Cetacean Paleobiology

Cetaceans (whales, dolphins, and porpoises) have fascinated and bewildered humans throughout history. Their mammalian affinities have been long recognized, but exactly which group of terrestrial mammals they descend from has, until recently, remained in the dark. Recent decades have produced a flurry of new fossil cetaceans, extending their fossil history to over 50 million years ago. Along with new insights from genetics and developmental studies, these discoveries have helped to clarify the place of cetaceans among mammals, and enriched our understanding of their unique adaptations for feeding, locomotion and sensory systems. Their continuously improving fossil record and successive transformation into highly specialized marine mammals have made cetaceans a textbook case of evolution - as iconic in its own way as the origin of birds from dinosaurs. This book aims to summarize our current understanding of cetacean evolution for the serious student and interested amateur using photographs, drawings, charts and illustrations.

Auteur

Felix G. Marx is Curator Vertebrates at the Museum of New Zealand Te Papa Tongarewa, where he primarily looks after the marine mammal collection. Prior to becoming a curator, he spent several years as a postdoctoral fellow in Australia, Belgium and Japan. He specialises in the evolution of baleen whales, but has worked on a broad variety of topics, from macroevolution to feeding ecology, biogeography, and behaviour.

Dr Olivier Lambert is a vertebrate palaeontologist at the Institut royal des Sciences naturelles de Belgique, Brussels. Interested in the secondary adaptations of mammals to the marine environment, Dr Lambert studies fossil cetaceans from many geological ages and localities in the world. Most of his publications focus on extinct echolocating toothed whales, especially from the North Atlantic and South-East Pacific realms.

Dr Mark D. Uhen is an Assistant Professor of Geology at George Mason University. Dr Uhens research focuses on the origin and evolution of cetaceans (whales and dolphins), and other marine mammals. He has conducted field work around the world, developed exhibits and lessons on cetacean evolution for museums, and published on his work in journals, and books. Dr Uhen is also a leader of the Paleobiology Database, an on-line open resource that documents every fossil occurrence on the planet.

Contenu

Series Editor's Preface vii

Preface viii

Acknowledgments x

1 Cetaceans, Past and Present 1

1.1 Introduction and scope of the book 1

1.2 What is a whale? 2

1.3 Diversity, distribution, and ecology of modern cetaceans 3

1.4 How to study extinct cetaceans 5

1.4.1 Comparative and functional anatomy 5

1.4.2 Evolutionary relationships 6

1.4.3 Habitat and feeding preferences 9

1.4.4 Macroevolutionary dynamics 11

1.4.5 Other methodologies 13

1.5 Suggested readings 13

References 13

2 Cetacean Fossil Record 19

2.1 A history of exploration 19

2.2 Strengths and weaknesses of the cetacean fossil record 23

2.2.1 Preservation potential 23

2.2.2 Biases affecting fossil recovery 24

2.2.3 Outlook 27

2.3 Major fossil localities 28

2.3.1 Tethys 28

2.3.2 North Atlantic 30

2.3.3 South Atlantic 32

2.3.4 North Pacific 32

2.3.5 South Pacific 33

2.3.6 Dredge sites: South Africa and Iberia 35

2.4 Suggested Readings 35

References 35

3 Morphology 44

3.1 Overview 44

3.2 The skull 46

3.2.1 Rostrum and central facial region 46

3.2.2 Forehead, skull vertex, and posterior cranium 50

3.2.3 Temporal fossa and basicranium 54

3.2.4 Periotic 56

3.2.5 Tympanic bulla 63

3.2.6 Auditory ossicles 64

3.2.7 Dentition 65

3.2.8 Mandible 66

3.2.9 Hyoid apparatus 67

3.3 The postcranial skeleton 68

3.3.1 Vertebral column and rib cage 68

3.3.2 Forelimb 70

3.3.3 Hind limb 73

3.4 Osteological correlates of soft tissue anatomy 74

3.4.1 Musculature 74

3.4.2 Baleen 79

3.4.3 Air sinus system, air sacs and fat pads 79

3.4.4 Brain anatomy and cranial nerves 80

3.4.5 Sensory organs 84

3.4.6 Flukes 86

3.5 Suggested readings 87

References 87

4 Phylogeny and Taxonomy 95

4.1 Cetacean origins 95

4.2 The earliest whales: archaeocetes 97

4.2.1 Pakicetids, ambulocetids, and remingtonocetids 97

4.2.2 Protocetidae and basal Pelagiceti 99

4.3 Filterfeeding whales: Mysticeti 102

4.3.1 Toothed mysticetes 103

4.3.2 Toothless mysticetes 106

4.4 Echolocating whales: Odontoceti 114

4.4.1 Stem odontocetes 115

4.4.2 Potential crown odontocetes 119

4.4.3 Basal crown odontocetes 122

4.4.4 Delphinida 130

4.4.5 Crown Delphinoidea 136

4.5 Consensus, conflicts, and diversification dates 141

4.5.1 Highlevel conflicts and possible solutions 141

4.5.2 Divergence dates 142

4.6 Suggested readings 145

References 145

5 Major Steps in the Evolution of Cetaceans 157

5.1 From land to sea: the last steps 157

5.1.1 Initial forays into the water 157

5.1.2 Transition to marine environments 162

5.1.3 Divorce from land 169

5.2 Key innovations: baleen and echolocation 171

5.2.1 Baleen 171

5.2.2 Echolocation 174

5.3 Invasion of freshwater habitats 176

5.4 Key fossils 180

5.4.1 Archaeocetes 180

5.4.2 Mysticeti 183

5.4.3 Odontoceti 186

5.5 Suggested readings 189

References 189

6 Fossil Evidence of Cetacean Biology 198

6.1 Feeding strategies 198

6.1.1 Archaeocetes 198

6.1.2 Mysticeti 203

6.1.3 Odontoceti 211

6.2 Cetaceans as a source of food 217

6.2.1 Active predation 217

6.2.2 Whale falls 218

6.3 Reproduction 220

6.4 Migration 222 6.5 Sexual...