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Author: Kyle Richard Womack Publisher: ISBN: Category : Languages : en Pages : 192
Book Description
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: Kyle Richard Womack Publisher: ISBN: Category : Languages : en Pages : 192
Book Description
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: Bradley L. Deline Publisher: ISBN: Category : Languages : en Pages : 84
Book Description
Crinoid columnals are a major constituent in the Upper Ordovician fossil assemblage of the Cincinnati Arch Region. Several species of Cincinnatian crinoids are identifiable based on columnal morphology alone. Disarticulated columnals of two crinoids were measured throughout a 68-meter section of the Kope and lower Fairview Formations to examine the relationship between columnal morphology and sea level fluctuations. The columnal diameter of two disparid crinoids increased in the upward shallowing sequence. Detrended Correspondence Analysis axis 1 scores computed using columnal measurements of two crinoids correlated significantly with a proxy for depth. Therefore, crinoid columnals may provide a metric for the study of small-scale sea level fluctuation in a depositional sequence. A larger scale study showed similar morphological shifts in five taxa of crinoids, but to differing degrees. The morphologic shifts in the columnals are likely due to differences in nutrient levels and flow regimes between depths.
Author: Hans Hess Publisher: Cambridge University Press ISBN: 9780521524407 Category : Nature Languages : en Pages : 310
Book Description
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: William I. Ausich Publisher: Indiana University Press ISBN: 0253351286 Category : Science Languages : en Pages : 474
Book Description
The dominant faunal elements in shallow Paleozoic oceans, echinoderms are important to understanding these marine ecosystems. Echinoderms (which include such animals as sea stars, crinoids or sea lilies, sea urchins, sand dollars, and sea cucumbers) have left a rich and, for science, extremely useful fossil record. For various reasons, they provide the ideal source for answers to the questions that will help us develop a more complete understanding of global environmental and biodiversity changes. This volume highlights the modern study of fossil echinoderms and is organized into five parts: echinoderm paleoecology, functional morphology, and paleoecology; evolutionary paleoecology; morphology for refined phylogenetic studies; innovative applications of data encoded in echinoderms; and information on new crinoid data sets.
Author: J. Michael Parrish Publisher: Indiana University Press ISBN: 0253009472 Category : Science Languages : en Pages : 313
Book Description
Drawn from a 2005 international symposium, these essays explore current tyrannosaurid current research and discoveries regarding Tyrannosaurus rex. The opening of an exhibit focused on “Jane,” a beautifully preserved tyrannosaur collected by the Burpee Museum of Natural History, was the occasion for an international symposium on tyrannosaur paleobiology. This volume, drawn from the symposium, includes studies of the tyrannosaurids Chingkankousaurus fragilis and “Sir William” and the generic status of Nanotyrannus; theropod teeth, pedal proportions, brain size, and craniocervical function; soft tissue reconstruction, including that of “Jane”; paleopathology and tyrannosaurid claws; dating the “Jane” site; and tyrannosaur feeding and hunting strategies. Tyrannosaurid Paleobiology highlights the far ranging and vital state of current tyrannosaurid dinosaur research and discovery. “Despite being discovered over 100 years ago, Tyrannosaurus rex and its kin still inspire researchers to ask fundamental questions about what the best known dinosaur was like as a living, breathing animal. Tyrannosaurid Paleobiology present a series of wide-ranging and innovative studies that cover diverse topics such as how tyrannosaurs attacked and dismembered prey, the shapes and sizes of feet and brains, and what sorts of injuries individuals sustained and lived with. There are also examinations of the diversity of tyrannosaurs, determinations of exactly when different kinds lived and died, and what goes into making a museum exhibit featuring tyrannosaurs. This volume clearly shows that there is much more to the study of dinosaurs than just digging up and cataloguing old bones.” —Donald M. Henderson, Royal Tyrrell Museum of Palaeontology
Author: David D. Gillette Publisher: Utah Geological Survey ISBN: 1557916349 Category : Nature Languages : en Pages : 568
Book Description
The 52 papers in this vary in content from summaries or state-of-knowledge treatments, to detailed contributions that describe new species. Although the distinction is subtle, the title (Vertebrate Paleontology in Utah) indicates the science of paleontology in the state of Utah, rather than the even more ambitious intent if it were given the title “Vertebrate Paleontology of Utah” which would promise an encyclopedic treatment of the subject. The science of vertebrate paleontology in Utah is robust and intense. It has grown prodigiously in the past decade, and promises to continue to grow indefinitely. This research benefits everyone in the state, through Utah’s muse ums and educational institutions, which are the direct beneficiaries.
Author: Peter C. Wainwright Publisher: University of Chicago Press ISBN: 0226869954 Category : Science Languages : en Pages : 375
Book Description
Ecological morphology examines the relation between an animal's anatomy and physiology—its form and function—and how the animal has evolved in and can inhabit a particular environment. Within the past few years, research in this relatively new area has exploded. Ecological Morphology is a synthesis of major concepts and a demonstration of the ways in which this integrative approach can yield rich and surprising results. Through this interdisciplinary study, scientists have been able to understand, for instance, how bat wing design affects habitat use and bat diet; how the size of a predator affects its ability to capture and eat certain prey; and how certain mosquitoes have evolved physiologically and morphologically to tolerate salt-water habitats. Ecological Morphology also covers the history of the field, the role of the comparative method in studying adaptation, and the use of data from modern organisms for understanding the ecology of fossil communities. This book provides an overview of the achievements and potential of ecological morphology for all biologists and students interested in the way animal design, ecology, and evolution interact.
Author: Donald B. Brinkman Publisher: Springer Science & Business Media ISBN: 9400743084 Category : Science Languages : en Pages : 577
Book Description
This volume celebrates the contributions of Dr. Eugene Gaffney to the study of turtles, through a diverse and complementary collection of papers that showcases the latest research on one of the most intriguing groups of reptiles. A mix of focused and review papers deals with numerous aspects of the evolutionary history of turtles, including embryonic development, origins, early diversification, phylogenetic relationships, and biogeography. Moreover it includes reports on important but poorly understood fossil turtle assemblages, provides historical perspectives on turtle research, and documents disease and variation in turtles. With its broad scope, which includes descriptions of material and new taxa from Australia, Asia, and Europe, as well as North and South America, this work will be an essential resource for anyone interested in the morphology and evolution of turtles. “This volume’s breadth of time, geography, and taxonomic coverage makes it a major contribution to the field and a ‘must have’ for all vertebrate paleontologists.”, James F. Parham, California State University, CA, USA “A comprehensive and sweeping overview of turtle evolution by the top experts in the field that will interest everyone curious about these unique reptiles.” Jason S. Anderson, University of Calgary, Canada “An invaluable addition to the literature that covers the full spectrum of approaches toward understanding the evolution of these noble creatures.” Ann C. Burke, Wesleyan University, CT , USA “A truly comprehensive volume that both the student of fossil turtles, as well as the general reader interested in these enigmatic creatures, will find fascinating.” Tyler Lyson, Yale University, CT, USA
Author: Kyle Richard Womack
Author: Kyle Richard Womack
Author: Bradley L. Deline
Author: Francis Arthur Bather
Author: Hans Hess
Author: William I. Ausich
Author: Raymond Cecil Moore
Author: J. Michael Parrish
Author: David D. Gillette
Author: Peter C. Wainwright
Author: Donald B. Brinkman