Notes on South American stingless bees of the genus Scaptotrigona (Hymenoptera: Apidae), Part I: short-bristle species, the tubiba species group

Among the diversity of the stingless bee genus Scaptotrigona Moure (Apinae: Meliponini) there are a set of distinctive species distinguished from all others by their sparse and short bristles on the head and mesosoma, here treated as the tubiba species group. Four species are included in this group, two of which are new to Science: Scaptotrigona pasiphaea, sp. n., from southern Amazonian Peru, and S . silviae, sp. n., from eastern and southeastern Brazil. The remaining two species are S . tubiba (Smith) and S . affabra (Moure). A key is provided for their identification.