The parrotfishes, strongly reef associated perciform fishes have a recent history of diversification. Although initial divergence of the parrot fishes commenced during the Oligocene diversification resulting in the present day assemblages occurred in the Pliocene and early Pleistocene. In this interval parrotfishes colonized the world's tropical reefs and today represent a numerically dominant assemblage of grazing fishes. Colonization occurred differentially resulting in distinctive taxonomic and functional assemblages in the tropical Atlantic vs the Indo-Pacific and in clearly partitioned faunas within the Indo-Pacific. Phylogenetic analysis retrieves two major clades of parrot fishes the Sparisomatinines with the greatest diversity in the Atlantic ocean and the scarinnines with limited representation in the Atlantic but the dominant group in the Tndo-Pacific. Demographic analysis reveals that members of the Atlantic sparisomatinines manifest faster growth rates and generally shorter life spans than the scarinines of the Indo-Pacific, suggesting that for this group the demographic clocks are running faster in the Atlantic. Resolution of this issue requires taking phylogenetic influences, ocean basin history and biogeographic and habitat configurations into account. Given the broad distribution of this group it is possible to evaluate a hypothesis of demographic differentiation in all the major clades on a biogeographic scale. To achieve this representatives of all major clades from the Atlantic, East Pacific and the entire Tndo-West Pacific will be analysed for demographic and life history trends taking into account phylogeny, ocean basin history and habitat configuration.