Brachygasterina Macquart, an endemic South American genus, is revised to include Brachygasterina andina sp. nov. from Ecuador (Pichincha). All six species are redescribed, including B. stuebeli that was recently transferred to this genus. A cladistic analysis was performed including five of the six species of the genus and using Delia platura (Meigen), an anthomyiid fly, and Palpibracus veneris (Bigot) as outgroup taxa. Four most parsimonious cladograms were found, all supporting the monophyly of the genus, as previously stated in the literature. According to the selected cladogram, the phylogenetic relationships of Brachygasterina species are as follows: (D. platura (P. veneris ((B. andina, B. stuebeli) (B. major (B. valdiviensis, B. violaceiventris))))). A cladistic biogeographic analysis of the genus was conducted and is discussed. The pattern revealed by the species of Brachygasterina can be explained by vicariant events involving two lineages of Brachygasterina and the evolution of the Andes.
Taxonomic comments on Megachile subgenus Chrysosarus (Hymenoptera: Megachilidae)
