Hidden Amazonian diversity: integrative taxonomy reshapes the Melipona seminigra species complex (Hymenoptera: Apidae: Meliponini)

Abstract Melipona seminigra is a polytypic complex of stingless bees broadly distributed throughout the Brazilian Amazon and of major ecological and economic importance due to its role in pollination and meliponiculture. Despite the considerable amount of taxonomic information accumulated over time, the identity and boundaries of its constituent forms have remained uncertain. In this study, we conducted an integrative taxonomic assessment based on specimens deposited in three institutional collections, combining traditional morphological analyses with molecular species-delimitation approaches using COI sequences. Our results provide consistent morphological and molecular evidence supporting the elevation of all currently recognized subspecies of M. seminigra to full species status. Furthermore, we describe two new species, Melipona atrofulva sp. nov . and Melipona picea sp. nov ., expanding the known diversity within the complex. We also describe, for the first time, three males and two virgin queens previously unknown for already valid taxa. In addition, we present an illustrated worker-based identification key accompanied by detailed morphological diagnoses and an updated distribution map for the group. Together, these findings provide a refined taxonomic framework for the M. seminigra complex and contribute to a better understanding of species diversity, distribution, and evolutionary relationships within one of the most important groups of Neotropical stingless bees.