Brachymyrmex species with tumuliform metathoracic spiracles: Description of three new species and discussion of dimorphism in the genus (Hymenoptera, formicidae)

Abstract

Brachymyrmex is a taxonomically challenging ant genus that is badly in need of review. Most species are very small and soft bodied and current descriptions regularly lack clarity making species identifcation a daunting task. Furthermore, the monophyly of Brachymyrmex has not been established and the relationships among its species and with closely related genera are poorly understood. Most species of Brachy-myrmex are monomorphic, but two dimorphic species have been assigned to the genus before. Here, we redescribe these dimorphic taxa, B. pilipes and B. micromegas, and describe three new monomorphic species, B. brasiliensis sp. n., B. delabiei sp. n. and B. feitosai sp. n. All fve species occur in Brazil and have tumuliform metathoracic spiracles, which are lacking in other Brachymyrmex species. We discuss dimorphism and its evolution in the genus and provide a distribution map, illustrations and a species identifcation key based on workers. © C.M. Ortiz, F. Fernández.