List of boxes viii

Preface x

About the companion website xii

1 Vertebrates Originate 1

Key questions in this chapter 2

Introduction 2

1.1 Sea squirts and the lancelet 2

1.2 Ambulacraria: echinoderms and hemichordates 4

1.3 Deuterostome relationships 6

1.4 Chordate origins 8

1.5 Vertebrates and the head 14

1.6 Further reading 14

Questions for future research 15

1.7 References 15

2 How to Study Fossil Vertebrates 18

Key questions in this chapter 19

Introduction 19

2.1 Digging up bones 19

2.2 Publication and professionalism 24

2.3 Geology and fossil vertebrates 29

2.4 Biology and fossil vertebrates 33

2.5 Discovering phylogeny 36

2.6 The quality of the fossil record 39

2.7 Macroevolution 41

2.8 Further reading 43

2.9 References 43

3 Early palaeozoic fishes 45

Key questions in this chapter 46

Introduction 46

3.1 cambrian vertebrates 46

3.2 vertebrate hard tissues 49

3.3 the jawless fishes 51

3.4 origin of jaws and gnathostome relationships 59

3.5 placoderms: armour-plated monsters 60

3.6 chondrichthyes: the first sharks 65

3.7 acanthodians: the 'spiny skins' 65

3.8 devonian environments 67

3.9 osteichthyes: the bony fishes 70

3.10 early fish evolution and mass extinction 79

3.11 further reading 79

Questions for future research 80

3.12 References 80

4 Early tetrapods and amphibians 84

Key questions in this chapter 85

Introduction 85

4.1 Problems of life on land 85

4.2 Devonian tetrapods 88

4.3 The Carboniferous world 96

4.4 Diversity of Carboniferous tetrapods 98

4.5 Temnospondyls and reptiliomorphs after the Carboniferous 106

4.6 E volution of the modern amphibians 109

4.7 Further reading 114

Questions for future research 114

4.8 References 114

5 Evolution of early amniotes 118

Key questions in this chapter 119

Introduction 119

5.1 Hylonomus and Paleothyris - biology of the first amniotes 119

5.2 Amniote evolution 121

5.3 The Permian world 125

5.4 The parareptiles 125

5.5 The eureptiles 128

5.6 Basal synapsid evolution 132

5.7 The Permo-Triassic mass extinction 142

5.8 Further reading 143

Questions for future research 143

5.9 References 143

6 Bounceback: tetrapods of the Triassic 147

Key questions in this chapter 148

Introduction 148

6.1 The Triassic world and its effect on the recovery of life 148

6.2 Triassic marine reptiles 150

6.3 E volution of the archosauromorphs 154

6.4 O rigin of the dinosaurs 161

6.5 Reptile evolution in the Triassic 164

6.6 Further reading 168

Questions for future research 168

6.7 References 168

7 Evolution of fishes after the devonian 172

Key questions in this chapter 173

Introduction 173

7.1 The early sharks and chimaeras 173

7.2 Post-Palaeozoic chondrichthyan radiation 178

7.3 The early bony fishes 181

7.4 Radiation of the teleosts 191

7.5 Post-Devonian evolution of fishes 198

7.6 Further reading 199

Questions for future research 199

7.7 References 199

8 The age of d