Forerunners of Mammals: Radiation, Histology, Biology

The Great Karoo Basin of South Africa is a treasure-house of fossils that document in exquisite detail several important evolutionary lineages spanning almost 110 million years of geological time, from the Mid-Permian to the Early Jurassic - a fact still known to surprisingly few South Africans. One particular line whose history the Karoo rocks guard so carefully is the one from which we ourselves are descended: the one leading to the mammals. From its earliest beginnings in Late Carboniferous times, to the emergence of the first true mammals in the Late Triassic or Early Jurassic, each major step is recorded in the un-matched fossil record of the Karoo Supergroup. Wits University's Professor Bruce Rubidge, one of the leading investigators of this span of geological time, is fond of saying that you cannot write a textbook about the evolution of vertebrate life on Earth without extensive reference to the South African Karoo. And what is contained in this book underscores the truth of Rubidge's assertion.