Life in the shadows: The Gnamptogenys mordax group (Hymenoptera: Formicidae)

The Gnamptogenys mordax group is a poorly known clade of Neotropical ants with many hallmarks of a relict lineage. They mostly occur in mature wet forest habitats, always in small colonies, and they are always rare. None are known to be diurnal surface foragers and all appear to be predators. They occur in two ecomorphs: large nocturnal surface foragers with large eyes, and small species with small eyes, restricted to litter and rotten wood. The intensive sampling of ants in Central America and fieldwork throughout South America has permitted the accumulation of many specimens representing unknown species; clearly making the last revision obsolete. This work addresses the taxonomy and phylogeny of the group using a combination of morphological examination of all specimens and phylogenomic Ultra-Conserved Elements (UCEs) from 77 in-group specimens. The phylogeny supports morphological species delimitations and reveals a previously unknown radiation of species in wet forests of Central America. We increase the number of known species from 9 to 39, including 26 new species. The species are described and imaged. Their distribution ranges are mapped and natural history information, if available, is provided. Illustrated keys facilitate species identification. Many species have restricted ranges. This endemism, combined with low density and restriction to mature forest, suggests that most species may be threatened by habitat loss.