[Variability of the hard dorsal idiosomal tegument pattern and other phenotypic characters as a manifestation of microevolution in Dermacentor marginatus (Acari: Ixodidae)]

The pattern of male conscutum and female scutum in Dermacentor marginatus has been examined in 6 points of the East-European and Asian parts of its range (Fig. 1). A high rate of modification variability of the pattern has been recovered in each geographical sample. It is shown that populations differ reliably from each other by the length of the dark patches on the marginal flank of the conscutum (nkappabeta, npkappabeta, 3kappabeta); some samples also differ by the number of these patches, complexes of other patches of the scutum and conscutum, and as well (visually) by the color density of light fields and contrast between them and the dark background on the conscutum and scutum (Table 1, 2). Besides, the samples differ reliably at each stage by the complexes of morphometric characters (Table 3, 4). The sample from the Peter the First Ridge is most deviate from others by the color contrast and complex of patches both in males and females. However, by the patches of marginal flank and morphometric characters of both sexes and perimaginal stages this sample differ less from others. The sample from the Stavropol plateau having most variable pattern (Fig. 3, 1-9, 4, 1-3) is characterized by the greater number of statistically reliable differences by the patches (nkappabeta, npkappabeta, 3kappabeta) and morphometric characters of all stages of the ontogenesis from all other samples. Other geographical samples have intermedial position in regard to degree of differences from each other. The samples examined are considered as morphotypes; degree of differences between morphotypes is unequal. The phenotypic differences have mosaic dispersion among ontogenetic stages and do not show a coherent direction in comparing the morphotypes. Differential characters of the morphotypes and related tick species belong to different structures or their different parameters. Possible ways of morphotype's origin and geochronological characteristics of morphotypes are discussed.

[Prototypes of Hyalomma scupense Schulze, 1918 and H. detritum Schulze, 1919 (Acari: Ixodidae) in connection with microevolution within the genus]

Type series of two species of the genus Hyalomma Koch, 1844 deposited in the Museum of Zoology in Berlin have been examined. Examination of the H. detritum Schulze, 1919 holotype has shown that this name is actually a junior synonym (syn. nov.) of H. marginatum turanicum Pomerantsev, 1946. At the same time it was also found out that the paratypes of H. detritum are conspecific to the syntypes of H. scupense Schulze, 1818, among which the lectotype has been designated. Taxonomic errors of Schulze and other authors, which had led to a worldwide use in acorological literature the name H. detritum instead of the valid name H. scupense, are discussed. It is suggested that the reasons of microevolution within the polymorphic species H. scupense could be explained by unequal climatic conditions. Microevolutionary process in this species is most well expressed in a tendency to reduce the number of contacts with a host during the life cycle. It has resulted in the reformation of the two-host cycle into the one-host cycle.

[Effect of medications and acupuncture on indicators of a bioenergetigram of bronchial asthma patients]

AIM

To evaluate the energy informational effects of various treatments in patients with bronchial asthma (BA).

MATERIAL AND METHODS

Changes in bioenergograms were analyzed in 139 patients after therapeutical exposures: intravenous prednizolone and dexamethasone, inhaled seretide, fluthicasone propionate, beclomethasone, phenoterol, salmeterol, and salbutamol, the latter drug as tablets, as well as a course treatment with acupuncture. The energy informational effects of pumpan and nitrosorbide were studied in 22 patients with BA concurrent with cor pulmonale and coronary heart disease (CHD).

RESULTS

A significant difference was found in the parameters of a bioenergogram depending on the routes of administrations of the drugs and their dosage forms. The greatest and positive changes in the area of the bioenergogram were recorded when using salmeterol and salbutamol, particularly in the nebulization of their solutions, and acupuncture. The intravenous infusion of glucocorticosteroids frequently produced inhibitory effects. In patients with BA concurrent with cor pulmonale and CHD, the positive energy informational effect of pumpan, that differed from that of nitrosorbide, occurred with better ventricular repolarization and alleviated signs of right cardiac overload on ECG.

CONCLUSION

The bioenergogram is highly sensitive to changes in the status of patients and it may be used to choose drugs and their combinations, combined drug therapy, and acupuncture on an individual basis. Pumpan is recommended for the treatment of patients with BA concurrent with cor pulmonale.

