Born in Africa_ The Quest for the Origins of Human Life - Martin Meredith [69]
One week later, looking through the contents of another bag, he found what proved to be a vital clue in the chain of events that followed: the slightly damaged fragment of a hominid tibia—the lower leg bone—with an oblique break just above the ankle that looked as if it could have been caused by miners’ blasting. Searching for more fragments of the same tibia, Clarke retrieved—from a bag labelled bovid (antelope) tibiae—a hominid tibia shaft with the distal end intact. This second piece of tibia turned out to fit perfectly with the other bones of the left foot of Little Foot.
Then Clarke realised that the first piece of tibia he had found came from the right leg of the same individual. He remembered finding a small foot bone in the 1994 box which, at the time, he had not been able to match with the other left foot bones. ‘When I looked at it again, I found that it was a hominid bone from the right foot, a mirror image of one of the newly discovered bones of the left foot’.
In all, Clarke had accumulated twelve foot and lower leg bones from a single individual. The conclusion he reached was crucial: ‘The fact that we now had foot and leg bones of both sides of one individual meant that the whole skeleton had to be there embedded in the breccia of that lower cave, the Silberberg Grotto’.
Clarke made a cast of the right tibia that had been broken off at an oblique angle and sent two of the Sterkfontein preparators, Nkwane Molefe and Stephen Motsumi, to look for a matching section of bone in the exposed breccia surfaces of the Silberberg Grotto. ‘The task I set them was like looking for a needle in a haystack’, recalled Clarke.
On 2 July 1997, Molefe and Motsumi began their search. The area of search included the walls, floor and ceiling. The surfaces were damp and covered in mud. The only light came from their hand-held torches. Yet on the second day they found an exact match for the cast in the side of a long slope of hard breccia. ‘The fit was perfect despite the bone having been blasted apart by lime workers sixty-five or more years previously’, said Clarke. ‘I knew then that, encased in that steep slope of ancient cave infill, we would uncover something that palaeoanthropologists had wanted for so long—a complete skeleton of Australopithecus’.
Using hand-held lamps, Clarke, Molefe and Motsumi began to chisel away carefully at the concrete-like breccia. By May 1998, they had uncovered the lower legs. But then, to their consternation, for month after month, they found nothing more. Clarke eventually deduced that the upper part of the body had collapsed into a lower cavity and had been sealed over with thick stalagmite. He selected an area of stalagmite for Motsumi to work on. The next day, Motsumi made a direct hit on pieces of bone that turned out to be the back of a lower jaw and the end of an upper arm bone. Clarke cautiously chipped away more of the rock. ‘The glint of tooth enamel sent a shiver down my spine. It was an upper molar which, together with the lower jaw, told us that we had located the skull’.
Further chiselling revealed that the australopithecine lay on its back on a slope with its left arm extended above its head, its right arm by its side and its legs crossed. The skull was complete, with only some minor cracking and displacement. The skeleton suggested it was an adult, about four feet tall, aged by palaeomagnetic dating as 3.3 million years old. Of particular significance was the discovery of a perfectly preserved hand. It was shaped like that of a modern human hand in proportion, but much more muscular, with a short palm, a long thumb and relatively short fingers. ‘Such a hand with a long and very muscular opposable thumb had apparently evolved in our ancestors for the purpose of firmly grasping branches during tree-climbing