On the taxonomy of water mites (Acari: Hydrachnidia) described from the Palaearctic, part 1: Hydrachnidae, Limnocharidae and Eylaidae Author Davids, Kees Author Sabatino, Antonio Di Author Gerecke, Reinhard Author Gledhill, Terence Author Smit, Harry text Zootaxa 2005 1061 36 64 journal article 10.5281/zenodo.170186 d91ae7dd-a600-4f24-a890-7201060d61b6 1175­5326 170186 Hydrachna levigata Koenike, 1897 Species incerta Material examined: Hydrachna levigata , holotype male SMNH 553 ( Type locality: Juist, Niedersachsen, May 1895 ). Discussion: The holotype specimen of Hydrachna levigata , a species recorded only once after the original description ( The Netherlands , Buitendijk 1945 but according to Besseling (1955) not recognisable as H. levigata ), was treated with heat and chemical agents. The consequently strong clearing and deformation of sclerites ­ e.g., the folding of palp segments described by K. Viets (1936) ­ is surely an artifact. Generally large dimensions (e.g., genital field L/W 850/950, chelicera L 2000) and the presence of at least 4 setae on Cx­4 clearly indicate that the specimen has close relationships to the geographica ­species group. The frontal sclerites, not clearly reported in the original description, consist of one pair of rod­shaped muscle attachments located medially from the postocularia. They are similar in shape to those of H. geographica , but shorter. They could have changed in shape and extension as a consequence of treatment during preparation. Also, the shape of the male gonopore (anteriorly extended and pointed) is in agreement with H. geographica , but in view of the bad conservation of the only available holotype specimen, it is best regarded as a species incerta .