The water mites of the genus Hydrodroma (Acari, Hydrachnidia, Hydrodromidae) in Europe and Africa

Abstract

Neotypes are designated for Hydrodroma despiciens (Muller, 1776) and H. pilosa Besseling, 1940, lectotypes for H. torrenticola (Walter, 1908) and H. capensis (K. Viets, 1914). Diagnostic features and morphological variability of these two species, as well as of H. torrenticola and H. perreptans, are discussed. New morphological details are presented for H. trigonometrica Walter, 1928, H. ocellata Walter & Bader, 1952 (here considered a species incerta), H. liberiensis Cook, 1966 and H. reinhardi Pesic, 2002. After revision of museum collections, numerous older identifications are corrected. Concerning material from Europe, a high degree of confusion is found between H. despiciens, H. torrenticola and H. pilosa. For H. despiciens, all records from Africa, as well as species identifications from Wisconsin (U.S. A) and Argentina are rejected. This species, formerly considered cosmopolitan, is actually ascertained only from the European continent. Hydrodroma pilosa is recorded for the first time from Africa (Algeria). Most published records of H. capensis refer to other, in several cases probably undescribed species; recognized material derives exclusively from the terra typica in the African Cape Province. An identification key is given for the species known from Europe and Africa.