SUMMARY
Mammal diversity in Costa Rica is considerably high given the size of the country (51,100 km2), and has increased in recent years. Taxonomic changes together with distribution extension records have contributed to such an increase. Here we present the revised and updated list of mammals confirmed for Costa Rica based on previous lists and recent additions obtained from literature, with notes on endemism and conservation status. This updated list was based on Rodríguez-Herrera et al. (2014a) list, compared and matched with the most updated taxonomic review. A total of 256 mammals are now confirmed for Costa Rica, with the order Chiroptera and Rodentia as the most representative. We report 30 endemics for Costa Rica, including those species whose distribution is limited to the country and one of its two neighboring countries, from which 21 are rodents. Compilation on conservation status information reveals 29.6 % of species within the list classified as threatened, either by Costa Rican or international environmental authorities. Increase in new studies on mammals all around the world is leading to the discovery of new species. While systematic and phylogenetic revisions is revealing new taxonomic relationships, and cryptic species. Mainly on highly diverse and taxonomically challenging groups, as bats, rodents, and shrews, as we evidence here. Several threatened and endemic species occur in Costa Rica, where the greatest endemism area is the high elevations, and most endemic species are mice. The creation and establishment of protected areas in a large part of the Costa Rican territory has favored the prevalence of a diverse mammalian assemblage.