Doctor of Philosophy, The Ohio State University, 2016, Evolution, Ecology and Organismal Biology

The Neotropics is the most species-rich region in the world. The current diversity and distribution of lineages present in this region is in part the result of complex ecological and evolutionary trends determined by environmental variables that have operated at diverse spatial and temporal scales. In addition, demographic processes have also influenced the structure of present-day phylogeographic patterns. Several studies have used Neotropical pitvipers as model organisms to explore historical diversification patterns and ecological processes that produce diversity in this region. However, few of those studies have explored patterns of diversification for groups of pitvipers likely influenced by one of the most salient features of the South American continent: The Andes. Here, I use a combination of molecular, morphological, and geographical data to explore diversification patterns and the evolutionary mechanisms implicated in the divergence of two distinct members of the genus Bothrops. First, I examine cryptic diversity present in the widespread and medically important snakes of the B. asper species complex (Chapter 2). Using a genomic and morphological dataset collected across the distribution of the group, I identified extensive phylogeographic structure, suggesting the influence of geographic barriers and/or differences in ecological niches in the recent diversification in the group. A deep divergence between a Central and South American clade is evident, but more recently diverged groups in South America show complicated patterns suggestive of recent divergence and/or gene flow among lineages. Next, I use this information to perform model-based analyses to investigate the demographic processes involved in the recent origin of two Ecuadorian montane lineages of these pitvipers (Chapter 3). This approach allowed me to resolve some of the discrepancies of evolutionary relationships found in Chapter 2. I found evidence for the isolation of one of the montane line (open full item for complete abstract)

Committee: H. Lisle Gibbs (Advisor); Paul A. Fuerst (Committee Member); Thomas Hetherington (Committee Member); John Freudenstein (Committee Member) Subjects: Ecology; Evolution and Development; Zoology