Hydrodroma pilosa Besseling, 1940

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 : 2

Hydrodroma pilosa Besseling, 1940

Material examined: South Germany, Radolfzell, Lake Mindelsee coll. Meyer 1980 (17/25/0); the same site coll Gerecke 2006 (24/56/4).

Remarks: The detailed description of the life cycle and development of Hydrodroma despiciens was published by Meyer (1985) immediately before Wiles (1985) cleared up the taxonomic situation of the European (sub)species of the genus. In a later paper, Meyer (1989) indicated that the population on which her study was based, represented Hydrodroma despiciens pilosa , a subspecies raised to species rank by Gerecke (1991). A revision of both slide material from Meyer's PhD thesis and newly collected populations confirms that exclusively Hydrodroma pilosa was, and still is, present in the Mindelsee. In the course of this study, further characters were detected that separate H. pilosa from H. despiciens : Integument papillae are sharply pointed (in H. despiciens apically rounded) and more acetabula 6-8 (in H. despiciens 4-6) lie in parallel rows where the genital flaps have their maximum width. These differences show that the two taxa should be considered separate species. Information so far published on the biology of Hydrodroma despiciens , might in reality refer to H. pilosa , or cannot be interpreted with certainty. Consequently, with regard to its life cycle, H. despiciens is still a mostly unknown species.