[Morphological barrier in mechanisms of reproductive isolation acting in areas of sympatry of closely related species Ixodes persulcatus-I.pavlovskyi and I. persulcatus-I. ricinus (Ixodidae)]

A morphometric analysis of different male and female organs used in the process of copulation, including an attachment of the spermatophore to the genital opening of female and placing the spermatophore into the vestibular part of vagina, was carried out for the pairs of ixodid tick species Ixodes persulcatus--I. pavlovskyi and I. persulcatus--I. ricinus in areas of their sympatry. In two disjunctive areas of sympatry of I. persulcatus--I. pavlovskyi (South-East Altai and Southern Primorye), the morphological barrier is displayed in the precopulation mechanism of reproductive isolation and does act only in the pair I. pavlovskyi female--I. persulcatus male. It is proved by the reliable prevalence of the hypostome diameter (in widest part) of I. persulcatus male over the genital opening length of I. pavlovkyi female. Because of this reason, the copulation between these partners cannot take place. On the other hand, there are no any morphological obstacles for a copulation within each species examined and in the combination I. persulcatus female--I. pavlovskyi male, and in any combination of the partners I. persulcatus--I. ricinus in sympatry areas (samples from two locations in the north-west of the Eastern-European Plane have been examined). Morphological peculiarities causing differences in host preference of tick species, that in turn realizes the isolation mechanisms between species, are discussed. Postcopulation non-genetic components of the reproductive isolation mechanism have been found in examined species.

[Multistage mechanism of reproductive sympatric isolation of the closely-related species, Ixodes persulcatus and I. Pavloskyi (Ixodidae)]

The closely related species Ixodes persulcatus and I. pavlovskyi are vectors of agents tick-born encephalitis and Lyme disease. These species have two great disjunctive sympatric distribution areas (fig. 1), where both species inhabit the same biotopes, and during the same season. In these conditions there are prerequisites of contacts of opposite sexes of the different species during ambushing the hosts on vegetation. Sequence of "switching on" of the morphological, physiological, and hostparasite factors of reproductive isolation has been established. The features and the range of manifestation of these factors at different combinations of sexes and species of the partners have been revealed. The studied factors, such as precopulative and postcopulative components of the mechanism of reproductive isolation of I. persulcatus and I. pavlovskyi were considered. A hypothesis for sympatric origin of the species as a result of specialization the adults of I. persulcatus to mammals, and I. pavlovskyi to birds is proposed.

[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.

[The intraspecific taxonomic structure and identification of closely related species of ixodid ticks (Ixodidae)]

Two variants of intraspecific morphological differentiation of 7 palearctic species of Ixodidae and respectively two variants of their intraspecific taxonomic pattern have been revealed on the basis of the study of geographic variation of each species. Three species--Ixodes pavlovskyi Pom., 1946, Haemaphysalis erinacei Pavesi, 1884, Hyalomma asiaticum Sch. et Schl., 1929, are subdivided into subspecies, and four ones--I. ricinus (L., 1758), I. persulcatus Sch., 1930, I. crenulatus Koch, 1844, Dermacentor marginatus (Sulzer, 1776),--into morphotypes by the degree of distinction of the whole complex of active stages in ontogenesis. Acknowledging the conventional character of the categories of subspecies and morphotype their criteria have been formulated for ixodid ticks. Paleogeographic and ecological grounds are given. Some data of geographic variation of immature stages favour the identification of closely related species in concrete localities.

[The sympatry of closely related species of ixodid ticks and its possible role in the parasitic systems of natural foci of transmissible diseases]

Sympatry of the following pairs (or groups) of closely related species in the territory of the former Soviet Union amd some neighbouring countries has been revealed as a result of a revision of the fam. Ixodidae: I. persulcatus-I. ricinus, I. persulcatus-I. pavlovskyi, I. crenulatus-I. kaiseri, Dermacentor marginatus-D. silvarum-D. ushakovae, D. ushakovae-D. niveus, D. pavlovskyi-D. montanus, Rhipicephalus turanicus-R. sanguineus, R. turanicus-R. rossicus, R. turanicus-R. pumilio, R. rossicus-R. pumilio. Biotope and host relationships of sympatric species, as well as seasons of parasitizing have been described on the basis of the field researches conducted by the author, the collections of the Zoological Institute, Russian Academy of Sciences, and the publications substantiated by collection materials studied by the author. Hypothetic ways of the paleogenesis of each sympatric area and geological age have been considered. The recent sympatric area for I. persulcatus-I. ricinus (fig. 1) is of Holocene age (max. 8.000-10.000 years). During that period approximately 1600-2000 sympatric generations could have been realized. Some recent sympatric areas (I. persulcatus-I. pavlovskyi, and some species of other genera) are of Pleistocene and even Pliocene age (2-10 million years). In these areas the number of realized sympatric generations must have been much higher. Several variants of joint simultaneous and successive feeding on one and the same host individual have been established for stages of life cycles of sympatric species of ticks. Contacts of this kind could have created canals for multiple oscillatory exchange of pathogenic taxa (species, genospecies, strains) in a few or many thousands of sympatric generations of closely related vectors. Thus, the same taxon of a pathogen may be subject to different influence of ixodid vectors in sympatric area and in the area of separate habitat of close species of vectors.

