Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 92 for “"cryptic species"”.
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Evolutionary Genetics of Dictyostelids: Cryptic Species, Sociality and Sex
Dictyostelium discoideum serves as an ideal system to study social evolution because of the social stage of its lifecycle, where individuals aggregate to build a multicellular structure. However, much of its basic biology remains unknown and this limits its utility. I used three separate projects …
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DNA Barcode Examination of North American Mayflies Across Their Natural Distribution Reveals Cryptic Species Complexes
… and compared across the entire range of a given species. Rather, most studies employing DNA barcoding focus on relatively few individuals and even fewer sites. Together, this may underestimate intraspecific variance, confounding efforts to distinguish between intraspecific and interspecific …
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Resolving a Cryptic Species Complex: Application and Utility of Mitochondrial 16S and Nuclear Its1 Molecular Markers in Pyrgulopsis Micrococcus
… micrococcus (Hydrobiidae: Nymphophilinae) is a cryptic species complex found among three river drainages in the Death Valley system. Jennings (2001) used mitochondrial cytochrome c oxidase subunit I (mtCOI) DNA sequences to examine intra-and inter- population genetic variation in 13 populations …
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Parvulastra exigua in South Africa: one species or more?
… recent studies have suggested that there is a cryptic species of P. exigua in South Africa, based on genetic evidence or the differential placement of the gonopores. A morphological, anatomical and genetic investigation was performed on a total collection of 346 P. exigua and 8 P. dyscrita …
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Molecular and morphological factors contributing to the resolution of the taxonomy of Octopus vulgaris Type III
Cryptic species are common in the marine environment, particularly among invertebrates. The genus Octopus Cuiver, 1797 is considered a ‘catch all' genus due to the lack of morphological traits available to distinguish closely-related species. In recent years, the Octopus vulgaris species complex …
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The evolution of freeze tolerance in a historically tropical snail
Geographic range differences among species may result from differences in their physiological tolerances. In the intertidal zone, marine and terrestrial environments intersect to create a unique habitat, across which physiological tolerance strongly influences range. The snail Melampus bidentatus …
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Life cycle evolution and systematics of Campanulariid hydrozoans
… integra and elytia gracilis may represent cryptic species, while Obelia longissima may be cosmopolitan. Chapter 4 investigates Obelia geniculata phylogeography. Japanese and North Atlantic 16S rDNA and COI sequences are calibrated against the opening of the Bering Strait. Substitution rates …
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Life cycle evolution and systematics of Campanulariid hydrozoans
… integra and Clytia gracilis may represent cryptic species, while Obelia longissima may be cosmopolitan. Chapter 4 investigates Obelia geniculata phylogeography. Japanese and North Atlantic 16S rDNA and COI sequences are calibrated against the opening of the Bering Strait. Substitution rates …
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Interrelationships Among Monorchiid Trematodes with Special Emphasis on Some Northwestern Atlantic Genera
… family of flukes (Trematoda: Digenea) comprising species that parasitize the digestive tract of estuarine and marine fishes as adults. Compared with other oceans, recent morphological or molecular taxonomic work conducted on monorchiid species from the northwestern Atlantic Ocean has been sparse …
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Phylogeograpy of Aphanicercella cassida (Plecoptera : Notonemourida) : cryptic speciation?
… very limited habitat in which to survive. The species of stonefly studied in this project (Aphanicercella cassida) has a very wide distribution unlike most other species which have a limited range. Of particular interest is a population in Mpumalanga (north of South Africa) which is very …
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Population genetics of the endemic red-chested sea cucumber, Hemiocnus insolens, along the southern coastline of Africa
… and white) prompting the existence of possible cryptic species. The aim of the study is to sequence the genomic markers of each colour variation using Sanger sequencing and metagenomic sequencing to analyse their phylogenetic and associated community structure to delimit whether the colour …
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Genetic, Morphological, and Behavioral Analysis of the Oklahoma Salamander (Eurycea Tynerensis) in Southwestern Missouri
… two sympatric color morphs for the presence of a cryptic species. I also obtained sequence data from the mitochondrial cytochrome-b gene of 21 salamanders, representing 4 populations. Sympatric color morphs did not differ significantly in morphometrics or in behavior. Sequencing data reveal that …
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Biochemical investigations of the evolution and systematics of certain pocket mice (Rodentia: Heteromyidae)
Several of the twenty or more species of pocket mice of the subfamily Perognathinae are questionable as to their systematic status and relationship to other species. In this study, three such species are examined. Perognathus amplus and P. longimembris are so similar in morphology and karyotype …
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Phylogeography and ecology of New Zealand freshwater Amphipoda (Paracalliope, Paraleptamphopus, and Phreatogammarus)
… behaviour can be used to delineate potential species boundaries and to assess the role of sexual selection. The endemic genus Phreatogammarus has been found in only a limited number of sites and is not very abundant. An analysis of the genetic variation of two species within the genus using …
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Reassessment of species limits and diversification process in the Cape grass genus Ehrharta Thunb
… islands” of the GCFR, potentially resulting in cryptic species. This work seeks to test the relative importance of ecological versus non-ecological processes in powering speciation at different elevations in the GCFR, and to assess the existence of multiple, range-restricted cryptic species at …
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The conservation genetics of a newly recognised Cape Peninsula endemic Rose's Mountain toad (Capensibufo rosei)
… the hardest by anthropogenic global change, many species remain poorly studied. Capensibufo rosei, Rose's Mountain Toad, is a restricted range species that survives in a few small, isolated montane populations in the extreme south-western Cape of South Africa. A recent study of the genus revealed …
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Developing a predictive geospatial habitat model for a rare species of salamander in Tennessee: a case study for the green salamander (Aneides aeneus)
… Cope and Packard 1881) are a secretive and cryptic species of salamander that can be relatively difficult to detect, due to their occupation of arboreal habitats. The incorporation of geospatial tools is critical in developing models that can be used to predict undocumented locations in …
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A contribution to species delimitation and taxonomy of North American Entomobrya (Collembola: Entomobryidae)
… of DNA sequence divergence among congeneric species suggest that circumscription of species based solely on traditional morphological and color pattern characters provide a very conservative estimate of actual species diversity. Many described species in the genera Orchesella, Isotomurus and …
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Identification and isolation of microsatellite loci from the Trematode Echinostoma Trivolvis for use in interspecific and intraspecific variation studies
… phylogenetic relationships and potential cryptic species. The echinostome population in central California, as a result of this project, may be much more diverse than has long been reported in the literature.</p>
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Assessment of mudpuppy (Necturus maculosus) presence along the St. Clair-Detroit River System using environmental DNA and occupancy modeling
<p>The mudpuppy (Necturus maculosus) is cryptic, fully aquatic salamander within the Great Lakes region. Once abundant throughout its range, evidence now suggests that there have been declines due to habitat loss and lampricide use. Information on the status of mudpuppies along the St. …
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