Ontogeny Intraspecific Variation And Systematics Of The Late Cambrian Trilobite Dikelocephalus PDF Download
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Author | : Nigel C. Hughes |
Publisher | : |
Total Pages | : 728 |
Release | : 1994 |
Genre | : Science |
ISBN | : |
Download Ontogeny, Intraspecific Variation, and Systematics of the Late Cambrian Trilobite Dikelocephalus Book in PDF, ePub and Kindle
Biometric analyses of well-localized specimens of the trilobite Dikelocephalus from the St. Lawrence Formation (Upper Cambrian), northern Mississippi Valley, suggest that all specimens belong to a single, highly variable morphospecies, D. minnesotensis. A complex pattern of ontogenetically-related and ontogeny-independent variation produced a mosaic of morphotypes, which show greater diversity than previously recorded within trilobite species. There is considerable variation within collections made from single beds. Variations of characters among collections are mosaic, and are clinal in some cases. Patterns of variation within Dikelocephalus cannot be related to lithofacies occurrence. There are no obvious temporal variations in D. minnesotensis within the St. Lawrence Formation, but some Dikelocephalus from the underlying Tunnel City Group may belong to a different taxon. The validity of this early taxon is questionable due to a lack of available material. The mosaic pattern of variation in Dikelocephalus mimics that documented at higher taxonomic levels in primitive libristomate trilobites, and helps explain difficulties in providing a workable taxonomy of primitive trilobites. Results caution proposition of evolutionary scenarios that do not take account of intraspecific variation. The recovery of dorsal shields of Dikelocephalus permits the first detailed reconstruction of the entire exoskeleton. The systematics of the genus is revised and twenty-five species are suppressed as junior synonyms of D. minnesotensis.
Author | : Robert Riding |
Publisher | : Columbia University Press |
Total Pages | : 540 |
Release | : 2001 |
Genre | : Nature |
ISBN | : 9780231106139 |
Download The Ecology of the Cambrian Radiation Book in PDF, ePub and Kindle
The Cambrian radiation was the explosive evolution of marine life that started 550,000,000 years ago. It ranks as one of the most important episodes in Earth history. This key event in the history of life on our planet changed the marine biosphere and its sedimentary environment forever, requiring a complex interplay of wide-ranging biologic and nonbiologic processes. The Ecology of the Cambrian Radiation offers a comprehensive and surprising picture of the Earth at that ancient time. The book contains contributions from thirty-three authors hailing from ten countries and will be of interest to paleontologists, geologists, biologists, and other researchers interested in the global Earth-life system.
Author | : P.J. Brenchley |
Publisher | : CRC Press |
Total Pages | : 432 |
Release | : 2023-07-14 |
Genre | : Science |
ISBN | : 1000939405 |
Download Palaeoecology Book in PDF, ePub and Kindle
The first palaeoecology book to focus on evolutionary palaeoecology, in both marine and terrestrial environments. Discusses reconstruction of the past ecological world at population, community and biogeographic levels. A well-illustrated and substantial volume giving accessible coverage of the full range of subjects within palaeoecology. Reviews and summarises all the major mass extinctions.
Author | : Mark Webster |
Publisher | : |
Total Pages | : 1126 |
Release | : 2003 |
Genre | : Evolutionary paleobiology |
ISBN | : |
Download Ontogeny and Phylogeny of Early Cambrian Olenelloid Trilobites, with Emphasis on the Late Dyeran Biceratopsidae Book in PDF, ePub and Kindle
Author | : Jonathan M. Adrain |
Publisher | : Springer Science & Business Media |
Total Pages | : 420 |
Release | : 2012-12-06 |
Genre | : Science |
ISBN | : 1461505712 |
Download Fossils, Phylogeny, and Form Book in PDF, ePub and Kindle
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 | : Thomas Arthur Hegna |
Publisher | : |
Total Pages | : 472 |
Release | : 2006 |
Genre | : Paleontology |
ISBN | : |
Download Systematics of Late Cambrian (Sunwaptian) Trilobites from the St. Charles Formation, Southeastern Idaho Book in PDF, ePub and Kindle
Previously unreported silicified trilobite faunas occur in a narrow stratigraphic interval of the Upper Cambrian (Sunwaptan) St. Charles Formation in the Bear River Range of southeastern Idaho. The faunas occur in four closely spaced rudstones and trilobite packstones indicating deposition in a shallow subtidal setting above storm wave base. At least 23 species are represented, included two undescribed genera and several undescribed species. The faunas are notable for their high trilobite abundance and pervasive silicification. Most coeval faunas have been described on the basis of small numbers of "crack-out" specimens, and the new material reveals many details of anatomy, including knowledge of most exoskeletal sclerites. The four trilobite-yielding beds contain markedly different taxon-abundance profiles, yet most species are shared between them. This suggests multiple, taphonomically-controlled samples of a similar underlying distribution, though true ecological variation cannot be discounted.
Author | : Smithsonian Institution |
Publisher | : |
Total Pages | : 326 |
Release | : 1969 |
Genre | : Paleobiology |
ISBN | : |
Download Smithsonian Contributions to Paleobiology Book in PDF, ePub and Kindle
Author | : Warren D. Allmon |
Publisher | : University of Chicago Press |
Total Pages | : 434 |
Release | : 2016-10-05 |
Genre | : Science |
ISBN | : 022637758X |
Download Species and Speciation in the Fossil Record Book in PDF, ePub and Kindle
Although the species is one of the fundamental units of biological classification, there is remarkably little consensus among biologists about what defines a species, even within distinct sub-disciplines. The literature of paleobiology, in particular, is littered with qualifiers and cautions about applying the term to the fossil record or equating such species with those recognized among living organisms. In Species and Speciation in the Fossil Record, experts in the field examine how they conceive of species of fossil animals and consider the implications these different approaches have for thinking about species in the context of macroevolution. After outlining views of the Modern Synthesis of evolutionary disciplines and detailing the development within paleobiology of quantitative methods for documenting and analyzing variation within fossil assemblages, contributors explore the challenges of recognizing and defining species from fossil specimens—and offer potential solutions. Addressing both the tempo and mode of speciation over time, they show how with careful interpretation and a clear species concept, fossil species may be sufficiently robust for meaningful paleobiological analyses. Indeed, they demonstrate that the species concept, if more refined, could unearth a wealth of information about the interplay between species origins and extinctions, between local and global climate change, and greatly deepen our understanding of the evolution of life.
Author | : Mark Webster |
Publisher | : |
Total Pages | : 528 |
Release | : 1999 |
Genre | : Geology, Stratigraphic |
ISBN | : |
Download Paleobiologic Aspects of Olenelloid Trilobites from the Uppermost Dyeran C-shale Member of the Pioche Formation, Nevada Book in PDF, ePub and Kindle
Author | : |
Publisher | : |
Total Pages | : 784 |
Release | : 2003 |
Genre | : Paleontology |
ISBN | : |
Download Bulletins of American Paleontology Book in PDF, ePub and Kindle