• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 22
  • 11
  • 3
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 40
  • 12
  • 8
  • 7
  • 7
  • 6
  • 6
  • 6
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 4
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Paleobiogeography of Devonian bryozoa in Laurussia

Holmquist, Emily Kristin. January 2008 (has links)
Thesis (M.S.)--Michigan State University. Dept. of Geological Sciences, 2008. / "Advisor, Dr. Robert L. Anstey"--Acknowledgements. "The purpose of this study is to delineate patterns of endemism in Devonian bryozoans in North America and Europe, and to suggest hypotheses for the development of biogeographic regions during the period"--Introd. Title from PDF t.p. (viewed on Aug. 4, 2009) Includes bibliographical references (p. 38-44). Also issued in print.
2

Eurasian Middle and Late Miocene Hominoid Paleobiogeography and the Geographic Origins of the Homininae

Nargolwalla, Mariam C. 25 September 2009 (has links)
The origin and diversification of great apes and humans is among the most researched and debated series of events in the evolutionary history of the Primates. A fundamental part of understanding these events involves reconstructing paleoenvironmental and paleogeographic patterns in the Eurasian Miocene; a time period and geographic expanse rich in evidence of lineage origins and dispersals of numerous mammalian lineages, including apes. Traditionally, the geographic origin of the African ape and human lineage is considered to have occurred in Africa, however, an alternative hypothesis favouring a Eurasian origin has been proposed. This hypothesis suggests that that after an initial dispersal from Africa to Eurasia at ~17Ma and subsequent radiation from Spain to China, fossil apes disperse back to Africa at least once and found the African ape and human lineage in the late Miocene. The purpose of this study is to test the Eurasian origin hypothesis through the analysis of spatial and temporal patterns of distribution, in situ evolution, interprovincial and intercontinental dispersals of Eurasian terrestrial mammals in response to environmental factors. Using the NOW and Paleobiology databases, together with data collected through survey and excavation of middle and late Miocene vertebrate localities in Hungary and Romania, taphonomic bias and sampling completeness of Eurasian faunas are assessed. Previous bioprovincial zonations of Europe and Western Asia are evaluated and modified based on statistical analysis of Eurasian faunas and consideration of geophysical, climatic and eustatic events. Within these bioprovinces, occurrences of in situ evolution and directionality of dispersals of land mammals are used as a framework to address and evaluate these same processes in Eurasian apes. The results of this analysis support previous hypotheses regarding first occurrences and phyletic relations among Eurasian apes and propose new ideas regarding the relations of these taxa to previously known and newly discovered late Miocene African apes. Together with analysis of environmental data, Eurasian mammals support the hypothesis that the descendant of a Eurasian ape dispersed to Africa in the early late Miocene (top of MN7/8 or base of MN9), however the question of whether this taxon founded the African ape and human lineage remains equivocal.
3

Eurasian Middle and Late Miocene Hominoid Paleobiogeography and the Geographic Origins of the Homininae

Nargolwalla, Mariam C. 25 September 2009 (has links)
The origin and diversification of great apes and humans is among the most researched and debated series of events in the evolutionary history of the Primates. A fundamental part of understanding these events involves reconstructing paleoenvironmental and paleogeographic patterns in the Eurasian Miocene; a time period and geographic expanse rich in evidence of lineage origins and dispersals of numerous mammalian lineages, including apes. Traditionally, the geographic origin of the African ape and human lineage is considered to have occurred in Africa, however, an alternative hypothesis favouring a Eurasian origin has been proposed. This hypothesis suggests that that after an initial dispersal from Africa to Eurasia at ~17Ma and subsequent radiation from Spain to China, fossil apes disperse back to Africa at least once and found the African ape and human lineage in the late Miocene. The purpose of this study is to test the Eurasian origin hypothesis through the analysis of spatial and temporal patterns of distribution, in situ evolution, interprovincial and intercontinental dispersals of Eurasian terrestrial mammals in response to environmental factors. Using the NOW and Paleobiology databases, together with data collected through survey and excavation of middle and late Miocene vertebrate localities in Hungary and Romania, taphonomic bias and sampling completeness of Eurasian faunas are assessed. Previous bioprovincial zonations of Europe and Western Asia are evaluated and modified based on statistical analysis of Eurasian faunas and consideration of geophysical, climatic and eustatic events. Within these bioprovinces, occurrences of in situ evolution and directionality of dispersals of land mammals are used as a framework to address and evaluate these same processes in Eurasian apes. The results of this analysis support previous hypotheses regarding first occurrences and phyletic relations among Eurasian apes and propose new ideas regarding the relations of these taxa to previously known and newly discovered late Miocene African apes. Together with analysis of environmental data, Eurasian mammals support the hypothesis that the descendant of a Eurasian ape dispersed to Africa in the early late Miocene (top of MN7/8 or base of MN9), however the question of whether this taxon founded the African ape and human lineage remains equivocal.
4

