A review of the New Zealand Berosus (Coleoptera: Hydrophilidae) with descriptions of three new species

Abstract

The New Zealand species of the water scavenger beetle genus Berosus Leach, 1817 are reviewed based on freshly collected material and museum specimens. Four species are recognized: Berosus pallidipennis (Sharp, 1884) widespread in the North and South Islands, B. muellerorum sp. nov. from the eastern part of the North Island, and B. halasi sp. nov. and B. maru sp. nov., both endemic to central part of South Island. The synonymy of B. mergus Broun, 1886 with B. pallidipennis is confirmed and lectotypes for both taxa are designated. The larval morphology of B. pallidipennis and B. muellerorum is briefly discussed. Distributional data of all species are reported and illustrated, indicating a noticeable lack of Berosus species in the northern part of North Island and in Stewart Island and the presence of two rare species in the South Island, east of Southern Alps. An identification key to New Zealand species of the genus is provided