Abstract
Since 2010, the Mátra Museum of the Hungarian Natural History Museum has conducted a long-term research program to explore the biodiversity and collect data of selected groups of insects and partly other animals on the island of Batanta (Indonesia, West Papua). During this research project, numerous mayflies of different stages were collected as well. In this study, mayflies of the highly diverse genus Papuanatula (Ephemeroptera, Baetidae) collected in Batanta between 2014 and 2025 were investigated. Six new species were discovered, four belonging to the subgenus Papuanatula s. str., P. batantaraja sp. nov., P. cukiclara sp. nov., P. cataracta sp. nov., P. batanlenos sp. nov., and two to the subgenus Papuafiliola, P. horvathrobi sp. nov. and P. longabranchias sp. nov. Their larval stages are described and illustrated. Additionally, imagos and subimagos of two of the new species are described as well, and the eggs of one species. Furthermore, a new species of Papuanatula from another region of New Guinea is described. For most species, the species delimitation is also supported by mitochondrial DNA data (COI). Keys to the larvae of all species per subgenus or species group relevant for Batanta are presented. The total number of Papuanatula species is augmented to 33.