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 Erebaxonopsis Motaş & Tanasachi, 1947 Erebaxonopsis : Cook, 1974a , pp. 336–337, 459–460, figs. 1419, 1421, 1423–1426 . Erebaxonopsis : Smith & Cook, 1991 , p. 577. Erebaxonopsis : Smith et al ., 2001 , p. 614, figs. 360, 361. Erebaxonopsis : Smith et al ., 2010 , p. 555, figs. 15.361, 15.362. Diagnosis. Larva : Unknown. Adults (modified from Cook 1974a , 1974b ): Character states of Axonopsis -like mites. Dorsal and ventral shields separate anteriorly; lacking caudal development posteriorly. Dorsal furrow lacking glandularia and lyrifissures. Dorsal shield bearing seven pairs of glandularia (some of which apparently lack gland portion) with one pair flanking excretory pore. Ventral shield on each side with ridge originating at lateral end of vestigial suture line between third and fourth coxal plates extending anteriorly to anterior edge of shield; anterior coxal plates relatively wide and rugose, but lacking hook-like projections; fourth coxal plate lacking glandularia in region between genital field and opening for insertion of fourth leg. Genital field bearing four pairs of acetabula with anterior and posterior pair flanking gonopore and two other pairs more lateral in postion. Suture lines between genital field and ventral shield obliterated. Gnathosoma with mouth opening terminal in position; gnathosomal apodemes moderately long. Pedipalp tibia relatively long and slender, lacking ventral projection, and bearing two slender setae distally; tarsus shorter than tibia. Fourth leg with segments flattened and with telofemur much smaller than other segments. Type species. Erebaxonopsis brevipes Motaş & Tanasachi. Species included. Erebaxonopsis brevipes Motaş & Tanasachi (Europe) , E. amamiensis Imamura ( Japan ) , E. morimotoi (Imamura) ( Japan ) , E. nearctica Cook (western North America ). Distribution. Holarctic (Eurasia, western North America ). Discussion. Cook (1974a , 1974b ) treated Erebaxonopsis as a separate genus. Smith & Cook (1991) and Smith et al . (2001 , 2010) followed that treatment here, as we do here.