[Desmoplastic malignant melanoma]

A rare case of desmoplastic malignant melanoma which produced many difficulties in diagnosis is reported. Analysis of histological structure of the primary tumor and its metastases as well as signs of melanocytic differentiation found at electron-microscopic level enabled differentiation of this tumor with neoplasms of another histogenesis which is important for treatment and prognosis.

Influence of exogenous RAR alpha gene on MDR1 expression and P-glycoprotein function in human and rodent cell lines

The goal of our study was to obtain direct evidence of co-ordinated regulation of P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) and differentiation in tumour cells and to study some signalling pathways involved in joint regulation of these two cell phenotypes. The sublines of human melanoma (mS) and hepatoma (human HepG2 and rat McA RH 7777) cell lines were obtained by retroviral infection of the wild-type cells with the cDNA of the human retinoic acid receptor alpha (RAR alpha). The resulting sublines stably overexpressed exogenous RAR alpha gene. The infectants became more differentiated than the parental cells as determined by a decrease in the synthesis of the embryo-specific alpha-fetoprotein in HepG2 and McA RH 7777 hepatoma cells and by an increase in melanin synthesis in mS cells. The differentiation of human cells was accompanied by an increase in the amounts of MDR1 mRNA but not by an increase in P-gp activity as a drug transporter, in contrast, in the rat RAR alpha overexpressing cells P-gp functional activity was elevated. Treatment with cytotoxic drug (colchicine) or retinoic acid (RA) resulted in a slight increase in P-gp activity in the parental and RAR alpha-infected melanoma cells, whereas the increase in P-gp function in the infected hepatoma cells (both human and rat) was very prominent. Thus, we provide new evidence that cell differentiation caused by the overexpression of the gene participating in the differentiation programme leads to overexpression of MDR1 gene and drug resistance and that this effect is tissue and species specific. These data imply that the activation of the RA-controlled signalling pathway up-regulates MDR1 gene expression.

Relationships between species of the Rhipicephalus sanguineus group: a molecular approach

The biosystematic status of species belonging to the Rhipicephalus sanguineus group is difficult to determine by phenotypic methods and has been subject to frequent revisions and ongoing debate. Yet, the differentiation of species within this complex is of clinical importance especially in veterinary medicine due to different host specificities of the transmitted pathogens. In order to generate quantifiable and comparable data independent of environmental influences, a section of the second internal transcribed spacer (ITS2) of the rRNA gene was sequenced for 6 species belonging to the Rhipicephalus sanguineus complex: Rhipicephalus sanguineus sensu stricto, R. turanicus, R. rossicus, R. pumilio, R. pusillus, and R. camicasi. Rhipicephalus sanguineus s. str. and R. turanicus as well as R. pumilio and R. rossicus were found to have a close genetic relationship compatible with possible conspecificities. Conversely, R. pusillus was found to have the most distant relationship to the other species.

[Geographic variability in the sexually mature phase of Ixodes persulcatus (Ixodidae). Experience in using databases on morphometry]

