INTEGRATIVE EVOLUTIONARY BIOGEOGRAPHY OF THE NOSE-HORNED VIPER (VIPERIDAE: SQUAMATA) IN THE CYCLADIC ARCHIPELAGO AND CONTINENTAL GREECE
Roussos, Sa A
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The main goal of this dissertation was to use an integrative approach to understanding the morphology, evolutionary relationships and phylogeography of the nose-horned viper (Vipera ammodytes) in Greece with a focus on the isolated populations in the Cycladic archipelago. The dissertation comprises three data chapters: 1) morphological analysis of the Cycladic V. ammodytes populations compared to mainland conspecifics across the Balkans, and using mitochondrial DNA analyses; 2) to distinguish the evolutionary relationships, phylogeography and genetic diversity among the Cycladic V. ammodytes populations; and 3) the phylogenetics, phylogeography and systematics of V. ammodytes across all of Greece including the Cyclades, Peloponnese and the Ionian archipelago. Using a data set of morphological characters from over 900 specimens from across the species distribution in the Balkans, I used multivariate statistics to compare the morphology between the populations from the Cyclades and the three mainland subspecies for the first time ever. The results reveal that the Cycladic population’s exhibit dwarfism and significant differentiation from the other groups, overall being the most unique morphotype, suggesting the current taxonomic classification within V. a. meridionalis is invalid. Mitochondrial DNA analysis of 2,470 bp from four genes (16S rRNA, Control Region and Cytochrome b) from 150 samples revealed evolutionary relationships between island and mainland populations. Using Maximum Likelihood and Bayesian Inference methods I generated phylogenetic trees that depicted the Cycladic populations as a monophyletic insular radiation of lineages. There are clearly two identifiable lineages (one comprising the northern cluster of islands and the other comprising the central-southern cluster) which seem to have diverged from each other when the Mediterranean refilled after the Messinian Salinity Crisis. Island endemic lineages were also identified across the archipelago that diverged from each other throughout the Plio-Pleistocene glaciations. Using the same phylogenetic techniques above, I combined sequences made available for me from previous phylogenetic work of the species from the Balkans as well as many newly collected samples from Greece in this study. Ou results suggest that the Pindos Mountain rifting during the Miocene played a significant role in isolating populations from east to west on mainland Greece, and additionally island populations in the Ionian are divergent from their mainland conspecifics about the time the Mediterranean refilled. Distrubution limits of the clades and sub-clades are identified that were previously vague. The results are currently being used in reassessing the taxonomy of these geographical groups as monophyly, genetic distances and times of separation warrant these clades species-level taxonomic status when all populations from central-southern Greece were previously considered of the same subspecies V. ammodytes meridionalis.