Oxus Kramer, 1877

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 : 19

Oxus Kramer, 1877

Frontipoda Koenike, 1891 : Besch (1964).

Discussion: The genera Oxus and Frontipoda were very distinct in Europe, the idiosoma of Frontipoda being laterally compressed, while the idiosoma of Oxus was more rounded. Moreover, the dorsal furrow is wide in Oxus and narrow in Frontipoda . A third genus, Flabellifrontipoda , was characterised by comb-like claws. This genus has recently been lowered to the rank of subgenus in Frontipoda ( Smit 2002) . With the description of many more species from the Southern Hemisphere, the differences between Oxus and Frontipoda have become blurred. One of the first authors to comment on this was Lundblad (1941). He suggested that it might be necessary to synonymize the two genera, or have Frontipoda lowered in rank to a subgenus of Oxus . Besch (1964) synonymized the two genera, but few acarologists followed this. More authors discussed this problem, e.g. Viets (1959) and Cook (1986). The latter author made an artificial separation between the two genera, Oxus having four or less glandularia on the lateral side, while Frontipoda has five or more pairs of glandularia on the lateral side. But even this artificial separation was unsatisfactory, as one Frontipoda species with three glandularia on the lateral side remained.

We are of the opinion that the separation of Oxus and Frontipoda can no longer be maintained, and therefore follow Besch (1964) in his synonymization of the two genera.