The virus family Filoviridae includes 2 genera, the Marburg viruses and the Ebola viruses. The ecology of the filoviruses is poorly known, and indeed their host relationships remain completely unknown. An earlier effort prioritized mammalian taxa as to their possible status as the long-term coevolved reservoir of the filoviruses based on a coarse, regional classification of occurrences; here, we greatly refine the geographic data set for the mammalian taxa based on rich occurrence data sets and range interpolations from ecological niche models for each species involved. This improved detail permits a much more detailed inspection of distributional overlap patterns, and consequently a shorter list of candidate taxa—geographic analysis of 124 mammalian clades led to identification of 55 groups of interest that coincide spatially with known filovirus outbreaks, and fulfill the requirements of several additional assumptions. We discuss implications of our results for the search for the filovirus reservoir, and for research in African mammalogy.