Morphology of Ordovician-Devonian Crinoids PDF Download

Author: Mike Foote
Publisher:
ISBN:
Category : Crinoidea
Languages : en
Pages : 39

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Author: Hans Hess
Publisher: Cambridge University Press
ISBN: 9780521524407
Category : Nature
Languages : en
Pages : 310

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Crinoids have graced the oceans for more than 500 million years. Among the most attractive fossils, crinoids had a key role in the ecology of marine communities through much of the fossil record, and their remains are prominent rock forming constituents of many limestones. This is the first comprehensive volume to bring together their form and function, classification, evolutionary history, occurrence, preservation and ecology. The main part of the book is devoted to assemblages of intact fossil crinoids, which are described in their geological setting in twenty-three chapters ranging from the Ordovician to the Tertiary. The final chapter deals with living sea lilies and feather stars. The volume is exquisitely illustrated with abundant photographs and line drawings of crinoids from sites around the world. This authoritative account recreates a fascinating picture of fossil crinoids for paleontologists, geologists, evolutionary and marine biologists, ecologists and amateur fossil collectors.

Author: Raymond Cecil Moore
Publisher: Geological Society of America
ISBN: 081372046X
Category : Crinoidea, Fossil
Languages : en
Pages : 182

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Author: Thomas Edgar Guensburg
Publisher:
ISBN: 9780877104582
Category : Animals, Fossil
Languages : en
Pages : 43

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Six new primitive genera from the Early Ordovician of western Utah significantly advance our understanding of early crinoid history. Two of the new genera are the oldest crinoids (early Ibexian, early Tremadoc) and represent a previously unknown protocrinoid evolutionary grade, differing from other crinoids in having a nonstandardized dorsal cup and arms bearing ambulacral floor plates. Titanocrinus sumralli, new genus and species, has hundreds of unorganized mid-cup and interbrachial plates separating the cup-base basal circlet and the ray plates. Glenocrinus globularis, new genus and species, has similar plating with a more compact globular cup and fewer mid-cup plates, and is near the origin of diplobathrid camerates. A third taxon, Eknomocrinus wahwahensis, new genus and species, from the same lower stratigraphic interval, is a stem-group monocyclic camerate crinoid with standardized but irregular cup plating and other emergent crinoid traits shared with protocrinoids. Three new camerates from higher in the section are more derived. Cnemecrinus fillmorensis, new genus and species, and Habrotecrinus ibexensis, new genus and species, both latest Ibexian (middle Arenig), are monocyclic camerates. The latter taxon has unique accessory plates and major cup plate shapes. The fossil record indicates rapid diversification of disparid, cladid, and camerate crinoids by the end of the middle Ibexian (late Tremadoc), each arising independently from the protocrinoid stem group. Evidence from ontogeny, cup-stem and radial orientation, and now, early morphologic transitions necessitates revision of long used skeletal terminology. Dual ray and cup-base references for plate homologies, rather than the traditional ray-only model, are consistent with this evidence. Consequently, infrabasals are redefined as the cup-base circlet of both dicyclic and monocyclic crinoids. The use of basals is restricted to plates between infrabasals and radials of dicyclic (and tricyclic) crinoids. Traditional classifications emphasizing cup plate circlet number is unreliable early in the crinoid record; instead, posterior and interray cup morphology provides the most consistent phylogenetic information.

Author: James W. Valentine
Publisher: University of Chicago Press
ISBN: 9780226389110
Category : Science
Languages : en
Pages : 504

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Representing the state of the art in evolutionary paleobiology, this book provides a much-needed overview of this rapidly changing field. An influx of ideas and techniques both from other areas of biology and from within paleobiology itself have resulted in numerous recent advances, including increased recognition of the relationships between ecological and evolutionary theory, renewed vigor in the study of ecological communities over geologic timescales, increased understanding of biogeographical patterns, and new mathematical approaches to studying the form and structure of plants and animals. Contributors to this volume—a veritable who's who of eminent researchers—present the results of original research and new theoretical developments, and provide directions for future studies. Individually wide ranging, these papers all share a debt to the work of James W. Valentine, one of the founders of modern evolutionary paleobiology. This volume's unified approach to the study of life on earth will be a major contribution to paleobiology, evolution, and ecology.

