Fossil remains first discovered five years ago were presented to the world this week
Elisabeth Lickindorf
Sensational fossil remains presented this week at Wits University have been dubbed Orpheus and Eurydice by their discoverer, Dr Andr Keyser, “because they came from the underworld”.
The remains were stumbled upon by amateur helpers volunteering on a dig and uncovered by their leader, Keyser, a retired geologist-turned-paleaoanthropologist.
Eurydice is the most complete skull yet excavated of a 1,5- to 2-million-year-old extinct female hominid cousin of our ancient ancestors. Orpheus is a large male jawbone.
Keyser’s exciting announcement this week at the Bernard Price Institute for Palaeontological Research at Wits lifts the curtain on the riches of his new fossil- bearing site at Drimolen in the Sterkfontein Valley, part of the World Heritage site declared by Unesco in December.
The genus is identified controversially by Keyser as Paranthropus – “nearly like man”, rather than Australopithecus, which signifies “southern ape of Africa” – because, he says, “it has a more humanlike than apelike shape”. It’s a controversial designation, since the terms have not been universally defined – because the number of specimens found in the world so far is so tiny, and the number of good ones tinier still. Keyser and his colleagues have agreed to differ: “It’s more a matter of taste than of science at this stage.”
Paranthropus robustus is thought to have become extinct after a little over a million years of existence; the oldest known specimen dates back to 2,5-million years and the youngest about 1,3-million.
The skull (nicknamed Eurydice, but classified as DNH7), complete with the huge teeth that typify robustus, will give scholars material for conclusions about the extent of the sexual dimorphism of the species. Differences between the male and female fossils are pronounced: her shape is more slender than the male, says Keyser. No crest protrudes in a ridge along the top of her head and, though neither has a nose that protrudes from behind the cheekbones, her face is flatter and less dish-shaped.
Forensic experts say that a female skull has bigger and rounder eye sockets than males, he adds tentatively, though anthropologists have not accepted this as an ancient hominid characteristic.
About five or 10 centimetres from the skull was a Paranthropus robustus male jawbone with all its teeth (Orpheus, classified as DNH8). “This must be male,” Keyser says, “because the teeth are much bigger than those of the skull and the mandible’s more massive. But we can tell that both belong to the same species because of the distinctive big cheek teeth and tiny front teeth.”
The first sight of the skull, on October 21 1994, was a happy and unexpected accident. “We were getting help from amateurs who belonged to an outdoor recreation club,” says Keyser. “Rosalind Smith was digging away at a fossilised antelope horn in black soil – which we later realised was breccia that had decalcified – and suddenly saw what she thought was another baboon. Then we saw the teeth.
“I took over immediately, brushed the soft soil carefully from around it, and there was the outline of a beautiful skull and its mandible, perfectly preserved. Not far from the skull, we found an enormous lower jaw with huge teeth.
“We don’t expect they knew each other in real life, of course, because these fossils were washed down from deposits in an upper cave, but we like to think that maybe they might have loved each other many generations apart. Now we’ve had the privilege of bringing them to the surface at last.”
Five years on, the preliminary reconstruction is complete. In three sections – mandible, face, and braincase – the precious female skull, together with the male mandible, rest in state on a black velvet pad.
Keyser calls himself a “back to basics” rather than a “modern style” scientist. “The emphasis is now on the technology, but detailed comparison of measurements is not really my calling. I think the breakthroughs are what you find, and what you can deduce from what you find.”
He deduces that the climate and environment in which Paranthropus robustus thrived was much like today’s. “We’ve found fossil remains of extinct forms of springbok, blesbok, and other specialised grass-eaters at this site – two elephants so far, hartebeest, sabre- tooth cats and a leopard-type creature. There were also hunting hyenas with long legs and huge skulls. They must have been formidable predators.
“What I can’t understand is why there are no horses; all the other caves around are full of zebra. Perhaps the site was too rich? We know they’re adapted to short grass and desert environments.
“Thanks to owls roosting in the caves, there are also tons of mouse bones in the deposit, and sifting them out takes up a lot of our time. On the other hand, we’re happy when we find them, because, curiously enough, wherever we found them, we also found hominids. For a few years we were finding a hominid a week – which is incredibly rich.
“If people ask me what I’d like to find now,” says Keyser, “I tell them: I’ve got hominids, and now I want a pig. They underwent a remarkable evolution during the Plio-Pleistocene, so they’re marvellous for dating.”
Paranthropus robustus shared the area with forms of early Homo, confirms Keyser, and he concurs with others that the species might have gone extinct as it tried to compete for the same resources. Its huge teeth – double the size of a modern human’s – had possibly adapted to a vegetarian diet, with front teeth worn flat like pencil stubs. But tests found low levels of strontium in the bone, an indication that Paranthropus was a carnivore.
It is not impossible that DNH7 and DNH8 fashioned tools out of bone or even stone, Keyser says, though the presence of early Homo remains at the site means that either or both could have been responsible for the 24 specimens of what he thinks are bone tools.
Keyser is uniquely qualified for his pioneering work. As an experienced geologist he understands caves, how to find them and interpret their sediment. Knowing how the caves formed and filled up, and how the fossils got in, he can evaluate the size and extent of the deposit, which shows him exactly how to excavate it.
He retired in 1993 from his work as a geologist for the Geological Survey (now the Council for Geoscience). In that position he had had a blanket excavation permit. Ever since his undergraduate studies at the University of Pretoria, where he read geology and zoology, he had had a passionate interest in fossils. He had planned, after retirement, to carry on digging and do some painting – he is a watercolourist. “I didn’t want to be this busy,” he insists. “I just wanted to have a hobby.” But he found “this anthropology business” taking over his spare time, and also, for a while, his entire pension.
For the first few years “I had to fund my excavations out of my own pocket, which was hard on my wife, but she agreed to it. My permit had expired when my job ended, but thanks to Professor Phillip Tobias at Wits, I became an honorary research associate of his palaeoanthropology research unit and, with his help, got an excavation permit, so I could carry on working.”
Drimolen has become part of the Rhino and Lion Nature Reserve, and with the support of its new owner, Ed Hearn, the work continues. Even though Keyser does not earn a salary, the costs of the Drimolen excavation are now covered by the Palaeoanthropological Science Trust, the National Geographic Society, the LSB Leakey Foundation, and the Cultural Division of Foreign Affairs of the Republic of France.
Saved from industrial development because of its World Heritage site status – and because the dolomite sinkholes, mercifully, make serious building too dangerous – Drimolen potentially has a colossal palaeoanthropological future. But, observe Keyser and others, virtually no young South African academics are moving into this field of research because they need to make a living, and neither positions nor funding are available for them here.
Keyser warns that South Africa may find itself reduced to the status of a laboratory for foreign scientists. “I couldn’t get a job today as a specialist reptile palaeontologist, for instance,” says Keyser.
“We need to move away from the idea that science has to pay for itself and to remind ourselves that there is such a thing as a national intellect. We must preserve our history and our culture, and fund it as our national responsibility.”
Scientific details of the Paranthropus robustus fossils appear in the April edition of the South African Journal of Science