Quantitative paleobiogeography of Maysvillian (Late Ordovician) brachiopod species of the Cincinnati Arch a test of niche modeling methods for paleobiogeographic reconstruction /

Walls, Bradley J. January 2009 (has links)
Thesis (M.S.)--Ohio University, June, 2009. / Title from PDF t.p. Includes bibliographical references.
5

Descriptive and Comparative Morphology of African Titanosaurian Sauropods: New Information on the Evolution of Cretaceous African Continental Faunas

Gorscak, Eric January 2016 (has links)
No description available.
6

The South African Mesozoic: advances in our understanding of the evolution, palaeobiogeography, and palaeoecology of sauropodomorph dinosaurs

McPhee, Blair Wayne January 2016 (has links)
A dissertation submitted to the Faculty of Science, University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, 2016. / The Palaeontological record of South Africa is remarkable in that it preserves the two major temporal transitions of the Mesozoic: The Triassic–Jurassic boundary (the Elliot Formation) and the earliest depositional stages of the Cretaceous (the Kirkwood Formation). Work within the Elliot Formation has reiterated the importance of this horizon for our understanding of the early evolution and subsequent radiation/diversification of basal sauropodomorph dinosaurs. Moreover, inextricably contained within this radiation is the early evolution of the columnar-limbed, long necked sauropods, the largest terrestrial animals to have ever evolved. The Elliot Formation therefore imparts vital information on the genesis of the group that would become the dominant dinosaurian herbivores throughout most of the Mesozoic. However, several outstanding issues obscure a full understanding of this important radiation. Of primary concern is the complicated taxonomy of the sauropodomorphs of the Upper Triassic lower Elliot Formation and a lack of current consensus as to what precisely constitutes a true sauropod. The latter issue is further complicated by a lack of well-preserved sauropod material prior to the Toarcian. The discovery of new, associated material from both the lower and upper Elliot Formation has direct relevance to both of these concerns. Specifically, although the genus Eucnemesaurus is supported in the current analysis, the bauplan diversity of lower Elliot Sauropodomorpha remains relatively conservative save for the stocky pedal architecture of Blikanasaurus and the autapomorphically robust morphology of a newly rediscovered ilium that is potentially referable to it. Within the upper Elliot Formation, a recently discovered highly apomorphic bone-bed is diagnosed as a new species of sauropod that, in addition to placing the earliest unequivocal sauropods within the basal rocks of the Jurassic, suggests the underlying ecological factors driving the divergence of the derived sauropodan bauplan. In addition to new information provided by the Elliot Formation, two decades’ worth of collecting from the Early Cretaceous Kirkwood Formation affords a long overdue insight into the sauropod fauna occupying southern Gondwana at the outset of the Cretaceous. The surprising diversity of forms recognized from the Kirkwood suggests that the taxonomic decline of Sauropoda previously inferred for the earliest Cretaceous is a product of sampling bias compounded by a generally poor fossil record. However, a lack of absolute dates for the Kirkwood Formation means that the plethora of “Jurassic-type” specimens is potentially explicable via their being contemporaneous with similar Late Jurassic faunas of eastern Africa and North America. / LG2017
7

Paleobiogeography of Miocene to Pliocene Equinae of North America a phylogenetic biogeographic and niche modeling approach /

Maguire, Kaitlin Clare. January 2008 (has links)
Thesis (M.S.)--Ohio University, June, 2008. / Title from PDF t.p. Includes bibliographical references.
8

