Morphology of the male genitalia of Brachymyrmex and their implications in the Formicinae phylogeny

The male genitalia of Brachymyrmex are examined and terminology clarified. We document two conformation groups based on the lateral carina, conformation 1 has a complete lateral carina that reaches the apex of the valviceps and in conformation 2 the lateral carina is broken with the apical end projected dorsally. Previously documented species are evaluated in the context of this new information. We offer support for the movement of Brachymyrmex into the resurrected tribe Myrmelachistini based on the morphology of the penisvalvae, and offer definitive methods of assigning unknown specimens to this genus. This study provides histological methodologies for the preparation, differentiation, and permanent storage of minute ant genitalia structures and the associated musculature.