“Speciation remains the special case, the less frequent and more elusive phenomenon, often arising by default” (p 164).1
Over the last thirty years, great progress has been made regarding our understanding of Homo sapiens evolution in Africa and, in particular, the origin of anatomically modern humans. However, in the mid-1970s, the whole process of Homo sapiens evolution in Africa was unclear and confusing. At that time it was widely assumed that very archaic-looking hominins, also called the “Rhodesioids,” which included the specimens from Kabwe (Zambia), Saldanha (South Africa), and Eyasi (Tanzania), were spread over wide parts of the continent as recently as 30,000 or 40,000 years ago. Yet, at the same time, there were also indications from the Omo Kibish skeletal remains (Ethiopia) and the Border Cave specimens (South Africa) that anatomically modern humans had already been present somewhat earlier than 100,000 years B.P.2, 3 Thus, it was puzzling how such early moderns could fit in with the presence of very archaic humans still existing in Eastern and Southern Africa only 30,000 years ago.