Author: Jonathan M. Adrain
Publisher: Springer Science & Business Media
ISBN: 1461505712
Category : Science
Languages : en
Pages : 420

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Phylogenetic analysis and morphometrics have been developed by biologists into rigorous analytic tools for testing hypotheses about the relationships between groups of species. This book applies these tools to paleontological data. The fossil record is our one true chronicle of the history of life, preserving a set of macroevolutionary patterns; thus various hypotheses about evolutionary processes can be tested in the fossil record using phylogentic analysis and morphometrics. The first book of its type, Fossils, Phylogeny, and Form will be useful in evolutionary biology, paleontology, systematics, evolutionary development, theoretical biology, biogeography, and zoology. It will also provide a practical, researcher-friendly gateway into computer-based phylogenetics and morphometrics.

Author: Roland Emson
Publisher: CRC Press
ISBN: 9789054105961
Category : Science
Languages : en
Pages : 368

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This volume demonstrates the wide range of echinoderm research, from molecular genetics to palaeontology, in progress today. It features 45 papers on: biochemical and molecular studies; environmental monitoring; functional biology; palaeontology; development, growth and regeneration; and reproduction.

Author: Bradley Deline
Publisher: Cambridge University Press
ISBN: 1108898041
Category : Science
Languages : en
Pages : 79

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The quantification of morphology through time is a vital tool in elucidating macroevolutionary patterns. Studies of disparity require intense effort but can provide insights beyond those gained using other methodologies. Over the last several decades, studies of disparity have proliferated, often using echinoderms as a model organism. Echinoderms have been used to study the methodology of disparity analyses and potential biases as well as documenting the morphological patterns observed in clades through time. Combining morphological studies with phylogenetic analyses or other disparate data sets allows for the testing of detailed and far-reaching evolutionary hypotheses.

Author: Kyle Richard Womack
Publisher:
ISBN:
Category :
Languages : en
Pages : 192

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Crinoids are the most primitive living members of the Phylum Echinodermata. Though still present in reduced numbers today, crinoids were the dominant echinoderms from the Ordovician to the Permian. The crinoid body plan consists of three major regions, the column, the calyx, and the arms. Each region serves important functions in crinoids. The column raises the rest of the body into the water column for more efficient feeding. The calyx contains the visceral mass and mouth. Arms extend out from the top of the calyx to trap microorgansisms and suspended organic particles in the water column. A re-evaluation of these functional units is undertaken to understand the importance of various structures and to obtain discrete characters for use in a cladistic analysis. The relationship of crinoid crown groups has been an active area of research for the past couple of decades. With each proposed phylogenetic relationship, a new interpretation of thecal plate homology has been proposed. Here each study is re-examined in the light of new data. A review of functional morphology indicates a dual-reference system to be the most supported interpretation of plate homology. The two reference points in this system are the stem-cup and the cup-arm junctions, at the top and bottom of the calyx. The difference between a two-circlet and three-circlet crinoid is the presence or absence of the middle (basal) circlet. A new cladistic analysis is presented, with the topology of trees obtained giving support for the retention of Paleozoic crinoid stem and crown groups. Crinoids appear abruptly in the fossil record. Questions pertaining to origins and ancestral stock abound. A biogeography study is employed to look at the distribution of crinoids from the Early to Middle Ordovician. Locality information, combined with an understanding of the movement of major plates, paleoclimate data, an understanding of larval distribution, and a review of similar studies carried out on different taxa, gives insight into possible radiation and dispersal patterns of crinoids from the first half of the Ordovician.

Author: Winifred Goldring
Publisher:
ISBN:
Category : Crinoidea, Fossil
Languages : en
Pages : 812

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