The impact of the Richmondian Invasion on paleobiogeographic distribution of taxa in the Late Ordovician C₄ sequence (Richmondian Stage, Cincinnati, Ohio) including a comparison of range reconstruction methods

Dudei, Nicole L. January 2009 (has links)
Thesis (M.S.)--Ohio University, August, 2009. / Title from PDF t.p. Includes bibliographical references.
9

Quaternary biogeography of western North America insights from mtDNA phylogeography of endemic vertebrates from Haida Gwaii /

Byun, S. Ashley January 1998 (has links) (PDF)
Thesis (Ph. D.)--University of Victoria, 1998. / Includes bibliographical references (leaves 243-269).
10

Evolução e filogenia de Pleurodira (Testudines) com a descrição de uma nova espécie de Bairdemys (Podocnemidae) do Mioceno médio da Venezuela / Evolution and phylogeny of Pleurodira (Testudines) with the description of a new Bairdemys (Podocnemidae) species from the middle Miocene of Venezuela

Ferreira, Gabriel de Souza 29 January 2015 (has links)
Apesar de negligenciados por muito tempo, os Pleurodira, uma das duas linhagens de Testudines (cágados, jabutis e tartarugas-marinhas), vem atraindo crescente atenção dos pesquisadores, com trabalhos que geralmente tratam da descrição de novas espécies (viventes ou extintas), de comportamentos ou hábitos alimentares, ou de análises filogenéticas dos sub-grupos de Pleurodira, como Chelidae ou Pelomedusoides, esta sub-dividida em duas linhagens com representates viventes: Pelomedusidae e Podocnemidae. Análises filogenéticas com táxons terminais de todos os principais grupos de Pleurodira existem apenas com dados moleculares. Assim, uma análise baseada em dados morfológicos que englobe táxons de todos os grandes clados do grupo, incluindo fósseis, faz-se necessária para melhor compreensão da história evolutiva do grupo. Nesta dissertação, descrevemos uma nova espécie de Bairdemys (Podocnemidae) do Mioceno médio da Venezuela e a incluímos em uma análise filogenética com ampla amostragem taxonômica, incluindo táxons de todas as linhagens de Pleurodira. Esta análise é baseada em caracteres morfológicos (novos ou previamente propostos) e a maior análise filogenética exclusiva do grupo já realizada, permitindo inferências sobre padrões gerais de diversificação e morfologia de Pleurodira. Ao mesmo tempo, o novo táxon descrito apresenta características morfológicas que, juntamente com aspectos geológicos de sua localidade tipo, permitem a inferência de que houve, durante o Cenozóico, uma irradiação marinha de Podocnemidae, que alcançou grande sucesso, principalmente no final do Oligoceno e começo do Mioceno / Though neglected for a long time, one of the two lineages of Testudines (turtles and tortoises) the Pleurodira has been attracting the researchers, whose articles usually deal with descriptions of new species (extant and extinct), behavior or feeding habits, or phylogenetic analyzes of one of the subgroups of Pleurodira, Chelidae or Pelomedusoides, the latter subdivided in two lineages with extant taxa: Pelomedusidae and Podocnemidae. There some phylogenetic analyzes with terminal taxa from the main groups of Pleurodira, but only with molecular data. Therefore, a morphological data analysis containing taxa from all the clades of this group, including fossils, is necessary to better understand the evolutionary history of this lineage. In this dissertation, I describe a new species of Bairdemys (Podocnemidae) from the middle Miocene of Venezuela, and I include it in a phylogenetic analysis with extensive taxonomic sampling, including taxa from all the lineages of Pleurodira. This analysis is based on morphological characters (new and previously proposed ones) and it is the largest exclusive phylogenetic analysis ever made for Pleurodira, allowing inferences about the general patterns of diversification and morphology of the group. At the same time, the new described táxon shows morphological characters that, along with geological aspects of its type locality, allow inferences about a marine wave of diversification of Podocnemidae during the Cenozoic, which achieved great success, specially by the end of Oligocene and beginning of Miocene

Page generated in 0.0441 seconds