[Characteristic features of the ranks genus and subgenus, and an intercalary rank "species complex" in ixodid ticks (Acari: Ixodidae)].

The work was carries our from the standpoint of the morphological conception of species. Vast collections of the Zoological Institute of the Russian Academy of Science testify to the existence of hiatuses in both genera and subgenera of Palearctic ixodids at all active phases of their ontogenesis. The fact that the subgenera of Palearctic genera have been well studies is notes, and composition of the subgenera is presented. The question of a taxonomic intercalary rank "species complex" is considered in detail in the context of the coevolution between some complexes of closely related species of ixodid ticks and some closely related species (genospecies, strains) of pathogens. The question of the taxonomic rank "species complex" in ixodid ticks as a phyletic species association is postulated on the basis of comparative ontogenetic data. Nomenclature status of the intercalary association "species complex" is specified in conformity with the fourth edition of the International Code of Zoological Nomenclature. Species composition of most studied complexes is presented. Some variants of morphological differentiation between species complexes within subgenus are considered. Significance of the taxonomic concept "species complex" for zoological. parasitological, and medical aspects of the ixodid ticks study was evaluated. Prognostic significance of the rank "species complex" for the study of the relationships between ixodid ticks and pathogens is discussed.