Born in Africa_ The Quest for the Origins of Human Life - Martin Meredith [73]
A variety of other australopithecines then appear on the scene, including several species from southern Africa. Cave sites in Sterkfontein Valley, to the west of Johannesburg, have produced a plethora of specimens. Among the oldest is Little Foot, the Sterkfontein australopithecine found by Ron Clarke, dating back 3.3 million years, regarded as a possible antecedent to Australopithecus africanus. Africanus itself prospered for a period of a million years, from 3 to 2 million years ago. First named by Raymond Dart upon discovering the Taung child which lived about 2.7 million years ago, africanus shares more features with the later Homo species than any previous australopithecine. Although its brain size was similar to that of apes—about 400 cubic centimetres—its braincase was shaped like that of a Homo. It also had a relatively flat face and short jaw.
Another branch of the australopithecines—the ‘robust’ variety—crops up at sites in both southern and eastern Africa. The first evidence of their existence was discovered in 1938 by Robert Broom, who coined the name ‘Paranthropus robustus’ to account for their massive chewing teeth. A later generation of palaeontologists took up the name when sorting out classification. Louis Leakey’s Zinjanthropus became known as Paranthropus boisei, along with other Paranthropus discoveries in eastern Africa. The size of their jaws and teeth is attributed to changes in diet brought on by the effects of a drier, cooler climate. They became specialised plant-eaters, adapted to eating hard nuts and seeds and large quantities of coarse, fibrous roughage low in nutritional value. Although their brain size increased to about 500 cubic centimetres, their fate was to head into an evolutionary cul-de-sac. In eastern Africa, Paranthropus boisei survived for nearly 1 million years, from 2.3 to 1.4 million years ago, before becoming extinct. In southern Africa, Paranthropus robustus is estimated to have lived between 2 and 1.5 million years ago.
As a group, the australopithecines were remarkably successful. They persevered on earth for a period of 3 million years, exploring and adapting to new habitats, developing their bipedal gait and use of hands, and expanding the range of their food sources. It was from their ranks that the first species of Homo emerged. Despite their small brains, they may also have been responsible for producing the first primitive stone tools—the world’s first technology.
The oldest recognised stone tools—consisting of sharp flakes chipped off small cobbles and hand-sized stone hammers used to hit the cores—date back to 2.6 million years ago. They come from a site on the Gona River in Ethiopia’s Awash Valley, five miles to the west of Hadar, where Lucy was found in 1974. What is notable about them is the degree of skill involved in their making. The toolmakers were selective about what types of stone they chose, collecting particular kinds of cobbles they knew would flake more easily, sometimes from distant locations. Cut marks found on animal bones at the site indicate that sharp-edged flakes were used for cutting meat from carcasses and for cracking open bones for edible marrow.
Further evidence of skilful tool-making comes from Lokalalei, a site to the west of Lake Turkana in Kenya dating back to 2.3 million years ago. Researchers there have found what they termed ‘a tool factory’ where toolmakers turned out hundreds of flakes, striking cobbles at the right angle and with the right force to give them effective results. The toolmakers appeared to prefer phonolite as their raw material, producing as many as thirty flakes from a single core; other types of rock were found with only a few fragments missing, suggesting they had been tested and then discarded.