Hispidosperchon Thor, 1901

Sabatino, Antonio Di, Gerecke, Reinhard, Gledhill, Terence & Smit, Harry, 2009, On the taxonomy of water mites (Acari: Hydrachnidia) described from the Palaearctic, part 2: Hydryphantoidea and Lebertioidea, Zootaxa 2266, pp. 1-34 : 21

Subgenus Hispidosperchon Thor, 1901

Mixosperchon K. Viets, 1926 , nov. syn.

Discussion: The name source for the subgenus Mixosperchon was the presence of an areolate integument structure as typical for Hispidosperchon -species, mixed with papillae as found in Sperchon s.str. (K. Viets 1926l). Cook (1974) made the additional attempt to separate the two taxa on the basis of the presence of a gland pore on Cx-III (present in Hispidosperchon , absent in Mixosperchon and Sperchon s.str.). However, both characters are found differently expressed in species which are obviously closely related and thus cannot be applied for definition of subgenera in Sperchon: Examples of such pairs of species pairs are: (1) S. longirostris Koenike, 1895 (with glands on Cx-III) and S. squamosus Kramer, 1879 (lacking such glands), both representatives of the distinct squamosus species group (with long gnathosomal rostrum and inflated P- 2) and (2) S. setiger Thor, 1898 (with simply areolate integument) and S. algeriensis Lundblad, 1942 (combining papillae and areolation), both representatives of the setiger species group (with palps rotated in an oblique horizontal plane and development of ventral setae on P-3). In Sperchon s.str. the integument is papillate or with rugose lines, and generally completely smooth or with very small sclerotized muscle attachments restricted to the dorsal surface. These contradictions induced K.Viets (1956) to break his own subgenus concept and shift S. setiger to Hispidosperchon . Species attributed to Mixosperchon and Hispidosperchon have in common not only the areolate ground pattern of the integument structure, but also the presence of several pairs of dorsal (which in males of several species fuse to a dorsal shield) and ventroposterior plates. Mixosperchon is a polyphyletic assemblage of Hispidosperchon -species and cannot be accepted as a subgenus in Sperchon .