Keywords

Phylogenetics, phylogeography, atlantic salt marsh snake, southern water snake, subspecies, evolutionary history

Abstract

Biogeography provides a window into the evolutionary history of populations, and helps explain the diversity and distribution of life through time. Viewed from a systematic perspective, biogeographic studies generate convincing arguments to explain the relationships among organisms and categorize them into useful taxonomies. When taxonomies do not reflect evolutionary histories, inaccurate representations of biodiversity confound future studies and conservation efforts. Two thamnophiine snakes, Nerodia clarkii and Nerodia fasciata, harbor unique morphological and ecological adaptations that obscured natural groupings, leading to controversial taxonomic delimitations. Additionally, population declines documented in N. clarkii compressicauda and N. clarkii taeniata led managers to list N. clarkii taeniata as threatened in 1977. I generated a baseline for continued biogeographic and systematic study of the Nerodia clarkii/fasciata clade. I used mitochondrial DNA to build a parsimony-based haplotype network, infer the phylogenetic relationships between the two species and their thamnophiine relatives, and estimate the divergence times of major N. clarkii/fasciata clades. With these data, I tested biogeographic and systematic hypotheses about the origin and distribution of diversity in this clade. I used principal components analyses to summarize morphological data and discuss ecological observations in search of characters that may unite genetic or taxonomic units. The analyses revealed a peninsular and a panhandle clade in Florida that appeared to iv diverge as a result of Pleistocene glacial fluctuations. I found no support genetically, morphologically, or ecologically for the current taxonomy, indicating a need for range-wide research to generate revised nomenclature. My results do not support the protection status of N. clarkii taeniata

Notes

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Graduation Date

2013

Semester

Spring

Advisor

Parkinson, Christopher

Degree

Master of Science (M.S.)

College

College of Sciences

Department

Biology

Degree Program

Biology

Format

application/pdf

Identifier

CFE0004760

URL

http://purl.fcla.edu/fcla/etd/CFE0004760

Language

English

Release Date

May 2014

Length of Campus-only Access

1 year

Access Status

Masters Thesis (Open Access)

Subjects

Dissertations, Academic -- Sciences, Sciences -- Dissertations, Academic,

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Biology Commons

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