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Engstrom, T. N. (2003). Molecular studies of phylogenetics, ecology and conservation of softshell turtles (family trionychidae) and amazon river turtles (podocnemis unifilis). Unpublished thesis , University of California, Davis. 
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Resource type: Thesis/Dissertation
BibTeX citation key: Engstrom2003
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Keywords: Chitra, Chitra chitra, Chitra vandijki, Genetik = genetics, Podocnemididae, Podocnemis, Podocnemis unifilis, Schildkröten = turtles + tortoises, Trionychidae
Creators: Engstrom
Publisher: University of California, Davis		 Views: 2/998
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Abstract     
The use of DNA sequence data is becoming ubiquitous in systematics, historical biogeography, conservation, and ecology. In this dissertation I use molecular data to address questions regarding phylogenetic relationships, historical biogeography, ecology, and conservation of turtles, spanning a broad temporal scale ranging from inference of phylogenetic relationships among lineages that diverged 100+ million years ago, to estimates of contemporary migration among populations. Softshell turtles are a morphologically unique, ancient, group of economically important turtles. They include the largest freshwater turtles in the world, and some of the most threatened vertebrate species. A strong phylogeny for the group is essential in assessing biodiversity, making management decisions, and understanding the evolution of their bizarre morphologies. My analyses of previously published morphological data with DNA sequence data from two mitochondrial genes converge on a set of well-supported relationships among all recognized species of extant softshell turtles (Family Trionychidae). I use this phylogeny for two purposes (1) as the basis for a novel rank-free classification; and (2) to retrospectively examine strategies for analyzing saturated mtDNA data in deep phylogeneties where increased taxon sampling is not an option. The two parts of Chapter 2 address the conservation implications of phylogeneties in the widespread Southeast Asian softshell turtle genus Chitra. My mtDNA phylogeny shows three widely divergent lineages within what was formerly considered a single widespread endangered species. Confirmation of the validity of the Chitra chitra from Thailand, Malaysia and Sumatra Java and the description of Chitra vandijki from Myanmar is the first step towards effective management of these two critically endangered species. The final study extends on the use of mtDNA sequence data from inference of phylogenetic relationships to estimating rates of contemporary migration among protected populations of the yellow-spotted Amazon river turtle, Podocnemis unifilis, in the Pacaya Samiria National Reserve in Perú. This study shows that there may be extensive migration among populations in different river drainages within the reserve. This is in contrast with high levels of population subdivision seen in this species in other regions of Amazonia and may reflect differences in the biogeographic history of the regions.
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