Species boundaries, biogeography, and intra-archipelago genetic variation within the Emoia samoensis species group in the Vanuatu Archipelago and Oceania

• Main Author: Hamilton, Alison Madeline
• Format: Text
• Language: unknown
• Published: LSU Digital Commons 2008
• Subjects: radiation; genetic differentiation; geographic variation; speciation; morphological variation; lizard; Scinciade; oceanic island; introduced species; phylogeography; Pacific; Young Island
• Online Access: https://digitalcommons.lsu.edu/gradschool_dissertations/3940; https://doi.org/10.31390/gradschool_dissertations.3940; https://digitalcommons.lsu.edu/context/gradschool_dissertations/article/4939/viewcontent/uc.pdf

Speciation, geographic variation, and genetic differentiation are fundamental processes that generate diversity, and understanding these processes are major goals of evolutionary biology. Evolutionary phenomena may be more observable on islands as compared to continental landmasses as a result of small population sizes, unoccupied niches, and the relative simplicity of island systems and their populations: physical isolation, shorter (and often well documented) geologic time scale, reduced faunal diversity, and lack of outside faunal influence. Yet, despite their incredible diversity, Pacific island faunas have received little research attention relative to other tropical regions. Using molecular data from several species of scincid lizards in the genus Emoia, I test hypotheses related to the generation and maintenance of biodiversity in Pacific oceanic systems, examining historical patterns of colonization, dispersal, and differentiation for a member of a vertebrate family with a broad distribution in the islands of the Pacific. This research is primarily conducted within the Vanuatu Archipelago, an ideal island group in which to examine questions associated with the role of island systems in promoting diversification and speciation. Vanuatu is an oceanic archipelago and its fauna is derived either via over water dispersal or cladogenesis. As it is also a geologically young island group (most islands emergent < 2 mya) interpretation and analysis of intra-archipelago variation during the early stages of a radiation are possible from data collected in this system. Comparison of patterns of diversification and differentiation recovered from Emoia in Vanuatu with patterns recovered for species in other well-studied, older island radiations (such as the Hawaiian Islands) enables an understanding of the generality of factors promoting diversity and speciation in island systems.