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PALAEOZOIC VERTEBRATE BIOSTRATIGRAPHY and BIOGEGRAPHY |
PREFACE John A. Long The study of Palaeozoic vertebrates has long been an integral part of understanding the evolution and anatomy of the lower back-boned animals. However the use of Palaeozoic fishes in geological correlation's has also been long known, at least since the time of Hugh Miller, in the early nineteenth century, when Old Red Sandstone fish fossils were used to identify the same series of rocks, of approximately the same age, around different parts of Scotland. In the last twenty or so years there has been an upsurge in the study of Palaeozoic fishes for solving geological problems, both in areas of biostratigraphy and biogeography. This has resulted in an explosion of new data, much of it so new that it will take years for all the recent discoveries to be published. This book has resulted to fill the need to provide up-to-date summaries of global work in progress showing the applications of both macroscopic and microscopic remains of Palaeozoic vertebrates to geological correlations, and to refinement of global palaeogeographic reconstructions. It is, of course, a bit ambitious to try and tackle the entire world perspective in this manner, so selections have been made to cover the major Palaeozoic terranes in which vertebrate fossils are proving to be very useful. Many of the chapters in this book are contributions to UNESCO International Geological Correlation Project 328 (Project leaders: Sue Turner and Gavin Young), a testimony to the recognition of the international importance of developing studies of Palaeozoic vertebrate biostratigraphy. The main problems with this book are its limitations in trying to provide both accurate summaries of the subject areas and ample illustrations showing the morphology of the most useful species. In many cases, work coming from China, Australia, South America, Siberia, and the Middle East is so new that schemes presented here are only progress reports of better things to come. However, the value of this data-co have in the hand now-will be invaluable to the many new workers around the world who are starting an involvement in IGCP 328, or to geologists who have turned to Palaeozoic vertebrates for solving problems of local correlation, age assessment or palaeoenvironmental interpretation. The focus of the chapters in this volume is largely on the new discoveries of Palaeozoic vertebrates in successions that are well-constrained by other Preface dating methods, and thus may be correlatable with either microfossil zonations or marine invertebrates and microfossil zonation schemes. Palaeogeographic uses of Palaeozoic vertebrates have been refined in recent years in accord with refinements in palaeogeographic reconstructions. By using distribution hypotheses, data from fossil fishes can be tested against other geological hypotheses to refine biogeographic and tectonic models. Part One gives the background information necessary to utilise the summaries of biostratigraphic and biogeographic data provided in the rest of the book. Chapter 1 gives an introduction to the basic morphology of Palaeozoic vertebrates, providing a simple guide to the nature of their fossilised hard-parts (skeletal remains). In many cases the correlative value of a Palaeozoic vertebrate may lie in finding one scale or tooth from a drillcore sample. This chapter outlines the overall features of each major vertebrate group, and defines their biostratigraphically useful parts. Chapter 2 gives the latest Palaeozoic global reconstructions using new palaeomagnetic data, and using a `filter system' on old palaeomagnetic data. This has a screening effect on preventing old, potentially unreliable palaeomagnetic data from distorting the global reconstruction. Chapter 3 is a short summary of major extinction events for Early-Middle Palaeozoic vertebrates. The heart of useful biostratigraphic methodology is identifying the constraints on age range of a taxonomically distinctive group or species. Extinction events, even minor ones, provide useful datum points to frame groupings of minor biostratigraphic events. Part Two gives summaries of biostratigraphic schemes for the major Palaeozoic vertebrate provinces. I asked each author to provide the latest charts of age ranges, give a discussion of palaeoenvironmental settings and tie in vertebrate occurrences with other reliable dating criteria, such as marine invertebrate or microfossil occurrences. This has largely been achieved and useful summary charts have been provided throughout Part Two. The classic localities of the Old Red Continent (Euramerica) have been divided into agnathan faunas (Chapter 4) and gnathostomes (Chapter 6). The faunas of Siberia and neighbouring terranes are summarised in Chapter 5, and those of Western Gondwana, covering South America, Africa, Spain and parts of the Middle East, are dealt with in Chapter 7. The wealth of new discoveries coming from Australia, Antarctica and Asia are covered by Chapters 8-11. Part Three of this book gives two overviews of Palaeozoic vertebrate biogeography. Chapter 12 covers the definition of, and associated problems with, Middle Palaeozoic faunal provinces-why