a million years, up until about 3 million years ago.

F. Clark Howell, a paleontologist at the University of California at Berkeley, lauded Clarke for his determination in tracking down almost all the skeleton. ``The fact that the whole skeleton seems to be there is little short of incredible,'' he said.

From what the discoverers could determine, the individual - whether it is male or female has not been determined - probably was walking or running when it fell into a 45-foot shaft leading to the floor of the cave. The victim either died in the fall or was injured and unable to get out of the cave, eventually dying there of starvation and exhaustion.

By studying the anatomy, working out details of stature, estimated body mass and other characteristics, Howell said, scientists should be able to gain ``a much better appreciation of the life history and behavior of an early hominid, compared to chimps.''

In the South African journal article, Clarke wrote, ``I prefer to reserve judgment on the fossil's exact taxonomic affinities, although it does appear to be a form of Australopithecus.''

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PHOTO This skull, part of what is believed to be the first complete skeleton of a human ancestor dating back more than 3 million years, was found in a cave near Johannesburg, South Africa.

University of Witwatersrand