Dineutus (Subgenus Rhombodineutus) Ochs, 1926

Discussion. Rhombodineutus species are moderate sized, broadly ovate gyrinids that are typical inhabitants of rocky upland streams in the foothill and lower montane zones of New Guinea. They may also occur in lowland alluvial forests, but only along the inner margins of alluvial outwash plains where the creeks still retain a reasonable rate of flow velocity upon exiting the adjacent mountain foothills. Species are generally intermittent in their distribution, but often quite abundant along the reaches where encountered. Up to three species may occur at a given site, although in most instances only a single species will be present.