The aim of the article is to estimate geographic variation of Ixodes persulcatus adults as a whole. Intraspecific variation of the females and males of Ixodes persulcatus Schulze, 1930 has been studied in eight geographical localities ("populations") of its distribution range (fig. 1.). The distance between western and eastern localities is more than 8700 km, between northern and southern ones it is approximately 2900 km. Twenty five to thirty specimens of each sex were studied in each geographical locality. The following eleven characters were used (fig. 2, 3): length of scutum (conscutum), width of scutum (conscutum), length of anal ring, width of anal ring, length of spiracular plate, width of spiracular plate, length of gnathosoma, width of gnathosoma, length of II-III articles of palps, length of hypostome, length of tarsus 1. The multidimensional scaling method by means of software package SYSTAT was used for estimation of relationships between populations on the basis of morphometrical data. The differences between the populations were revealed only from absolute sizes of organs, whereas their proportions (i. e. shape) were constant in all geographical localities. Fig. 4, 1 shows that females from localities G (Primorski Territory) and C (Tien Shan Mountains) occupy extreme positions. Fig. 4, 2 shows that males from localities G (Primorski Territory) and D (SW Altai Mountains) on the one hand and A, B (European) on the other one occupy extreme positions. Locality C (Tien Shan Mountains) is similar to F (Western Sayan Mountains) and to European (A, B) whereas females of locality C differ from A, B and F. Taking into account the partial discrepancy of relationships between populations in sexes we have united the data on corresponding characters of both sexes in the aggregate data base (fig. 4, 3). This was possible owing to the multidimensional scaling method. Fig. 4, 3 shows isolated position of the population G (Primorski Territory), specimens of which are the largest in sizes. The populations D (SW Altai Mountains) and H (Sakhalin Island) are morphometrically most similar to the population G. The population C (Tien-Shan Mountains) is represented of the smallest specimens. The European populations (A and B) are closer to C. The largest sizes are typical of the populations G and D associated with relict Tertiary landscapes of Primorski Territory and SW Altai with which areas of ecological optimum of I. persulcatus coincide. The smallest sizes are observed in the European populations (A, B) near the north-western boundary of the distribution range of the species, as well as in the Alpine population of Tien-Shan Mountains, near the upper vertical boundary of the distribution range (2000-3000 m above sea level). Climatic conditions of the habitat in these areas are similar to those of the northwestern part of the distribution range of I. persulcatus.

Alterations of melanin synthesis in human melanoma cells selected in vitro for multidrug resistance

Previous data showing the correlation of multidrug resistance (MDR) and differentiation in tumor cell populations (Melloni et al. 1988; Stavrovskaya et al. 1990) suggest that: 1) isolation of MDR cells by cytostatic drugs leads to the selection of more differentiated cell variants and 2) in more differentiated cell variants the activity of MDR-related P-glycoprotein (Pgp) is more prominent than in less differentiated cells. Here we used human melanoma cell line mS and two variants selected from mS population: a) MDR variant of mS selected by colchicine (mS-0.5) and b) mS-trRAR/2--variant obtained by introduction of expressing retinoic acid receptor RAR-alpha cDNA into mS cell. The differentiation status, expression of MDR1 gene and Pgp functioning were compared in wild-type cells and mS variants. Electron microscopic examination of melanosomes showed that the mS-0.5 subline comprised more differentiating cells in the population than parental mS cultures and that these cells were at later stages of melanogenesis. The increase in the degree of differentiation in mS-0.5 population coincided with MDR1 gene overexpression, occurrence of Pgp molecules on the cell membrane and acceleration of Pgp-mediated Rhodamine 123 (Rh123) efflux. mS-trRAR/2, proved to be more differentiated than mS cells. The MDR1 mRNA level and Rh123 efflux were not elevated in mS-trRAR/2 cells, however, retinoic acid (RA) treatment increased both the degree of differentiation and Rh123 efflux in mS-trRAR/2 to a greater extent than in mS cultures. Thus, the data obtained in this study are in favor of the suppositions mentioned above. The mechanisms of coordinated alterations of differentiation and Pgp activity in MDR cells are discussed.

[Characteristics of the effects of artificial alkalosis on electrical activity of the brain and ultrastructure of blood cells in oncologic patients]

The authors examined 40 patients with malignant tumors of various histogenesis, sites and extent, as well as 5 patients with benign tumors and other non-tumorous diseases. They also studied their electroencephalography and peripheral blood lymphocytic and erythrocytic ultrastructure in metabolic alkalosis temporarily induced by intravenous sodium hydrogen carbonate. In cancer patients without late metastases, alkalosis caused a transient normalization of previously altered electroencephalography, erythrocyte disaggregation and substantially reduced the count of killer cells in small and middle lymphocytes. These findings suggest that patients with malignant neoplasms have a generalized intracellular acidosis which can be temporarily abolished by plasma alkalinization.

