Antennal sensilla analyses as useful tools in the revision of the sweat-bee subgenus Corynura (Callistochlora) Michener (Hymenoptera: Halictidae)

Although many studies have analyzed the physiology of the antennal sensilla, only a few have used them for systematics. If the abundance and distribution of the different types of sensilla are constant within species, these characters may be used as additional tools in wild bee systematics, especially for the identification of cryptic species. To assess this, we studied the antennal sensilla of the subgenus Corynura (Callistochlora) Michener, which comprises species frequently collected in Chile and the Argentinean Patagonia. Although the species of C. (Callistochlora) play an important role in the pollination of wild and cultivated plants, there are no useful keys to identify them. Here we provide a comparative study of antennal sensilla, as well as a detailed morphological revision of the species, including characters of the genital capsule and the hidden sterna. The sensilla have been important in the resolution of the subgenus, especially in the delimitation of male species. Three valid species are recognized: Corynura aureoviridis Friese, revalidated name, C. chloris Spinola and C. prothysteres Vachal. The male of C. aureoviridis and the female of C. prothysteres are described for the first time. Lectotypes are designated for four names. Synonyms, notes on variation within species, images, distributional data and a key to the species are provided. The study of the antennal sensilla as a potential tool in wild bee systematics is discussed.