A new fossil discovery that is contemporaneous with Australopithecus afarensis in the middle Pliocene has caused paleoanthropologists to admit that their claims for A. afarensis as the distant human ancestor were too simplistic.
The new fossil skull, dated at 3.5 Myr by the argon 40/argon 39 method, is quite distinct from A. afarensis, and has been given a new genus and species assignment--Kenyanthropus platyops, “flat-faced human from Kenya". It was found west of Lake Turkana in northern Kenya in August 1999 by Dr. Meave Leakey’s team. The National Museums of Kenya has designated it KNM-WT 40000. The discovery was announced in the 22 March 2001 issue of Nature.
The new skull has a flat face, high cheek bones, moderate prognathism, small molars, and lacks a depression behind the browridge. It is similar in shape to KNM-ER 1470, discovered by Meave Leakey’s husband, Richard, and dated at 1.8 Myr. The new skull has a much smaller cranial capacity than 1470, but because it is badly distorted, it’s capacity is difficult to measure. However, it is said to be the size of a chimpanzee’s skull, and in the range of the skulls of A. afarensis and A. africanus.
Certainty in the evolutionary fossil record of human ancestors is now being replaced with question marks.The authors of the Nature article, Meave Leakey and six others, show a humility different from the descriptions of sensational fossil discoveries in the past. Formerly, discoveries such as this almost always involved claims of direct human ancestry. However, the existence of A. afarensis together with Mrs. Leakey’s statement that other hominids will likely be found in the middle Pliocene make all definitive claims of human ancestry almost impossible. The abundance of alleged human species in the Pleistocene could well be matched by an abundance of alleged human ancestors in the Pliocene. Certainty in the evolutionary fossil record of human ancestors is now being replaced with question marks.
Creationists will claim, correctly, I believe, that the lack of specificity in the human fossil record is further proof that human evolution is a philosophical, rather than a scientific concept. Paleoanthropologists, never troubled by a lack of specificity, will claim that linear evidence for human evolution is not necessary. The diversity of the human fossil record is now so similar to the bush-like fossil record of other animals that further evidence is unnecessary.
As long as A. afarensis was the only possible human ancestor in its time-span, it was easy for evolutionists to claim that it was in our family lineage. This in spite of the fact that there is no diagnostic tool, no methodological formula, let alone any genetic technique, to prove such a relationship. This new discovery will help force paleoanthropologists to be more straightforward in their assessments. One of the most honest statements made recently by a paleoanthropologist is by Daniel Lieberman. In an accompanying article in the same issue of Nature, he writes: “The evolutionary history of humans is complex and unresolved.” He goes on to say that this new skull makes things even more confusing.