We studied molecular and morphological variation in small fruit-eating bats (Artibeus) in northern South America to establish species boundaries, evolutionary relationships, and distributional limits. Although this is a speciose genus with some of the most common bats in Neotropical forests, resolution of taxonomy and their identification has been difficult. Our molecular phylogeny based on Bayesian and parsimony analyses of cytochrome b variation includes a well supported topology of A. glaucus glaucus sister to a clade of A. gnomus and A. glaucus bogotensis indicating that A. glaucus is a paraphyletic amalgam. A re-assessment of morphology corroborates differences between A. g. bogotensis from the Andean valleys of Colombia east into the Guianas and A. g. glaucus from western Amazonia. Thus, we recognize A. bogotensis and A. glaucus as distinct and allopatrically occurring species. Based on a Kimura-2 parameter model of substitution for cytochrome b, there was 1.2% sequence divergence within A. bogotensis, and 9.5% sequence divergence between A. bogotensis and A. glaucus. Compared to A. glaucus, A. bogotensis has prominent white facial stripes, a less hirsute interfemoral membrane, less robust orbitorostral region, and also lacks a small third lower molar. Within the Guiana region, there are three species with overlapping distributions (A. bogotensis, A. cinereus, and A. gnomus), however, they are sympatric only within the interior lowland forest near savannas. All other habitats including coastal forest, lowland forest, savanna, and highland forest have only two sympatric species, one of which is relatively more abundant (> 70%).