Evolution on coral reefs, with systematic treatments of the pencil and fairy wrasses (Teleostei: Labridae: Pseudojuloides & Cirrhilabrus)

Abstract

Fishes represent half of all of the living species of vertebrates that have been described to date. Most species of fish are marine, with at least a third found exclusively in coral reefs. Yet the phylogenetic relationships of coral reef fishes and the drivers of their diversification remain poorly understood, particularly for taxonomic groups at the incipient stages of speciation. Despite the increasing application of high-throughput sequencing techniques to other taxonomic groups, much of the research conducted on coral reef fishes still relies on more traditional sources of information, such as morphology and mitochondrial sequence data. These methods are unreliable in resolving taxonomically problematic groups such as the Labridae, where many groups are still rapidly radiating, and the processes driving this are not well understood. It is therefore prudent to use a combined, integrative approach using both morphological and high-throughput sequencing techniques. This thesis uses the aforementioned techniques, integrated with morphological studies, to tease apart the relationships for members of the Labridae, in particular the fairy and pencil wrasses (Cirrhilabrus and Pseudojuloides respectively). Additionally, it includes taxonomic descriptions of eight new species, as well as investigations into general themes on coral reefs, including, but not limited to hybridisation, deep reef communities, and historical biogeography.