9806905 KARL The largest and most diverse order of vertebrates is the "ruling perches", or perciform fishes. Fishes of the perciform suborder Labroidei comprise about 15% of all living fish and include the eastern Pacific surfperches, reef dwelling damselfishes, parrotfishes, wrasses, and the well-known cichlids. Previously, this wide array of species has been placed together in the Labroidei because these fish have modified structures in the throat region (a "modified pharyngeal apparatus") used to crush or otherwise prepare food items (prey) for digestion. The sheer diversity of this assemblage has hindered the construction of a classification that accurately reflects the history (phylogeny) of these fish, so it is unclear whether the pharyngeal apparatus characters signal the presence of one or many lineages. In this research, Stephen Karl will use DNA sequence data from three separate genes to reconstruct the phylogenetic relationships of labroid fishes, beginning the process of putting the classification of these fishes on a sound basis, and determining whether morphological features such as those associated with the pharyngeal apparatus appeared in one exceptionally diverse lineage of fishes or, rather, has appeared separately in several different, and hence only superficially similar, groups. The work should provide a firm foundation for ongoing and future comparative studies of the physiology and behavior of these numerous, and frequently economically important, fishes.
