A catalogue of Hydryphantoidea from South America, with information on their geographic distribution and a key to families, subfamilies, genera, subgenera and species (Acariformes, Parasitengonina, Hydrachnidia)

Water mites of the superfamily Hydryphantoidea occur on all continents except Antarctica. Here, after reviewing the history of water mite taxonomy in South America, we provide a catalogue of members of the four hydryphantoid families present in South America: Hydryphantidae, Hydrodromidae, Rhynchohydracari-dae and Thermacaridae. To date, 55 named species have been reported from this region. The great majority of South American hydryphantoids are known exclu-sively as adults, with larvae having been described from only three of the 55 species. We include data on type localities and the known distribution of the species, and provide a key to all taxa reported from South America. We also include molecular data (COI barcodes) for four species representing all three genera of Rhyncho-hydracaridae recorded from the continent: Clathrosperchon punctatus Cook, 1980, C. minor Lundblad, 1937, Clathrosperchonella olovi Castro, Proctor & Lofego, 2020 and Rhynchohydracarus armiger Castro, Proctor & Lofego 2022. We hope that this publication will serve as a resource for future explorations of the diversity of hydry-phantoids in South America and for studies of morphological and molecular evolu-tion of this diverse group of water mites.