Introduction of the Exocelina ekari-group with descriptions of 22 new species from New Guinea (Coleoptera, Dytiscidae, Copelatinae)

Abstract. The Exocelina ekari-group is here introduced and defined mainly on the basis of a discontinuous outline of the median lobe of the aedeagus. The group is known only from New Guinea (Indonesia and Papua New Guinea). It contained four species to date: Exocelina astrophallus (Balke, 1998), Exocelina atowaso (Shaverdo, Sagata & Balke, 2005), Exocelina munaso (Shaverdo, Sagata & Balke, 2005), and Exocelina polita (Sharp, 1882). Twenty two new species are described herein: Exocelina alexanderi sp. n., Exocelina anggiensis sp. n., Exocelina arfakensis sp. n., Exocelina bifida sp. n., Exocelina brahminensis sp. n., Exocelina bundiensis sp. n., Exocelina edeltraudae sp. n., Exocelina ekari sp. n., Exocelina eme sp. n., Exocelina evelyncheesmanae sp. n., Exocelina hansferyi sp. n., Exocelina irianensis sp. n., Exocelina kakapupu sp. n., Exocelina knoepfchen sp. n., Exocelina oceai sp. n., Exocelina pseudosoppi sp. n., Exocelina soppi sp. n., Exocelina unipo sp. n., Exocelina utowaensis sp. n., Exocelina waigeoensis sp. n., Exocelina weylandensis sp. n., and Exocelina wondiwoiensis sp. n. The lectotype of Copelatus politus Sharp, 1882 is designated. A checklist and identification key to all species of the group are provided and important diagnostic characters (habitus, color, male antennae and protarsomeres 4–5, median lobes and parameres) are illustrated. Data on the distribution and habitat requirements are given. Representatives of the Exocelina ekari-group are so far mostly known from lowland to lower montane habitats of the northern and central parts of New Guinea, the group is less diverse in higher altitudes.