New Interpretations of Ape and Human Ancestry

Abstract

PrefaceIn the field of paleoanthropology there is perhaps no more compelling issue than the origin of the human lineage. From the 19th-Century proclamations of Darwin, Huxley, and Haeckel up to the present-day announcements of authorities such as Pilbeam, Johanson, and Leakey, controversy and debate have always surrounded the search for our earliest ancestors. Most authorities now agree that many important questions concerning ape and human ancestry will be solved by further investigation of the hominoid primates of the Miocene and Pliocene, and through exacting comparative anatomical and biomolecular analyses of their living representatives. Indeed, these studies will yield a better understanding of (1) the cladogenesis (branching order) of the hominoid primates, (2) the morphotype (structural components) of the last common ancestor of humans and the living apes, (3) the timing and geographical placement of the hominid-pongid (human-ape) divergence and (4) the adaptive nature and probable scenario for the initial differentiation of hominids from pongids.In this context we organized a symposium entitled "Miocene Hominoids and New Interpretations of Ape and Human Ancestry" which met July 2-4, 1980, in Florence, Italy,just prior to the convening of the VIII Congress ofthe International Primatological Society. This Pre-Congress Symposium was attended by a small group of anthropologists, anatomists, biochemists, ecologists, and paleontologists, all dedicated to a reanalysis of the evolutionary position and a more parsimonious interpretation of the Miocene hominoids vis a vis modern apes and humans. The symposium was held in the 18th-Century Tribuna di Galileo of the Istituto di Zoologia. Under the arched marble columns of this magnificent chamber, symposium participants were able to address specifically some or all of the points mentioned above. From this symposium a consensus was reached concerning a rapprochement between the formerly irreconcilable biomolecular view of human origins and the paleontological view. This rapprochement was based on a more liberal presentation of the "molecular clock hypothesis" and on the view that no known Miocene hominoid including Ramapithecus could be considered a hominid, that is, an exclusively human ancestor. xiii xiv PREFACE The Pre-Congress Symposium held in Florence was a rather small gathering, representing less than half of the contributors to this volume. Yet we feel that events at this symposium in many ways foreshadowed developments and trends in the field of paleoanthropology still underway. With the symposium behind us we began in earnest to assemble contributions for the present volume. About this time a number of additional leading authorities, who had not been able to attend the symposium, agreed to contribute chapters to the volume. We also decided to enlarge the scope of the volume to include contributions on Oligocene hominoid ancestors and on Plio-Pleistocene hominoid and hominid descendants. The central theme of the volume, however, remained the Hominoidea of th...