Abstract

The Apogonidae is one of the most speciose coral reef fish families. Members of this family are found on every coral reef in all tropical and subtropical waters worldwide and yet, despite this apparent ubiquity, the systematic relationships of its species are poorly understood. Few studies have attempted to address the question of the family's evolutionary history and, as a result, little is known about the evolution of this major group of coral reef fish. This dissertation addresses this shortcoming by using characters derived from the skeleton, external morphology, and cephalic lateralis system to produce a cladistically derived hypothesis of the evolutionary relationships among the genera and subgenera of the family Apogonidae. The cephalic lateralis of the type species of each apogonid genus and subgenus was described and illustrated, and comments were made on the variability of this system within the supra-specific taxon to which the species belongs. The cephalic lateralis of apogonids is a highly diverse system; much variation exists within and among the family's genera and subgenera. Cladistic analyses resulted in a number of well-resolved, but not well-supported (as indicated by the consistency and retention indices), equally parsimonious cladograms. Homoplasies aside, all of the cladograms suggest that the apogonid genera Apogon sensu lato and Pterapogon sensu lato are not monophyletic as they are currently defined. The results of this research highlight the need for revision of the family's classification in order more accurately reflect the group's phylogenetic history.