Agapostemon fasciatus Crawford (Hymenoptera, Halictidae), a valid North American bee species ranging into southern Canada

Sweat bees of the genus Agapostemon Guérin-Méneville, 1844 (Hymenoptera: Halictidae) are common and widespread in the Americas. Despite distinct morphological characters that were recognised in earlier taxonomic treatments, Agapostemon fasciatus Crawford, 1901 has been considered a variety of A. melliventris Cresson, 1874 since the 1930s and later placed into synonymy under A. melliventris in the early 1970s.A more detailed study of morphology (including examination of type materials), distribution and genetic data (i.e. DNA barcodes) of these two taxa suggests they are not conspecific. As such, A. fasciatus is resurrected as a valid North American bee species. Agapostemon fasciatus ranges further north in North America than A. mellivenrtis, reaching the southern Prairies Ecozone of Canada (Alberta, Saskatchewan), while most records of A. melliventris are from the south-western United States and northern Mexico. More accurate distributions for both species can be modelled as specimens in collections are identified using the diagnostic features provided. However, additional work is required on the A. melliventris species complex in the southern United States as genetic data suggest that multiple taxa could be present.

属名 Agapostemon Guérin-Méneville, 1844（膜翅目：蜜蜂科）的汗水蜜蜂在美洲地区分布广泛且较为常见。尽管在早期的分类处理中已识别出明显的形态特征，但自1930年代以来，A. fasciatus Crawford, 1901被认定为A. melliventris Cresson, 1874的一个变种，并在20世纪70年代初被归入同义词下，成为A. melliventris。然而，对这些两个类群形态学（包括典型材料检查）、分布和遗传数据（例如DNA条形码）的深入研究表明，它们并非同种。因此，A. fasciatus被重新确认为一个有效的北美蜜蜂物种。A. fasciatus在北美洲的分布范围比A. melliventris更广，可达加拿大南部大草原生态区（阿尔伯塔省、萨斯喀彻温省），而A. melliventris的大多数记录来自美国西南部和墨西哥北部。通过使用提供的诊断特征，可以对两种物种的更精确分布进行建模。然而，由于遗传数据表明可能存在多个类群，因此需要对美国南部的A. melliventris物种复合体进行进一步的研究。