Axonopsis Piersig, 1893

Smith, Ian M., Cook, David R. & Gerecke, Reinhard, 2015, 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), Zootaxa 3919 (1), pp. 111-156 : 138-139

Genus Axonopsis Piersig, 1893

Axonopsis (Axonopsis) : Cook, 1974a, pp. 331–332, figs. 1377–1379, 1381, 1382, 1384–1386. Axonopsis: Cook, 1974b , pp. 55–58, figs. 78–85.

Axonopsis (in part): Smith & Cook, 1991, p. 577.

Axonopsis (in part): Smith et al., 2001, p. 614.

Axonopsis (in part): Smith et al., 2010, p. 555.

Axonopsis (Axonopsis) : Pešić, Smit & Saboori, 2012, pp. 52–54, fig. 38.

Diagnosis. Larva: Partially described by Piersig (1897 –1900), but insufficiently known to permit listing of diagnostic character states.

Adults (modified from Cook 1974a, 1974b): Character states of Axonopsis -like mites. Dorsal and ventral shields broadly fused anteriorly; lacking caudal development posteriorly. Dorsal furrow bearing two pairs of glandularia and three pairs of lyrifissures on small platelets. Dorsal shield bearing three or four pairs of glandularia with one pair flanking excretory pore. Ventral shield on each side with ridge originating at lateral end of suture line between third and fourth coxal plates extending anterolaterally to lateral edge of shield; anterior coxal plates relatively wide and 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. Suture lines between genital field and ventral shield well delineated. 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 distoventrally; tarsus shorter than tibia. Fourth leg with segments not flattened and telofemur not reduced in size.

Type species. Axonopsis bicolor Piersig = Axonopsis complanata (Müller) .

Species included. Axonopsis complanata (Müller) (Europe) , A. bimaculata (Cook) (central North America), A. gracilipalpis Viets (Sumatra) , A. hyporheica Pešić, Smit & Saboori ( Iran) , A. indica Cook ( India) , A. keralensis Cook ( India) , A. lundbladi Cook (West Africa), A. magnipalpis Cook (West Africa), A. mediolutea Viets (Java) , A. phreaticola Cook ( India) , A. sabulonis Cook (eastern North America), A. vayitriensis Cook ( India) . Axonopsis longipalpis Imamura from Japan has been tentatively allocated to this genus. There are several undescribed species of Axonopsis from North America in the Canadian National Collection of Insects and Arachnids.

Distribution. Holarctic (Eurasia, North America), India, Southeast Asia, West Africa.

Discussion. Cook (1974a, 1974b) employed a broad concept of Axonopsis including eight subgenera. We are here proposing a very restricted concept of the genus Axonopsis including only species previously allocated to the nominate subgenus. The other seven taxa previously regarded as subgenera of Axonopsis are here either elevated to full generic status or allocated as subgenera to one or another of the newly recognized full genera.