Faunal inventory and illustrated taxonomic keys to aquatic Coleoptera (Arthropoda: Insecta) of the northern Western Ghats of Maharashtra, India

Following several surveys of aquatic Coleoptera during 2013–2018 in northern Western Ghats, India, we hereby provide an illustrated checklist with modified keys to the species of families Dytiscidae, Gyrinidae, Noteridae, and Hydrophilidae. To date, we have collected 69 species of true water beetles, adding new occurrence records for two species to the fauna of the state. Keys are modified from the works of various authors. Distribution records are provided with district specific records for Maharashtra. Keys, species lists, and distribution records are based on our survey results. Species were identified following the works of various authors, and affirmed by dissecting male genitalia. Provided with keys are habitus images, images of male genitalia for 59 species, and digital drawings & scanning electron micrographs of taxonomically important structures wherever necessary. These surveys were conducted to revive the work on aquatic beetles that have been neglected for about 40 years, and to prepare a revised checklist.