Dr. Schaefer studies the systematics, biogeography, and evolutionary morphology of tropical freshwater fishes of Africa and South America.  His research seeks to resolve problems in taxonomy, classification, and evolution in those fish groups that dominate the ecology of riverine systems, such as catfishes and characiforms.  Fieldwork involves discovery of undescribed fish diversity in poorly known regions, such as the Amazon and Orinoco Rivers of South America.  Current projects include systematics and biogeography of Andean freshwater fishes and taxonomic revision of the family Astroblepidae, a group of catfishes that live at high elevations in the Andes of South America.  He is also engaged in phylogenetic studies of the trichomycterid catfishes and revisions of African alestid characiform fishes.  Recent fieldwork in Peru, Ecuador, and Venezuela has surveyed the diversity of Andean fishes up to 4,500 m (14,760 ft.) elevation and resulted in the addition to the Museum of several new and important collections.