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

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: E. astrophallus (Balke, 1998), E. atowaso (Shaverdo, Sagata & Balke, 2005), E. munaso (Shaverdo, Sagata & Balke, 2005), and E. polita (Sharp, 1882). Twenty two new species are described herein: E. alexanderi sp. n., E. anggiensis sp. n., E. arfakensis sp. n., E. bifida sp. n., E. brahminensis sp. n., E. bundiensis sp. n., E. edeltraudae sp. n., E. ekari sp. n., E. eme sp. n., E. evelyncheesmanae sp. n., E. hansferyi sp. n., E. irianensis sp. n., E. kakapupu sp. n., E. knoepfchen sp. n., E. oceai sp. n., E. pseudosoppi sp. n., E. soppi sp. n., E. unipo sp. n., E. utowaensis sp. n., E. waigeoensis sp. n., E. weylandensis sp. n., and E. 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 E. 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