Revision of the status of some genus-level water mite taxa in the families Pionidae Thor, 1900, Aturidae Thor, 1900, and Nudomideopsidae Smith, 1990 (Acari: Hydrachnidiae) Author Smith, Ian M. Author Cook, David R. Author Gerecke, Reinhard text Zootaxa 2015 3919 1 111 156 journal article 10.11646/zootaxa.3919.1.6 4c40552e-e778-4d8e-a6b7-9662436cadc2 1175-5326 244587 F711CA99-1B2C-4E18-9F4B-7521D38D2303 Genus Tiphys Koch, 1836 Tiphys (in part): Cook, 1974a , pp. 281–282, figs. 1191–1198 , 1200–1202 . Tiphys (in part): Smith, 1976 , pp. 49–52, 82–85, 90, 92, figs. 34–46. Tiphys (in part): Wainstein, 1980 , pp. 193–197, figs. 647–653, 661–665. Tiphys (in part): Smith & Cook, 1991 , pp. 554, 579, figs. 16.172, 16.173, 16.176, 16.179. Tiphys (in part): Smith et al ., 2001 , pp. 582, 615, figs. 126–128, 130. Tiphys (in part): Smith et al ., 2010 , pp. 524, 556, figs. 15.126–15.128, 15.130, 15.333, 15.336. Diagnosis. Larva : Character states of the subfamily Tiphyinae. Third coxal plate with transverse muscle attachment scar present. Excretory pore plate nearly circular with setae ps1 well anterior to setae ps2 ; excretory pore sessile. Adults (modified from Smith 1976 ): Character states of subfamily Tiphyinae. Fourth coxal plates with large, anteriorly concave projections covering insertions of fourth legs. Pedipalp with segments short and stout to long and slender and tibia with a short, peg-like seta or a long, blade-like seta distomedially that may be borne on a prominent projection. Genital field bearing three to six pairs of acetabula. Males with genital acetabula relatively close together and borne on triangular acetabular plates that either completely encircle gonopore or nearly encircle gonopore but are separate from pregenital sclerite anteriorly, and do not extend laterally beyond posteromedial angles of fourth coxal plates; second leg with tibia lacking spatulate setae distoventrally and fourth leg with genu greatly expanded and usually bearing several to many slender or blade-like setae anteriorly and several to many long swimming hairs on ventral edge. Females with genital acetabula relatively close together and borne on triangular acetabular plates and with second and third acetabula on each side usually not forming a row near posterior edge of plate that is nearly at right angles to long axis of idiosoma. Type species. Tiphys sagulatus Koch. Species included. Numerous species listed by K.O. Viets, 1987 but excluding members of Acercopsis and Pionides . There are many undescribed species of Tiphys from North America in the Canadian National Collection of Insects and Arachnids. Distribution. Holarctic. Discussion. Cook (1974a) had a broad concept of Tiphys that included Acercopsis and Pionides as subgenera. Smith (1976) elevated Pionides to full generic rank and considered the species of Acercopsis (his Tiphys pistillifer group) as the sister group of all other species of Tiphys . Here we propose a restricted concept of Tiphys that excludes both Acercopsis and Pionides . This genus will be subject to further revision when the species level taxonomy of the North American fauna is sufficiently well known to permit the proposal of species groups that are demonstrably holophyletic.