Molecular species delimitation and historical biogeography among species of the genus Partamona (Hymenoptera: Apidae: Meliponini), with emphasis on the Eastern group from South America

The stingless bees of the genus Partamona comprise 32 recognized species, all endemic to the Neotropical region, ranging from Mexico to southern Brazil. This study is the first to examine species delimitation, phylogenetic relationships, and divergence-time estimates within the Partamona Eastern group. Of the 21 species in this group, 19 were included in our analysis. Utilizing both mitochondrial and nuclear markers, a multispecies coalescence model identified 19 molecular operational taxonomic units, 13 of which correspond perfectly to the nominal species as initially defined. We find that the Partamona Eastern group is monophyletic and consists of three distinct clades, with relationships among species differing significantly from previous classifications. Divergence-time estimates suggest that the Eastern group originated in the Pliocene, with substantial diversification occurring during the Pleistocene, potentially influenced by shifts in rainforest and dry forest distributions and riverine barriers in the Amazon region. We propose three major dispersal events across biomes. Given these findings, a comprehensive review of the genus, particularly the Eastern clade, is necessary to reassess the current classification using an integrative approach.