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Lanthanomelissa has an uncertain taxonomic history, and was formerly treated either as an independent genus or as a subgenus of Chalepogenus. It is endemic to southern South American grasslands, an endangered and poorly known environment. We aimed to understand the origin of these bees in time and space, the influence of Quaternary climatic fluctuations on their current distribution, and the possible link to the southern South American grasslands' history. We inferred phylogenetic relationships in Lanthanomelissa using 37 specimens from all six species and 3430 nucleotides of three mitochondrial and two nuclear genes and estimated divergence times and ancestral geographic range. We modeled species distribution for the current and two past climatic scenarios (LIG, ~120 kya, and LGM, ~21 kya), performing an ensemble with three algorithms in a dataset of 192 georeferenced occurrence points using 19 WorldClim bioclimatic variables. The results support the monophyly of the genus and taxonomic changes, including the species Lanthanomelissa parva n. comb., and the treatment of the goeldianus group of Chalepogenus as the genus Lanthanella. Lanthanomelissa originated at the Oligocene–Miocene border in the Chacoan–Pampean region, and the glacial–interglacial models indicate expansion in the Last Glacial Maximum and retraction in the Last Interglacial. This origin was approximately synchronized with their exclusive floral host, Sisyrinchium (Iridaceae). The diversification of Lanthanomelissa supports the estimated austral expansion of the ancestral southern grasslands in South America before the origin of Cerrado during the late Miocene. Expansion and retraction in distribution during the last glacial–interglacial indicate grasslands distributional shifts through climate cooling and warming periods. [ABSTRACT FROM AUTHOR]

We present a first comprehensive time-calibrated phylogeny for two Neotropical genera of bees, Centris and Epicharis, whose females collect floral oil together with pollen for larval provisioning, and that traditionally have been grouped in the tribe Centridini. Our analyses rely on a matrix of 167 taxa and 4228 aligned nucleotides for the subfamily Apinae, with denser sample of Centris and Epicharis. Centris and Epicharis are strongly supported monophyletic groups, but Centridini is paraphyletic in relation to the corbiculate bees. The inner phylogenetic relationships of Epicharis agree with the current taxonomic classification. In Centris, three main clades were recovered, namely the Centris, Trachina and Melacentris groups. Inner relationships in Centris suggest the reinstatement of some subgenera and proposition of new ones. Early diversification of Centris and Epicharis took place at the tropical regions of South America. Epicharis and the Melacentris group in Centris mostly diversi- fied in that region, expanding over Central America and tropical North America only recently in the last 3 My. The groups Trachina and Centris present a complex biogeographic history, with expansions to the Nearctic region, the Antilles, and temperate regions of South America in the late Oligocene and Miocene. [ABSTRACT FROM AUTHOR]