Axonopsis sp., from here.

Belongs within: Aturidae.

Axonopsis is a genus of water mites found in Eurasia and North America.

Characters (from Wolcott 1905): Body oval, with a chitinous covering with a median cleft in the posterior margin; palpi with segment 2 thickened, segment 4 with a convex flexor surface on which, beyond the middle, are two strong hairs borne on small papillae, segment 5 pointed and ending in two small claws; epimera forming an epimeral plate, separated anteriorly by a constriction from the rest of the body, all epimera fused with each other and with the posterior ventral chitin, the anterior ends of epimerae I strongly produced, extending considerably beyond the capitulum, the margins of the anterior epimera serrate and bearing hairs; legs short, II to IV with a few swimming-hairs; genital area at the posterior end of the body, including two plates each with four acetabula; no sexual dimorphism.

<==Axonopsis Piersig 1893S86
    |  i. s.: A. complanataBK91
    |         A. setonensisWL09
    |--A. (Axonopsis) [incl. Pseudaxonopsis Cook 1963]S86
    |    |--A. (A.) bimaculata Cook 1974S86
    |    |--A. (A.) cogitatus Biesiadka 1975S86
    |    |--A. (A.) longipalpis Imamura 1956S86
    |    |--A. (A.) orghidani Petrova 1967S86
    |    |--A. (A.) phreaticola Cook 1967S86
    |    |--A. (A.) sabulonis Cook 1974S86
    |    |--A. (A.) uchidai Imamura 1956S86
    |    `--A. (A.) yokotai Imamura 1957S86
    |--A. (Brachypodopsis Piersig 1903)S86
    |    |--A. (B.) arpeda Cook 1974S86
    |    |--A. (B.) bicornis Orghidan, Gruia & Iavorschi 1981S86
    |    |--A. (B.) boutata Cook 1980RFF05
    |    |--A. (B.) columbicola Lundblad 1953RFF05
    |    |--A. (B.) dapsila Cook 1974S86
    |    `--A. (B.) kasamensis Imamura 1977S86
    |--A. (Cubaxonopsis Orghidan, Gruia & Iavorschi 1981)S86
    |    |--A. (C.) bispinulatus Orghidan, Gruia & Iavorschi 1981S86
    |    |--A. (C.) cavifrons Orghidan, Gruia & Iavorschi 1981S86
    |    `--A. (C.) robustipalpis Orghidan, Gruia & Iavorschi 1981S86
    |--A. (Hexaxonopsis Viets 1926)S86
    |    |--A. (H.) heteropalpis Imamura 1956S86
    |    |--A. (H.) inferorum Motas & Tanasachi 1947S86
    |    |--A. (H.) miurai Imamura 1956S86
    |    |--A. (H.) monstrabilis Biesiadka 1975S86
    |    |--A. (H.) serrata Walter 1928S86
    |    `--A. (H.) subterraneus Uchida & Imamura 1953S86
    |--A. (Navinaxonopsis Orghidan, Gruia & Iavorschi 1981)S86
    |    `--A. (N.) guajabicus Orghidan, Gruia & Iavorschi 1981S86
    |--A. (Paraxonopsis Motas & Tanasachi 1947)S86
    |    |--A. (N.) mikawaensis Imamura 1957S86
    |    |--A. (N.) panduvarna Cook 1967S86
    |    |--A. (N.) pumila Cook 1974S86
    |    `--A. (N.) vietsi Motas & Tanasachi 1947S86
    `--A. (Vicinaxonopsis Cook 1974)S86
         |--A. (V.) californica Cook 1974S86
         |--A. (V.) cooki Orghidan, Gruia & Iavorschi 1981S86
         |--A. (V.) motasi Orghidan, Gruia & Iavorschi 1981S86
         `--A. (V.) solangei Orghidan, Gruia & Iavorschi 1981S86

*Type species of generic name indicated


[BK91] Biesiadka, E., & W. Kowalik. 1991. Water mites (Hydracarina) as indicators of trophy and pollution in lakes. In: Dusbábek, F., & V. Bukva (eds) Modern Acarology: Proceedings of the VIII International Congress of Acarology, held in České Budĕjovice, Czechoslovakia, 6–11 August 1990 vol. 1 pp. 475–481. SPB Academic Publishing: The Hague.

[RFF05] Rosso de Ferradás, B., & H. R. Fernández. 2005. Elenco y biogeografía de los ácaros acuáticos (Acari, Parasitengona, Hydrachnidia) de Sudamérica. Graellsia 61 (2): 181–224.

[S86] Schwoerbel, J. 1986. Acari: “Hydrachnellae”. In: Botosaneanu, L. (ed.) Stygofauna Mundi: A Faunistic, Distributional, and Ecological Synthesis of the World Fauna inhabiting Subterranean Waters (including the Marine Interstitial) pp. 652–696. E. J. Brill/Dr W. Backhuys: Leiden.

[WL09] Walter, D. E., E. E. Lindquist, I. M. Smith, D. R. Cook & G. W. Krantz. 2009. Order Trombidiformes. In: Krantz, G. W., & D. E. Walter (eds) A Manual of Acarology 3rd ed. pp. 233–420. Texas Tech University Press.

Wolcott, R. H. 1905. A review of the genera of the water-mites. Transactions of the American Microscopical Society 26: 161–243.


  1. Hi dear colleague,
    It is really a difficult enterprise to deal with taxonomy as it is quite complicated, and may change a lot… Concerning this specific subject (thanks for it), I advise you a new publication where we learn that, for example, Paraxonopsis has been raised to the rank of genera instead of sub-genera.
    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) – IAN M. SMITH, DAVID R. COOK & REINHARD GERECKE
    The Paraxonopsis romijni species is missing in your tree and maybe other ones…
    Anyway many thanks for you blog and the gorgeous job it requires !
    I am really one of your colleagues but more "specialised" (how funny it sounds) on Mites and Parasites.
    Cheers !

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