Abstract
Material from the type localities of most described species of Papuanatula and rich material newly collected across New Guinea and on the island Sulawesi form the bases for this comprehensive study of the genus, including the description of a new subgenus Papuafiliolasubgen. nov. and 20 new species. Species delimitation is based on morphology of larvae and partly also imagos, supported by mitochondrial DNA data (COI) for some of the species. The total number of species is augmented from six to 26. The genus has a disjunct distribution on the islands New Guinea (incl. New Britain) and Sulawesi. A key to the larvae of all species is provided. Morphological similarities, the relationship of Papuanatula to other genera of Baetidae, and possible explanations for the high diversity in New Guinea are discussed.