The European species of the genus Lebertia Neuman, 1880 are revised based on a study of available types and additional material from museum collections and recent field work, mostly done in the southern part of the continent. The taxonomic significance of all morphological character states considered as diagnostic by former authors is reevaluated in light of a detailed analysis of the variability of these characters in L. fimbriata. The subgenus Mixolebertia is redefined, the subgenus Pseudolebertia is synonymized with Lebertia sensu strictu. The synonymy of Hexalebertia with Mixolebertia, proposed by previous authors but not generally accepted is confirmed. Eolebertia nov. subgen. is proposed in order to accommodate L. elsteri and a species new to science. Descriptions and diagnoses are provided for all recognized species. Neotypes are designated for two species (L. fimbriata and L. brevipora) and lectotypes for 16 species (L. apposita, L. bracteata, L. bisbisetosa, L. crenophila, L. dalmatica, L. hispanica, L. holsatica, L. jadrensis, L. longipalpis, L maculosa, L. purpurea, L. rivulorum, L. schechteli, L. semireticulata, L. silesiaca and L. subtilis). Four subspecies are elevated to species rank (with their former stem species in parentheses): L. reticulata Koenike, 1912 (rufipes); L. rubella K. Viets, 1926 (tuberosa); L. excellens Lundblad, 1956a (tenuicollis); L. nitida Motaş & Tanasachi, 1963 (holsatica). Due to insufficient documentation, 21 taxa are considered as species incertae: L. tauinsignita (Lebert, 1879); L. longipes Monti, 1904; L. walteri Thor, 1906; L. costata Koenike, 1908; L. sigthori Maglio, 1908; L. duricoria Koenike, 1911; L. saxonica Thor, 1911; L. inflexa Thor, 1913; L. gladiator Thor, 1913; L. multicincta Thor, 1914; L. komareki Thor, 1914; L. schechteli globifera Thor, 1914; L. lacustris Koenike, 1914; L. aspera Walter, 1922; L. incognita K. Viets, 1922; L. pulchella K. Viets, 1925; L. monardi Migot, 1926; L. pyrenaica Migot, 1926; L. dresdensis K. Viets, 1928; L. elliptica Husiatinschi, 1937and L. cylindrata Bader, 1955. The following synonymies proposed by former authors are rejected: L. aberrata K. Viets, 1922 = L. cuneifera Walter, 1922: Schwoerbel 1955a (separate species) L. algeriensis Lundblad, 1942 = L. inaequalis: Besseling 1956 (separate species) L. contracta Thor, 1900 = L. densa (?): K. Viets & K. O. Viets 1960 (separate species) L. cylindrata Bader, 1955 = L. semireticulata K. Viets, 1925: Lundblad 1956a (species incerta) L. giardinai Maglio, 1908 = L. robusta Walter, 1922: Bader 1975 (priority; L. robusta = L. fontana) L. maculosa Koenike, 1902 = L. zschokkei Koenike, 1902: Lundblad 1962 (priority; vice versa) L. pallida Láska, 1954 = L. sparsicapillata Thor, 1905: Láska 1963 (= L. pusilla) L. stigmatifera separata Lundblad, 1930 = L. stigmatifera: Lundblad 1962 (separate species) L. zachariasi Koenike, 1912 = L. rufipes Koenike, 1902: Bader 1975 (= L. reticulata). The following 42 new synonyms are proposed: L. acuta minor Láska, 1954 = L. maglioi Thor, 1907 L. affinis Sokolow, 1927 = L. fimbriata Thor, 1899 L. apposita Láska, 1954 = L. maglioi Thor, 1907 L. arndti K. Viets, 1926 = L. maculosa Koenike, 1902 L. balcarica Sokolow, 1940a (err.: balcaria K. O. Viets 1987) = L. maglioi Thor, 1907 L. barsica Szalay, 1937 = L. haliki K. Viets, 1928 L. berlesei Thor, 1926 = L. oudemansi Koenike, 1898 L. caucasica cubanica Sokolow, 1940a = L. porosa Thor, 1900 L. corsica E. Angelier, 1954 = L. sparsicapillata Thor, 1905 L. rufipes cylindrica Láska, 1952 = L. sparsicapillata Thor, 1905 L. densa Koenike, 1902 = L. dubia Thor, 1899 L. dubiaeformis Sokolow, 1930 = L. helvetica Thor, 1906 L. extendens Walter, 1922 = L. fontana Walter, 1912 L. gracilipes Walter, 1922 = L. giardinai Maglio, 1908 L. husmanni K. Viets, 1955 = L. maglioi Thor, 1907 L. inversa Koenike, 1919 = L. cognata Koenike, 1902 L. longiepimerata Láska, 1953 = L. sparsicapillata Thor, 1905 L. multipilosa Thor, 1926 = L. natans K. Viets, 1926 L. neocomensis Bader, 1955 = L. longiseta Bader, 1955 L. obesa K. Viets, 1925 = L. cognata Koenike, 1902 L. olonensis Sokolow, 1930 = L. pusilla Koenike, 1911 L. pallida Láska, 1954 = L. pusilla Koenike, 1911 L. pseudotuberosa Bader, 1975 = L. maculosa Koenike, 1902 L. quadripora Koenike, 1903 = L. inaequalis Koch, 1837 L. robusta Walter, 1922 = L. fontana Walter, 1912 L. rufipes cylindrica Láska, 1952 = L. sparsicapillata Thor, 1905 L. schischkoffi K. Viets, 1926 = L. maculosa Koenike, 1902 L. schmidtii Thor, 1911 = L. halberti Koenike, 1902 L. scutellata K. O. Viets, 1955 = L. maglioi Thor, 1907 L. sefveoides Schwoerbel, 1962 = L. giardinai Maglio, 1908 L. shadini Sokolow, 1940 (“L. subtilis var.” Sokolow, 1925) = L. oblonga Koenike, 1911 L. silesiaca Láska, 1955 = L. pusilla Koenike, 1911 L. slovenica Láska, 1954 = L. rufipes Koenike, 1902 L. stackelbergi saxicola Sokolow, 1936 = L. porosa Thor, 1900 L. sublitoralis Walter, 1922 = L. oblonga Koenike, 1911 L. tenuistriata K. Viets, 1936 = L. fimbriata Thor, 1899 L. tuberosa Thor, 1914 = L. schechteli Thor, 1913 L. wackeri Bader, 1955 = L. inaequalis Koch, 1837 L. westfalica Koenike, 1919 = L. sparsicapillata Thor, 1905 L. zachariasi Koenike, 1912 = L. reticulata Koenike, 1919 L. zermattensis Walter, 1922 = L. maculosa Koenike, 1902 L. zschokkei Koenike, 1902 = L. maculosa Koenike, 1902 For seven species previously known only from specimens of one sex, the corresponding male or female is described for the first time: L. bulgariensis (♀), L. excellens (♀), L. halberti (♀), L. macilenta (♂), L. natans (♂), L. oblonga (♀), L. semireticulata (♂). Nine species are described as new to science: Lebertia (s. str.) aroania from a spring in the Peloponnese; L. (s. str.) variolata from streams in Sicily and Cyprus; L. (s. str.) intronata from springs in the Central-Western Mediterranean area; L. (s. str.) vegacabrerae from a stream on Tenerife, L. (Mixolebertia) helocrenica from springs in the Italian Alps and Bavarian prealps; L. (Mixolebertia) oxa from springs and interstitial habitats in Sicily; L. (Mixolebertia) mediterranea from springs in the Mediterranean area; L. (Brentalebertia) hupalupu from a spring stream on Gomera, and L. (Eolebertia) danielei from lowland springs in N Italy. A dichotomous key is provided for all recognized European species.

