New water mites of the family Hygrobatidae (Acari, Hydrachnidia) from Turkey

Abstract In this study, the findings of three water mite species of the family Hygrobatidae collected from different streams in Turkey were evaluated. Hygrobates (s. str.) anatolicus Esen & Pešić, sp. n. is described as new for science. Hygrobates (Rivobates) diversiporus Sokolow, 1927 and Atractides (s. str.) nikooae Pešić, 2004, which were illustrated and thoroughly discussed, are new records for the Turkish fauna.

During a survey of the freshwater fauna of Kahramanmaraş, Malatya and Siirt Provinces, Turkey, three interesting species for the Turkish fauna were collected. This article aims to describe this material and contribute to our knowledge of water mites distribution in Turkey.

Material and methods
During fieldwork, water mites were collected by hand netting, sorted on the spot from the living material, conserved in Koenike's fluid and dissected as described elsewhere (e.g., Gerecke et al. 2007). The holotype and some paratypes of the new species are deposited in the research collection of the Department of Biology, Fırat University, Elazığ, Turkey, other paratypes are deposited in the Museum of Natural History of Montenegro, Podgorica, Montenegro.
Male (  Discussion. Due to the shape of palp with a straight ventral margin of P-2, distally forming a right angle, the new species closely resembles Hygrobates (s. str.) nigromaculatus Lebert, 1879 ( Fig. 2D-E, G-H) and H. setosus Besseling, 1942. The later species, for a long time was considered a morphotype of H. nigromaculatus (Viets 1960), but differs in size (median length of Cx-I + gnathosoma > 350 µm. Males: P-4 length > 140, genital plate length > 170 µm. Females: P-4 length > 165, genital plate length > 175 µm), life cycle with larvae parasitic on chironomid Diptera and habitat preference for running waters (Martin et al. 2010). The larger dimensions and habitat preference for running waters makes the new species close to H. setosus. However, presence of lineated integument will easily distinguished Hygrobates anatolicus sp. n. from two above-mentioned species bearing finely striated integument.
Remarks. Due to the shape of the genital field, population from Göksu stream resembles populations of Hygrobates nigromaculatus and H. setosus from the Northern Germany (P. Martin pers. communication). However, population of H. nigromaculatus from the Ohrid Lake clearly differs in the shape of genital field (see Figs 2D-E), with the acetabula distinctly elongated, similar to those in H. longiporus Thor, 1898. The similar, longiporus-shape of the acetabula was recently detected in the population of H. nigromaculatus from Luxembourg (R. Gerecke pers. communication), suggesting that this character, in the H. nigromaculatus like-species complex, vary and can not be used in taxonomical separation. If possible the species should be included in a possibly molecular and morphological revision of the H. nigromaculatus like-species complex.
Etymology. Named after the country of the type locality.

Habitat. Rhithrobiont.
Distribution. Known only from the type locality in Kahramanmaraş Province, Turkey.

Subgenus Rivobates Thor, 1897
Hygrobates ( Rezazeh, 29.9.1974, Schwoerbel. Morphology. General characters. Posteromedial margin of Cx-I convexly rounded, medial margin of Cx-IV rounded; genital field with 8-13 pairs of acetabula. Ventral margin P-2 proximally concave, distally protruding in a nose-or knob-shaped projection bearing denticles, distal part of P-3 ventral margin covered by denticles, P-4 ventral setae distance 14-19 µm. Remarks. Sokolow (1927) described Hygrobates diversiporus based on one male and one female specimen from a first order stream in Caucasus. Later on this species has been reported by Bader (1955) from the Ohrid Lake in Macedonia. The latter record of this probably rithrobiontic species from a lacustrine habitat, require confirmation for a better under standing of its geographical distribution. The specimens from Turkey agree well with the type specimen in the shape of male genital field orginally desribed by Sokolow (1927) in German as reverse heart-shaped ("verkehrtherzförmig"), with an acute anterior angle and a indented posterior margin having a broad, rounded median notch.
The second member of subgenus Rivobates Thor known from Turkey, Hygrobates quanaticola Schwoerbel & Sepasgozarian, 1976, has been orginally described from Iran (Schwoerbel and Sepasgozarian 1976), and later on reported from Kayseri, Elazığ and Afyon provinces in Turkey (Erman et al. 2010). This species differs (based on re-examination of the holotype) from H. diversiporus in the shape of male genital field with irregularly convex posterior margin (compare Figures 3B-D and 4).