[The intraspecific differentiation of the burrow tick Ixodes crenulatus (Ixodidae)]

In four extensive disjunct areas of the distribution range of Ixodes crenulatus Koch, 1844 complexes of samples in 8 locations, and separate samples in two locations have been studied (fig.). Morphological characters (sizes of organs of idiosome, gnathostoma, legs, as well as some proportions of organs), which show statistically significant differences between complexes of samples on all corresponding stages of ontogenesis were revealed (tabl. 1, 2). Statistically significant differences were determined by Student's criterion (table. 3, 4). We use the term "transit" characters to denote these characters if they have to addition a similar tendency at all stages of ontogenesis. Complexes of samples showing statistically significant differences of transit characters are considered by us as morphotypes. Apparently these differences of morphotypes were formed evolutionally. In European disjunct area morphotypes divided into two groups on the basis of the degree of differences: western (A, B), and eastern (C, D, E). Degree of differences of morphotypes within each group is low, whereas one between of these two groups is high and corresponds to differences of morphotypes A, B from all Asian morphotypes (F, G, H, I, J), and of morphotypes C, D, E from Asian ones in mountain disjunct areas I. crenulatus (G, H, I, J). At the same time Eastern-European complex of morphotypes (C, D, E) is morphologically similar to the morphotype from north Kazakhstan disjunct area (F). All Asian morphotypes have high degree of differences one from the other. Species of the genus Marmota are initial hosts of I. crenulatus, they retain the main role as hosts in Eastern-European and Asian morphotypes: C, D, E, F--M. bobac bobac (Muller, 1776), G--M. baibacina centralis (Thomas, 1909), I, J--M. sibirica sibirica (Radde, 1862). The most aberrant in all characters morphotypes are the ones inhabiting European areas (A, B), where marmots are exterminated. These morphotypes parasitize on hibernating carnivores.