Members of the water mite genus Lebertia are one of the most common and often abundant inhabitants of streams in Europe. However, identifying members of this genus was up to now an arduous job. The taxonomy of this genus has been a chaos for some 100 years. The Norwegian acarologist Sig Thor (1856-1937) made a large-scale revision of the genus, resulting in the description of many new Lebertia species. Unfortunately, for unknown reasons, he decided that his whole collection should be destroyed after his death. Many species were described in the 20th century, many of them poorly documented and not very well differentiated from previously described species. The taxonomic mess was exacerbated by the erroneous assumption that Lebertia species of springs were not parasitic and therefore had limited dispersion potential. Finally, no key was available for Europe.

With the publication of the revision by Reinhard Gerecke all these problems are now a thing of the past. The paper starts with a sound description of the morphology of the genus. A discussion of the variability of morphological characters is supported by a year-round study of the variability of the common and widespread Lebertia fimbriata. In a chapter on the zoogeography of the genus, Gerecke states that its distribution is Holarctic, with a few species found in the Oriental, Afrotropical and Neotropical (South America) regions. However, no species have been found in South America, although the genus occurs in Central America, which is a part of the Neotropics. Not discussed by the author is the fact that the majority of species in the Holarctic occurs in Europe, where three times as many species have been found compared to North America. The systematic part starts with a discussion of the family Lebertiidae and its relatives. Gerecke proposes to synonymize the Nearctic genus Estelloxus Habeeb with Lebertia. With regards to the subgenera, Gerecke synonymizes the subgenera Pseudolebertia Thor with Lebertia s.s. and Mixolebertia Thor with Hexalebertia Thor. A new subgenus, Eolebertia, is erected to accommodate one new and one existing species. The two known species from Madeira are placed in the subgenus Mixolebertia with a question mark. These two species represent a distinct evolutionary line, and merit placement in a subgenus of their own.

The main part of the publication deals with the description of the species. Gerecke gives a description of 73 ‘good’ species from Europe and, remarkably, one from Greenland. In total, 42 new synonyms are established, while 21 taxa are considered species incertae. If one considers that many synonyms have already been established in the past, one gets an idea of the taxonomic chaos. An example is L. porosa: Gerecke lists 28 old and new synonyms! Moreover, Gerecke describes nine species new to science and elevates four subspecies to species rank. A dichotomous key makes it possible to identifyevery European species. Unfortunately, the most common and widespread species ends up last in the key. For The Netherlands, Smit & Van der Hammen (2000) listed thirteen Lebertia species, and an additional species is published by Smit et al. (2003). Members of the genus are found mostly in springs and low order streams. Their occurrence in The Netherlands is therefore almost limited to the eastern and southern part of the country. The publication of Gerecke also affects the Dutch list of water mites. Lebertia obesa is now a synonym of L. cognata and Lebertia lineata is a synonym of L. glabra.

In a publication like this it is hard to avoid small errors. The cover often escapes the attention of authors and on the cover of this book there is a misspelling of the author of the genus name, which should be Neuman. On page 7, the author name of Estelloxus is given as Halbert, but this should be Habeeb.

The revision of the genus Lebertia must have been a sisyphean task. The taxonomic chaos has blocked the systematics of the genus for decades. Every limnologist working in streams and springs should buy this publication. Water mites are an important part of the ecosystem and cannot be neglected anymore.

Harry Smit

entomologische berichten 69 (6) 2009, p 238-239