DNA barcoding and male genital morphology reveal five new cryptic species in the West Palearctic bee Seladonia smaragdula (Vachal, 1895) (Hymenoptera: Apoidea: Halictidae).

Several forms or variants have long been recognized in the West Palearctic sweat bee Seladonia smaragdula (Vachal, 1895). Using DNA barcoding and morphological characters, primarily of the male genitalia, these variants are here recognized and described as five new species: S. gemmella Pauly sp. nov., S. submediterranea Pauly sp. nov., S. orientana Pauly & Devalez sp. nov., S. phryganica Pauly & Devalez sp. nov., and S. cretella Pauly & Devalez sp. nov. Also, we designate a lectotype for Halictus smaragdulus Vachal, consider Seladonia butea (Warncke, 1975) and S. morinella (Warncke, 1975) as nomina dubia, and discuss the identity of the Seladonia specimens from Australia currently determined as S. smaragdula.