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.