English common names are given to the rank of family or subfamily. For most mammals, particularly the speciose and secretive bats and small rodents, there are no standardized names as there are for birds. Distributional abbreviations used are AM for Amazonas State, BO for Bolívar State, DA for Delta Amacuro State, GU for Guyana, SU for Surinam, and FG for French Guiana. Caution should be exercised when interpreting biogeographic implications of this checklist. Although it is for the "Guiana Shield", the delineation is political and based on country or state boundaries. From this preliminary checklist, researchers are encouraged to investigate the regional differences and local composition of the mammalian fauna. For instance, some species more typical of western Amazonia than the Guiana Shield are found only in Amazonas State of Venezuela (Voss et al., 2001). Additional distributional and taxonomic comments are in square brackets after the species name.