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By Root 677 0

in western Turkana began in 1989, led by Meave Leakey, the head of palaeontology at Kenya’s National Museums, who had taken charge of fieldwork after Richard Leakey was appointed to manage Kenya’s wildlife parks. The first site she chose to explore was Lothagam Hill, a vast slab of rock heaved upwards at an angle, exposing sediments that were between 8 and 4 million years old. Once, Lothagam had stood out as an island in a much larger Lake Turkana. A combination of volcanic activity, sedimentation and time had transformed it into a palaeontologist’s delight. Over the course of five years, Leakey’s team collected thousands of fossil specimens: extinct hippos, horses, rhinoceroses, monkeys, giraffes, birds and a huge array of fossil fish—crabs, turtles, crocodilians and rare cichlids. The diversity of animal life was remarkable. Compared to the arid landscape of modern times, the ancient rivers and lakes of the area had teemed with life. There were, however, few signs of human remains—just six hominid teeth were found during five years of searching.

In 1994, Leakey moved her team to Kanapoi, an ancient valley south of Lothagam. During the 1960s, a Harvard professor, Bryan Patterson, had made significant discoveries there. In 1965, he spotted a hominid elbow bone that was subsequently dated as about 4 million years old; it was the oldest known fossil at the time, predating anything that Louis and Mary Leakey had found at Olduvai. In 1967, Patterson uncovered part of an australopithecine jaw at Lothagam that was thought to be at least as old as the Kanapoi specimen. But both fossils were too fragmented to provide much conclusive evidence about early hominids.

Two weeks after setting up camp at Kanapoi, a member of the Hominid Gang, Wambua Mangao, found an upper jaw with three teeth. In further excavations, other fossils were uncovered, including parts of a shinbone that indicated upright walking. Announcing their finds in 1995, Leakey concluded that her team had discovered a new type of australopithecine, about 4 million years old, older than any previously known species. She named the new species Australopithecus anamensis after the Turkana word anam, meaning ‘lake’. The size of a chimpanzee, it possessed a mixture of features combining humanlike limbs with relatively apelike jaws and teeth, more primitive than Lucy’s. Leakey believed that it was the first of the australopithecines, intermediate in morphology and age between the 4.4-million-year-old Ardipithecus ramidus and the more advanced 3.2-million-year-old Lucy. As well as walking upright, anamensis retained a tree-climbing ability. The team’s anatomist, Alan Walker, pointed out: ‘These finds demonstrated that all parts of the human body did not evolve simultaneously but rather in bits and pieces, much like a mosaic’.

Another breakthrough occurred in 1999. Exploring sediments along the Lomekwi River, a member of the Hominid Gang, Justus Erus, found fragments of a skull that turned out to belong to a 3.5-million-year-old hominid that no one had previously encountered. It took Leakey’s team a whole year to reassemble the skull from bits and pieces. Even though the skull was distorted and badly abraded, Leakey was convinced that its features set it apart from its only known contemporary, Australopithecus afarensis—Lucy’s species. What was most striking about it was the forward position of its large, flat cheekbones relative to the jaws. Whereas Lucy’s protruding face resembled that of a chimpanzee, the flat face of Leakey’s specimen seemed to foretell the look of later hominids. Leakey decided therefore to assign the discovery not just to a new species but to a new genus—Kenyanthropus platyops—‘flat-faced man of Kenya’. Quite where Kenyanthropus platyops fitted into the rest of the human family tree was uncertain. Meave Leakey claimed that it shared features with Richard Leakey’s 1470 skull, otherwise known as Homo habilis but more recently named Homo rudolfensis, perhaps a direct ancestor. Critics, such as Tim White, argued that it was simply a variant of afarensis.