An updated checklist of the Hydradephaga of Switzerland (Coleoptera)

An updated checklist of the Swiss species of Hydradephaga (Dytiscidae, Gyrinidae, Haliplidae, Hygrobiidae, Noteridae) is presented and briefly discussed. A total of 139 species is retained as part of the Swiss fauna, while 53 species, which have been recorded in Switzerland in the past, are excluded from this list, either due to insufficient documentation or because their records were based on misidentified material. In contrast to previous works, the present study also provides, for the first time, distribution maps through an online map server for all Hydradephaga species in Switzerland, based on over 43,000 occurrences obtained from specimens held in museums and private collections, as well as literature data. The occurrences of the rarest species of Switzerland, as well as data on species erroneously cited in Switzerland, are presented and discussed.