Discovery of the Most Complete Australopithecine Skeleton Yet Found, from Sterkfontein, South Africa
Photo by Robert Jurmain with the kind permission of Dr. R.J. Clarke Finding hominid fossils is always a fortuitous undertaking. Most commonly (and still requiring considerable luck), one or two pieces of an individual are found. Only when extraordinary preservation conditions allow, are more complete individuals recovered. For example, there is the famous “Lucy” find, comprising 40% of a skeleton, from the Hadar site in Ethiopia. Dating back to discoveries in the 1940s, from South Africa as well, a few partial skeletons have been found at the Sterkfontein site. Indeed, Sterkfontein has in recent years yielded a large number of new hominid fossils – making it the richest single early hominid site (with finds now totaling more than 700 specimens). Certainly, the most dramatic new discovery (and among the most significant of all early hominid discoveries) is the australopithecine skeleton found in 1997. This discovery was not entirely luck, of course, and the circumstances surrounding it read like a detective story. New explorations in the western extension of Sterkfontein cave in 1992 uncovered several hominid foot bones of the same individual. Provisional dating has indicated these may be the earliest hominid fossils from South Africa, with an estimated age of 3.3 m.y.a. These foot bones show an unusual combination of hominid and ape-like features, as reported by Ron Clarke, the director of excavations at Sterkfontein and renowned South African paleoanthropologist, Phillip Tobias. Popularly labeled by Tobias as “little foot,” this fossil became somewhat of a celebrity in South Africa (it is more technically referred to as Stw-573). After its initial publication (in 1995), Clarke continued to look for other pieces and found several more foot and lower leg elements (some of which had been mislabeled and placed in a bag with monkey fossils!). Dr. Clark realized that so many preserved elements might suggest yet more of this fossilized individual might still be embedded within the cave. But where? These fossils were originally blasted out with dynamite and thus could have come from anywhere within a vast subterranean, dark, and complex cavern. Not to be deterred, Clarke sent two of his assistants (Stephen Motsumi and Nkwane Molfe) to search the cave to see if they could locate any more of the skeleton.
Amazingly, after just two days of searching, Mrs. Motsu and Molfe found a piece of a lower leg eroding out ofthe limestone – and it fit exactly with one of the bones blasted out years before! Now began the extraordinarily delicate task of removing the cemented limestone matrix surrounding the fossils. Only in this way could the remainder of the skeleton be unearthed without damaging it. Lying on his side on a steep slope, lit only by hand-held lamps, Ron Clarke has spent much of the last five years millimeter by millimeter slowing drilling and chipping the sediment. Before Clarke’s eyes has appeared the most complete australopithecine individual ever recovered, lying as he or she died, with many of the bones still in their proper anatomical articulation. Nothing like this has ever been found. To date, portions of both legs, a complete cranium, (with lower jaw articulated), and part of an arm have been unveiled (the latter with a mostly complete hand, again still articulated; see photo). Dr. Clarke hypothesizes this individual probably fell, accidentally slipping through an opening in the cave roof. This unfortunate australopithecine may have died form the trauma of the fall or perhaps perished a few days later, trapped without food inside the cave. The bones remained in place, as erosion was minimal. Since the fossilized bones show no sign of animal gnawing, it appears that scavenging (so typical at most sites) was also absent. This combination of circumstances is what has led to such remarkable preservation. But there may have been yet further unusual features at work. Archaeologists who excavate much more recent burials, including those only a few centuries old, hardly ever found bones still articulated (especially small elements, such as those in the hand). Only when some kind of mummification has occurred, preserving soft tissues, will these bones stay in position. Accordingly Ron Clarke has surmised that Stw-573 may have been mummified, perhaps for centuries, before the remains became fossilized. References Clarke, R.J.
and P.V. Tobias Clarke, R.J.
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