The sole Cuban representative of the bat genus Natalus, described as a fossil in 1919, was rediscovered in 1992 as an extant colony in a cave in the western tip of the island. Other extant Greater Antillean populations of this genus were known before from Jamaica and Hispaniola and, together with the fossil Natalus from Cuba, were considered synonyms of the continental species Natalus stramineus. Morphometric comparison of the living Cuban Natalus with other West Indian and mainland populations of the genus supports the taxonomic separation of the Greater Antillean populations of Natalus from Natalus stramineus. We hypothesize that Natalus major has a relatively high extinction potential due to its probable limited capacity for dispersal, and to its specialization in scarce hot-caves. We suggest that dependence on roosts of unreliable permanence probably introduces a high degree of stochasticity in the process of extinction of obligate cave-dwelling bats.