How Vertebrates Left the Water

Contents

Dipnoans: Our Closest Extant Finned Cousins ... 49 Reproduction among Tetrapods: Amphibians Are Not All Amphibious! ... 51 three Paleontological Context . . . 55 The Conquest of Land in Various Taxa ... 55 The History of Our Ideas about the Conquest of Land by Vertebrates ... 63 The Lateral-Line Organ and the Lifestyle of Paleozoic Stegocephalians ... 68 four Vertebrate Limb Evolution . . . 73 The Vertebrate Skeleton ... 73 Hox Genes and the Origin of Digits ... 75 Sarcopterygian Fins and the Origin of Digits ... 79 Fragmentary Fossils, Phylogeny, and the First Digits ... 82 The Gills of Acanthostega and the Original Function of the Tetrapod Limb ... 88 Bone Microanatomy and Lifestyle ... 89 five Diversity of Paleozoic Stegocephalians . . . 99 Temnospondyls ... 99 Embolomeres ... 106 Seymouriamorphs ... 109 Amphibians ...116 Diadectomorphs ...121 Amniotes ... 125 Stegocephalian Phylogeny ... 127 six Adaptations to Life on Land . . . 135 Limbs and Girdles ... 136 Vertebral Centrum and Axial Skeleton ... 140 Breathing ... 142 The Skin and Water Exchange ... 147 Sensory Organs ... 150 seven Synthesis and Conclusion . . . 161 Conquest of Land and the First Returns to the Aquatic Environment ... 161 Why Come onto Land? ... 163 Modern Paleontology and the “Indiana Jones” Stereotype ... 166 Glossary ... 169 Bibliography ... 175 Index ... 187 This page intentionally left blank ...