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 Brachypoda -like mites ( sensu Cook, 1974) Brachypoda -like mites Cook, 1974a , pp. 337–342, figs. 1431–1457 , 1460. Diagnosis. Larva (modified from Smith 1977b , 1984): Character states of subfamily Axonopsinae. Third coxal plate with medial coxal apodeme present or absent and with transverse muscle attachment scar present or absent. Posterior edge of third coxal plate convex or nearly straight, and lacking or bearing prominent projection that may be elaborate when present. Excretory pore plate much larger than excretory pore and nearly circular, triangular, quadrangular, or broadly obcordate in shape, bearing setae ps1, ps2 , and, in some cases, h2 posterolaterally with ps2 displaced anteriorly and/or medially; excretory pore sessile. Numbers of setae on leg segments as follows: ITi 8 (seta Ti10 absent) or 9; ITa 11 (setae Ta8 and Ta14 absent) or 12 (seta Ta14 absent); IITa 11 (setae Ta8 and Ta14 absent) or 12 (seta Ta14 absent); IIITa 10 (seta Ta14 absent). Adults (modified from Cook 1974a ): Character states of Axonopsinae (see Cook 1974a ). Idiosoma with dorsal shield entire and separated from ventral shield anteriorly; with or without a slight bulge posterior to midlength bearing two enlarged glandularia with extremely long associated setae. Ventral shield on each side bearing a ridge that originates at lateral end of suture line between third and fourth coxal plates and extends anterolaterally; with or without a pronounced ridge extending anterolaterally from genital field in males. Coxal plates with all setae slender; fourth coxal plate with opening for insertion of fourth leg lacking ventral projections and usually without condyles. Genital field bearing three or four pairs of acetabula on acetabular plates that are fused with ventral shield in males but separate from ventral shield in females; genital field of males located either near posterior end of ventral shield or well anterior to posterior edge of ventral shield, and either relatively compact, with acetabula not extending laterally beyond level of insertion of fourth leg and without a patch of long setae immediately lateral to acetabula, or relatively wide, with acetabula extending laterally into region beyond level of insertion of fourth leg and with a patch of long setae immediately lateral to acetabula. Excretory pore borne on dorsal shield near posterior edge, or on separate small platelet posterior to dorsal shield. Gnathosomal setae small. Pedipalp femur usually bearing a distoventral projection and tibia usually bearing a thick seta on a ventral projection (exception: genus Woolastookia ). Fourth leg of males with segments unmodified or variously modified. Genera included. Brachypoda Kramer, 1875 , Estellacarus Habeeb, 1954 , Neobrachypoda Koenike, 1914 , Parabrachypoda Viets, 1929 ( stat . nov .), Ocybrachypoda Cook, 1974 ( stat . nov .), Woolastookia Habeeb, 1954 . Distribution. Holarctic (Eurasia, North America ). Proposed changes. Elevation of Parabrachypoda Viets, 1929 , and Ocybrachypoda Cook, 1974 from subgenera of Brachypoda Kramer, 1875 to full generic status, transfer of species previously placed in subgenus Hemibrachypoda Viets, 1937 from genus Brachypoda to genus Parabrachypoda , and reduction of status of Hemibrachypoda to a synonym of Parabrachypoda . Discussion. Cook (1974a) characterized the Brachypoda -like mites as a distinct group of Axonopsinae including the genera Brachypoda , Neobrachypoda , Estellacarus , and Woolastookia . He treated Hemibrachypoda , Parabrachypoda , and Ocybrachypoda as subgenera of Brachypoda . Here we propose to retain the four genera recognized by Cook, elevate Parabrachypoda and Ocybrachypoda from subgenera of Brachypoda to full genera, transfer the species previously placed in the subgenus Hemibrachypoda from Brachypoda to Parabrachypoda , and reduce Hemibrachypoda to a synonym of Parabrachypoda , to reflect their phylogenetic affinities.