Species delimitation and sex associations in the bee genus Thygater, with the aid of molecular data, and the description of a new species

Thygater Holmberg 1884, a Neotropical bee genus included in the tribe Eucerini, is distributed from Argentina to Mexico, was last revised almost 50 years ago, and included 30 species. Significant problems in Thygater taxonomy are like those found in other bee taxa: sexual dimorphism (sometimes accentuated); large intraspecific variation in some taxa, especially in color patterns; great similarity among putative recently-diverging species; and scarcity of specimens for study of several apparently rare species. These problems hinder the correct delimitation of species boundaries and could result in an underestimated number of species and incorrect association of sexes. In this taxonomic and phylogenetic study of the genus, morphological and molecular evidence are considered together to elucidate the taxonomy of several Brazilian species of Thygater. The analyses allowed the description of two new species (one already described and other described here), additional support for the synonyms proposed elsewhere and sex associations for several species.