Mammal-Like Reptiles and the Origins of Mammals

The synapsid, or mammal-like, reptiles are the group from which the mammals evolved. They have left an excellent fossil record, and in recent years new localities have yielded important new specimens, while new techniques for the preparation of fossils have led to a great increase in our knowledge of hitherto rather poorly known forms. This book reviews the various groups of mammal-like reptiles and their early mammalian descendants, not only in terms of their geological occurrence, structure and phylogenetic relationships, but also their functional anatomy and what is known of their general biology and palaeo-ecology. Existing ideas and current controversies are discussed, and frequently new hypotheses based on up-to-date information are proposed. The fossil record of the mammal-like reptiles is also viewed as a whole, as an example of an extended phase of macro-evolution, and as an illustration of the origin of a major higher taxon, the Mammalia. The biological significance of the pattern and sequence of acquisition of mammalian features is discussed, and related to the development of the high level of homeostasis characteristic of the mammals. The overall pattern of evolution is treated in the light of contemporary ideas about interpretation of the fossil record. The possible significance of such concepts as punctuated equilibria, species turnover, mass-extinction and internal factors in the search for underlying causes of evolutionary pattern is discussed. In order to reduce the amount of purely verbal description, extensive use has been made of illustrations, both new ones, and those taken from the literature. Anyone interested in palaeontology, evolution or comparative vertebrate biology will find this book fascinating, but it will be particularly useful to research zoologists and palaeontologists.