Patterns of evolution in gobies (Teleostei: Gobiidae): a multi-scale phylogenetic investigation

dc.contributorFrank L Pezold
dc.creatorTornabene, Luke M.
dc.date2015-04-17T21:27:49Z
dc.date2015-04-17T21:27:49Z
dc.date2014-12
dc.descriptionA dissertation submitted in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY in MARINE BIOLOGY from Texas A&M University-Corpus Christi in Corpus Christi, Texas.
dc.descriptionThe family of fishes commonly known as gobies (Teleostei: Gobiidae) is one of the most diverse lineages of vertebrates in the world. With more than 1700 species of gobies spread among more than 200 genera, gobies are the most species-rich family of marine fishes. Gobies can be found in nearly every aquatic habitat on earth, and are often the most diverse and numerically abundant fishes in tropical and subtropical habitats, especially coral reefs. Their remarkable taxonomic, morphological and ecological diversity make them an ideal model group for studying the processes driving taxonomic and phenotypic diversification in aquatic vertebrates. Unfortunately the phylogenetic relationships of many groups of gobies are poorly resolved, obscuring our understanding of the evolution of their ecological diversity. This dissertation is a multi-scale phylogenetic study that aims to clarify phylogenetic relationships across the Gobiidae and demonstrate the utility of this family for studies of macroevolution and speciation at multiple evolutionary timescales. In the first chapter, I present a DNA sequence matrix derived from two nuclear genes to help resolve intergeneric level phylogenetic relationships with the Gobiidae. My study is the first to use data from conserved nuclear loci to infer relationships across the Gobioidei, and the results provide strong support for the monophyly of, and interrelationships between, several ecologically divergent clades. Specifically, I show that gobies are asymmetrically divided into two clades, one of which contains primarily marine species and the other comprises mostly estuarine or freshwater taxa. In the second chapter, I focus on the evolution of microhabitat association and morphology in one of the most diverse lineages of gobies, the reef-associated genus Eviota. Eviota species have invaded novel microhabitats multiple times throughout their evolutionary history, often occurring independently of diagnostic morphological changes in pectoral-fin ray branching and arrangement of sensory cephalic lateralis pores. The combination of historical ecological flexibility coupled with resilience to local extinction events may explain the elevated extant biodiversity in Eviota. Lastly, in my third chapter, I use Eviota as a model for studying fine-scale speciation in the Coral Triangle, a marine biodiversity hotspot in the Western Pacific Ocean. A phylogeographic analysis of two species complexes that have diverged within the Coral Triangle provides strong support for the hypothesis that the Coral Triangle serves as a `center of origin' or cradle of new species. Specifically, I demonstrate that a combination of biotic and abiotic factors may be contributing to rapid speciation both in allopatry and sympatry within the last 1.5 million years. The presence of recently diverged cryptic species in the Coral Triangle implies that our current estimates of biodiversity in this marine hotspot are severely underestimated. Ultimately, this dissertation demonstrates that gobies and other ecologically diverse clades of fishes serve as excellent model groups for studying the processes driving taxonomic and phenotypic diversification in marine species at a variety of spatial and temporal scales. This project will serve as a foundation for future studies that aim to use more comprehensive genomic datasets to address questions regarding drivers of speciation and ecological diversification in gobiid fishes.
dc.descriptionLife Sciences
dc.descriptionCollege of Science and Engineering
dc.identifierhttp://hdl.handle.net/1969.6/600
dc.languageen_US
dc.rightsThis material is made available for use in research, teaching, and private study, pursuant to U.S. Copyright law. The user assumes full responsibility for any use of the materials, including but not limited to, infringement of copyright and publication rights of reproduced materials. Any materials used should be fully credited with its source. All rights are reserved and retained regardless of current or future development or laws that may apply to fair use standards. Permission for publication of this material, in part or in full, must be secured with the author and/or publisher.
dc.subjectEcology
dc.subjectevolution
dc.subjectfish
dc.subjectphylogenetics
dc.subjectphylogeny
dc.subjectsystematics
dc.titlePatterns of evolution in gobies (Teleostei: Gobiidae): a multi-scale phylogenetic investigation
dc.typeText
dc.typeDissertation

Files