some groups of Siluro-Devonian fishes show high endemism while others are cosmopolitan. The age ranges of many biostratigraphically useful forms are shown to be intimately linked to their phylogenetic history and possible `centres of diversification'. Chapter 13 is the only chapter of the book treating tetrapods, and discusses how land-dwelling amphibians and reptiles achieved global dispersal, and outlines the value of tetrapods to defining faunal provinces in the Late Palaeozoic. I apologise to readers for the lack of coverage of Late Palaeozoic fish assemblages. Much of this work is in progress, and it was unfortunate that the several workers whom I approached to write on this subject were unable to contribute. Biostratigraphy is an integral aspect of palaeontology that requires continual refinement and modification of existing schemes as new data comes to hand. Unlike many of the currently used invertebrate zone fossils, many Palaeozoic fish species can occur in transitional environments the one species inhabiting marine, near shore and/or terrestrial facies. This means that the opportunity to link established marine invertebrate or microfossil zones with terrestrial sequences is largely the domain of Palaeozoic vertebrates and palynology (the study of spores and pollen). For this reason it is important to continually take stock of new work, and make an effort to summarise progress and outline problematic areas. I hope that both researchers and students find this book useful in more ways than as a summary of latest work, and also trust that it will provide stimulus for ideas of how improvements can be made to future biostratigraphic schemes. It cannot be emphasised too much that good biostratigraphy relies on three factors: (1) a solid foundation of good taxonomy-correct identification of zone species and an understanding of the anatomical basis for biostratigraphic zone fossils; (2) careful collecting and preparation procedures-precise laboratory practises; and (3) an integrated geological/stratigraphical approach (understanding the geological and tectonic settings of the sample locations). The chapters in this book give numerous examples of the dating and correlation of geological strata throughout the world using Palaeozoic vertebrate remains. However, there is much work to be done before the numerous discoveries of new Palaeozoic vertebrates are described and then integrated into biostratigraphic schemes. I sincerely hope this book provides the necessary guidelines and inspiration for more students to become involved in studies on lower vertebrate fossils, and for petroleum and gas exploration companies to realise the huge potential for improved correlations and palaeoenvironmental interpretations that Palaeozoic fishes can contribute. This book arose from a discussion with Ken McNamara who had been talking with Iain Stevenson of Belhaven Press. I would like to thank Ken for his encouragement and continual advice on this project as it unfolded, and Iain Stevenson for his receptive support in getting the book off the ground. The Trustees of the Western Australian Museum provided facilities for carrying out research for my chapters, and to edit this book. Special thanks to Kris Brimmell, W.A. Museum for her technical support. Finally, I give my heartiest thanks to each author for their excellent contributions and lack of tardiness in providing the chapters. If not for my three month trip to Antarctica over the summer season of 1991 /92 this book would have been ready some months earlier, and I apologise to the authors for my own delay in this matter. |
CONTENTS List of figures List of tables List of contributors Preface J.A. Long PART ONE Morphology, Tectonic Setting and Extinctions of Palaeozoic Vertebrates Chapter 1 - Morphological characteristics of Palaeozoic vertebrates used in biostratigraphy J.A. Long Chapter 2 - Palaeozoic global reconstructions Li, Z.X., C. McA. Powell and A. Trench Chapter 3 - Early-Middle Palaeozoic vertebrate extinction events J.A. Long PART TWO Palaeozoic Vertebrate Biostratigraphy Chapter 4 - The Silurian-Devonian agnathan biostratigraphy of the Old Red Continent P. Janvier and A. Blieck Chapter 5 - Silurian-Devonian vertebrate biostratigraphy of Siberia and neighbouring terranes A. Blieck and P. Janvier Chapter 6 - Biostratigraphy of the Silurian and Devonian gnathostomes of the Euramerica Province D. Dineley and E. Loeffler Chapter 7 - Silurian-Devonian vertebrate biostratigraphy of Western Gondwana and related terranes (South America, Africa, Armorica-Bohemia, Middle East) H. Lelievre, P. Janvier and A. Blieck Chapter 8 - Palaeozoic microvertebrate biostratigraphy of Eastern Gondwana S. Turner Chapter 9 - Middle Palaeozoic macrovertebrate biostratigraphy of Eastern Gondwana G. C. Young Chapter 10 - Vertebrate biostratigraphy of the Middle Palaeozoic of China Wang, S.-T. Chapter 11 - Palaeozoic vertebrate biostratigraphy of South-East Asia and Japan J.A. Long PART THREE Palaeozoic Vertebrate Biogeography Chapter 12 - Vertebrate faunal provinces in the Middle Palaeozoic G. C. Young Chapter 13 - Biogeography of Palaeozoic tetrapods A.R. Milner Systematic index Stratigraphic and locality index |
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