Ashe, James S.Chatzimanolis, Stylianos2018-03-052018-03-052003-04-291094-0782https://hdl.handle.net/1808/26069The staphylinid genus Elmas Blackwelder 1952 (type.species: Selma modesta Sharp 1876 from Chontales, Nicaragua) is revised for the first time. The two previously described species, E. modesta (Sharp) from Nicaragua and E. strigella (Bernhauer) from Brazil, are redescribed. Fifteen species are described as new: Elmas brooksi from Ecuador; Elmas costaricensis from Costa Rica; Elmas elassos from Ecuador; Elmas esmeraldas from Ecuador; Elmas falini from Suriname; Elmas gigas from Peru; Elmas guianas from-French Guiana; Elmas hanleyi from Costa Rica; Elmas hibbsi from Ecuador; Elmas lambas from Brazil; Elmas lescheni from Peru; Elmas panamaensis from Panama; Elmas patillas from Costa Rica; Elmas spinosus from Bolivia; and Elmas windsori from Panama. A key and illustrations of structural features and aedeagi are provided for identification of the known species. The phylogenetic relationships of the species of Elmas species are only weakly resolved by the available dataset. Elmas is strongly supported to be a monophyletic lineage, and E. strigella is the most basal species followed by E. lambos and E. guianas respectively. E. spinosus + E. falini + E. gigas are strongly supported to be a monophyletic . group; E. hfbbsi is weakly supported to be the sister group to these three species. The lineage (E. windsori · + E. costaricensis) + (E. panamaensis + E. patillas) is weakly supported in all trees. The lineage E. elassos + E. hanleyi + E. esmeraldas is also weakly supported, and the successive approximation analysis hypothesizes that E. modesta is also a member of this lineage.This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.http://creativecommons.org/licenses/by-nc-sa/4.0/StaphylinidaeStaphylininaeXanthopyginaElmasrevisionkeynew speciesphylogenyArticlehttps://orcid.org/0000-0001-9008-0611openAccess