Area-relationships in the Neotropical lowlands: an hypothesis based on raw distributions of Passerine birds

Abstract. Using raw geographic distributions for Neotropical species and subspecies of the perching birds (Order Passeriformes), we present an hypothesis of area-relationships for twelve avian areas of endemism in the lowland Neotropics. With 1717 characters (distributions of species and subspecies) we find a single most parsimonious tree of area-relationships. This topology does not match area-relationships determined from phylogenetic studies of morphologic characters in some Neotropical birds. Analyses of data partitions representing major taxonomic subdivisions within Passerine birds provide many different hypotheses of area-relationships. These results suggest that a single set of Neotropical area-relationships is not likely. In the future, we suggest greater emphasis be placed on research to document patterns in the Neotropics, particularly phylogenetic patterns, than on speculation about what processes have been important for diversification.