Morphological and genetic evidence support the species status of Lasioglossum angustifrons, distinct from L. punctatissimum (Hymenoptera: Halictidae)

Europe hosts a remarkable diversity of wild bees, among which the genus Lasioglossum Curtis, 1833 ranks among the most species rich. The definition of the taxonomic status of many species within this genus remains challenging. In this work, we reassessed the subspecific status of Lasioglossum (Hemihalictus) punctatissimum angustifrons (Vachal, 1892) through a comprehensive analysis integrating morphology, molecular and distributional data. Phylogenetic reconstruction using a Maximum Likelihood tree and three independent species delimitation models revealed that L. angustifrons forms a distinct and well-supported lineage, separated from L. punctatissimum (Schenck, 1853) and related taxa by significant genetic distances. Morphological examination confirmed stable diagnostic features, including reddish metasomal terga, finer punctation on the scutum, and the specific appearance of the male genitalia. Lasioglossum angustifrons is mainly distributed along the coastal regions of Western North Africa, extending to the Iberian Peninsula and Sicily, with a few inland records. Based on congruent morphological and molecular evidence, Lasioglossum (Hemihalictus) angustifrons stat. nov. is best treated as a species than a subspecies. This revision resolves a long-standing taxonomic ambiguity in the Lasioglossum punctatissimum complex and contributes to a more accurate understanding of species diversity in Mediterranean halictine bees.