21 - Amphibians, reptiles and birds: a biogeographical review

Summary

INTRODUCTION

This chapter reviews briefly the apparent responses to global events by the amphibians, reptiles and birds during the past 145 million years. The vast majority of living members of these groups are terrestrial or freshwater (aquatic or amphibious) dwellers. Some 4956 species of amphibians are represented by 28 families of Anura (frogs and toads), ten families of Caudata (newts and salamanders) and five families of Gymnophiona (caecilians) (Cogger & Zweifel, 1998). Over 7427 living species of reptiles are represented by 13 families of Testudinata (turtles and tortoises), 48 families of Lepidosauromorpha (comprising 26 lizard families, ca. 18 snake families, 4 amphisbaenid (worm lizard) families and a single relict rhynchocephalian genus, the Tuatara (Sphenodon)) and the Archosauria (Coggar & Zweifel, 1998). The last group includes the extinct Pterosauria and the wholly terrestrial Dinosauria, and is today represented by three families of Crocodylia (crocodiles and alligators) and by the birds, the most numerous terrestrial vertebrates with over 9700 species in more than 20 orders, more than 50% belonging to the Passeriformes (song birds) (Feduccia, 1996).

The geographical distribution patterns of these groups are intimately linked to the historical distribution of continental areas, and we can attempt to relate the patterns of their past and present distributions to the patterns produced by the global dynamics of plate tectonics. An understanding of the patterns of relationships within these (and other) groups of organisms is fundamental to attempts to interpret their vicariance and dispersal patterns.