Taxonomic revision of New Guinea diving beetles of the Exocelina danae group, with the description of ten new species (Coleoptera, Dytiscidae, Copelatinae)

Ten new species of Exocelina Broun, 1886 from New Guinea are described: Exocelina andakombensissp. n., Exocelina garainasp. n., Exocelina injiensissp. n., Exocelina kabwumensissp. n., Exocelina marawagasp. n., Exocelina posmanisp. n., Exocelina tekadusp. n., Exocelina variratasp. n., Exocelina wareagasp. n., and Exocelina woitapensissp. n. All of them together with five already described species are united into the newly defined Exocelina danae-group (with Exocelina miriae-subgroup), a polyphyletic complex of related species with lateral setation on the median lobe. In the light of newly available material, all previously described species of the Exocelina rivulus-group are considered to belong to a single species, Exocelina damantiensis (Balke, 1998), which is now placed into the Exocelina danae-group, and three new synonyms are therefore proposed: Exocelina madangensis (Balke, 2001) syn. n., Exocelina patepensis (Balke, 1998) syn. n., and Exocelina rivulus (Balke, 1998) syn. n. Exocelina tarmluensis (Balke, 1998) syn. n. is a junior synonym of Exocelina danae (Balke, 1998). Redescription of Exocelina atratus (Balfour-Browne, 1939) is provided based on its type material. An identification key to all known species of the group is provided, and important diagnostic characters are illustrated. Data on the species distribution are given, showing that whilst most species are local endemics, Exocelina damantiensis is extremely widely distributed.