The New World species of the genus Leptogenys are revised based upon their external morphology. The genus is present from southern U.S.A. to northern Argentina, including the Caribbean and Galapagos Islands. Eighty-one species are recognized, 13 are synonymized, and 49 are described as new. The New World fauna can be divided into 12 informal species groups and 8 species considered incertae sedis. A phylogeny using morphology recovers L. linearis as sister to the rest of the New World taxa, besides existence of a basal polytomy and two large clades. Reproduction is mostly through ergatoid queens, with gamergate reproduction apparently only present in several taxa outside of the pusilla clade, while winged queens are present only in 3 species of the pusilla clade. The African tramp species L. maxillosa is also present. Most species dwell in humid forested areas, but there are several arid zone endemics. Most species are specialist predators of oniscomorph isopods. There is no evidence for army ant behavior in the New World species. The generic diagnosis and a key for the identification of the workers is included, as well as illustrations of all the known New World species.

Ants, taxonomy, identifi cation, neotropical, diversity