Article

KENYAN FOSSIL FINDS THROW NEW LIGHT ON HUMAN EVOLUTION

 NAIROBI, KENYA, 

Dr Meave Leakey and colleagues at the National Museums of Kenya have 
unearthed fossils belonging to a new genus of human ancestor, Kenyanthropus platyops, with profound implications for our understanding of early human ancestry. 

 The new finds, described in the March 22nd issue of the prominent  scientific journal Nature, are between 3.5 and 3.2 million years old and were recovered in 1998 and 1999 during field work sponsored by the National Geographic Society. 

Since the early 1980s, many scientists have believed that there was a single common human ancestor, which gave rise to successive species within the past 3 million years. This ancestral species, Australopithecus afarensis, is best known from the partial skeleton discovered in Ethiopia in 1974 and popularly known as "Lucy". However, the newly discovered Kenyan fossils, which include jaws and teeth in addition to a skull, are from the same time interval as Australopithecus afarensis, but are remarkably different. For example, the new Kenyanthropus skull has a much flatter face than Australopithecus. Hence, Meave Leakey says "Kenyanthropus 
shows persuasively that at least two lineages existed as far back as 3.5 
million years; the early stages of human evolution are more complex than we previously thought”. 

Of particular scientific interest amongst the new finds is the reasonably complete skull which was discovered by research assistant Justus Erus who was working with Meave and Louise Leakey near the  Lomekwi River, in northern Kenya. In addition to a flat face, the skull of Kenyanthropus has particularly small molar teeth. Both tooth size and face shape relate to the way a species chews its food. Therefore, the differences  between Kenyanthropus and Australopithecus probably show that they had different diets and could have existed side by side without direct competition for food resources. The team working on the new finds included Christopher Kiarie who carried out the painstaking laboratory preparation of the fossils, Frank Brown and Patrick Gathogo (University of Utah) who studied the earth layers in which the fossils were found, and Ian McDougall (Australian National University) who did the isotopic dating of these layers.

The analysis of the fossils has been made by palaeontologists Fred Spoor 
(University College London), and Meave and Louise Leakey. The National 
Geographic Society has sponsored Kenyan palaeontological field work by the National Museums of Kenya in the Lake Turkana basin since 1968. In addition, the geological studies for these finds were supported by the Leakey Foundation (USA) and the isotopic dating was supported by the Australian National University. 

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