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 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.