Mammalian Evidence Concerning the Eocene-Oligocene Transition in Europe, North America and Asia

Abstract

This chapter presents mammalian evidence concerning the Eocene–Oligocene transition in Europe, North America, and Asia. In North America, the mammalian faunas of the late Eocene- early Oligocene transition are those characterizing the Uintan, Duchesnean, and Chadronian land-mammal ages. Mammalian evolution indicates that in North America particularly high rates of change were maintained over a period of at least 10 million years; the Eocene–Oligocene boundary was situated near the middle of this time. In Europe, a peak of extinctions occurred in the Late Eocene (as it did in Asia); after a low point in the Late Eocene (also as in Asia) a maximum of new genera appeared in Europe with the Early Oligocene. Information from Asia is less abundant than it is from Europe or North America, but considerable progress has been made in recent years. Perissodactyls in the Paleogene of Asia display abundance, in both numbers and taxa that is unequaled elsewhere. This is particularly true of the middle Eocene; in the late Eocene they diminish somewhat but still retain a diversity that is superior to that of the artiodactyls.