The proposed study will derive an evolutionary tree for the rails (Aves, Rallidae), a large, ecologically diverse, and globally distributed family of typically "chicken-like" birds. Of this family, at least 58 species (including extinct species), roughly one-third of its members, are (were) flight-impaired or flightless. Within the historical frame work of the phylogenetic tree, an existing body of mensural data for the flightless species and their flighted relatives, and dissections of pectoral musculature in selected species-pairs, will be used to determine the anatomical changes associated with the repeated evolution of flightlessness in the group. Anatomical study will include microscopic examination of developmental mechanisms that produced the instances of flightlessness will also be determined, with particular attention being given possible evolutionary changes in the timing of developmental events (heterochrony). Finally, the geographical and ecological trends in flightless rails will be summarized, particularly possible changes in feeding behavior, habitat, and parameters of reproduction, patterns of extinction, and the ecological and genetic importance of insularity.
