[Fauna of monogeneans (Monogenea, Platyhelminthes) of gudgeons (Gobioninae, Cyprinidae). 1. Composition, structure, and characteristics of distribution].

Monogeneans parasitize 31 gudgeon species of 130, and 13 gudgeon genera of 30 known. Monogenea from gudgeon comprise 48 species of the genus Dactylogyrus, 1 Bivaginogyrus (Dactylogyridae), 18 Ancyrocephalus s. l. (Ancyrocephalidae), 6 Gyrodactylus (Gyrodactylidae), 3 Paradiplozoon, and 1 species of the genus Sindiplozoon (Diplozoidae). The following characters were used in the morphological analysis: (1) structure of the copulatory organ, (2) morphology of the anchors, marginal hooks and bars, (3) characteristic of attachment on gills. Among the Dactylogyrus species parasitizing gudgeon, 30 monophyletic species groups and 13 levels of morphological organization were established. The first level comprises dactylogyrids without the additional ventral bar of haptor. It includes species with the copulatory organ of pro-cryptomeres type. This type is ancestral for dactylogyrids of the Amur/China fauna. Levels II-IV; VI, etc. are derivates of level I. Levels VII-VIII can be characterized by the jamming type of attachment characteristic for Dactylogyrus sphyrna or D. anchoratus, when marginal hooks penetrate gill filaments towards the anchors. Levels IX-XII include species with the attachment by clasping, when the anchors directed towards each other. Some species groups of Dactylogyrus (V, XIII) switched onto gudgeons from other fishes (Cultrinae, Xenocyprininae, Hypophthalmichthinae). Species of the genus Ancyrocephalus s. l. form two levels of morphological organization and 8 monophyletic groups. Repeated switches of ancyrocephalids from freshwater gobies to gudgeons and their switches from gudgeons to other fishes were shown. Species of the genus Hemibarbus serve as hosts for morphologically peculiar species groups of Dactylogyrus and Ancyrocephalus s. l. We can conclude that gyrodactylids from gudgeons do not form a natural monophyletic group. This parasite fauna originated as a result of multiple switches from phylogenetically distant but ecologically similar hosts, for example sticklebacks, bitterlings, chars, spined loaches, etc. Species of the family Diplozoidae parasitizing gudgeons may invade also many species from other fish taxa.