[The taxonomic aspects of the transmission of the causative agent of Lyme disease]

According to world literature data 17 species of ixodid ticks have been studied for natural infection with the Lyme disease agent. Analysis of the data on the level of the infection, transovarial and transphase transmission has shown that main biological vectors of Borrelia burgdorferi are the species of the subgenus Ixodes s. str. - I. ricinus, I. persulcatus (Eurasia), I. dammini, I. pacificus (North America). Potential vectors are I. scapularis, I. dentatus, Amblyomma americanum, Dermacentor variabilis. Single isolations were registered for I. neotomae, Haemaphysalis leporispalustris, D. occidentalis. Nonidentified spirocheta was isolated from A. americanum, D. variabilis, D. parumapertum, Rhipicephalus sanguineus. No agent was isolated from I. cookey, D. albipictus, R. reticulatus, H. concinna. On the basis of comparative and ontogenetic data the species from a group of main vectors: I. ricinus, I. persulcatus, I. pacificus had been attributed by me to the phyletic group persulcatus before Lyme disease was discovered and its causative agent isolated. The question whether I. scapularis belongs to the group persulcatus was also discussed at that time but left open due to somewhat aberrant structure of gnathosoma at preimaginal phases (Filippova, 1969, 1971, 1973). 6 Palaearctic, 2 Indomalayan and 3 Nearctic species were referred to the group persulcatus at the time. I. dammini was described later, in 1979. Gnathosoma of its preimaginal phases has an intermediate structure between I. scapularis and other species of the group persulcatus. Sexually mature phase and nymph of I. dentatus have much in common with Palaearctic members of the group, I. pavlovskyi, I. kazakstani, I. kashmicus. Preimaginal phases of I. scapularis and nymph of I. dentatus were studied by me on the collection material. Thus, it is possible to speak of the belonging of main vectors of B. burgdorferi to a common phyletic group within the subgenus Ixodes s. str. and, therefore, of common origin of ecological medium for the agent. At the same time each species of the vector is an evolutionally developed difference of ecological medium for B. burgdorferi. Roots of the group persulcatus could originate as far as in Paleocene before the land connection between North America and Europe disappeared. Conditions for the existence of recent species, however, appeared considerably later and their flourishing is dated by Pliocene. The main epidemiological role belongs now to I. ricinus, I. persulcatus, I. dammini, I. pacificus.(ABSTRACT TRUNCATED AT 400 WORDS)

[A description of the female and larva of the relic species Ixodes ghilarovi (Ixodidae)]

Ixodes (Exopalpiger) ghilarovi was found in 4 separated localities of the Great Caucasus at a height of 1000 to 2200 m above sea level. Female differs from palaearctic I. (Exopalpiger) trianguliceps in 4-4 pairs of setae of the anal valve, shape of scutum, longer setae of alloscutum, more round peritreme, correlation between the length of peritreme longitudinal diameter and the length of longitudinal diameter of the anal ring, presence of auricles and shape of palps. Larva differs from I. trianguliceps in longer setae of alloscutum, longer ventrolateral tooth of 1st palpal joint and longer medial tooth of coxae I.

[Diagnosis of species by the larval phase in the genus Rhipicephalus Koch (Ixodidae) in USSR fauna]

The key for identification of species of the genus Rhipicephalus (the fauna of the USSR) on the larval phase is based on the material reared under laboratory conditions. The structure of scutum, organs of gnathosoma and coxae, chaetotaxy of idiosoma and gnathosoma were used for differential diagnosis. In addition morphometric characteristics of the above structures and their proportions were used. A special attention has been given to coexistence of species in sympatric zones, which was revealed or confirmed as a result of identification of species of the genus on larva in the ranges of the fauna of the USSR.

[Evaluation of the apron as a taxonomic trait in ixodid ticks of the genus Dermacentor Koch (Ixodoidea, Ixodidae)]

Study of the apron in 9 species of the genus Dermacentor from the fauna of the USSR has revealed differencies in its structure. The subgenus Dermacentor (s. str.) differs from two other subgenera both in the shape of the apron itself and in the shape of the postgenital sclerite and setae of perigenital area. Close species within each of two other subgenera differ in apron proportion, shape and size of denticles along its hind edge, and sometimes in their number. Inspite of the statistically reliable interspecific differences in apron structure a wide range of individual variability of some details and geographical specificity of samples from various places of the area were observed in species with a vast area.

[Diagnosis of subgenera of the genus Dermacentor Koch by the larva and nymph and new data on the distribution of the subgenus Asiacentor (Ixodidae)]

On the basis of parallel study of natural and cultivated preimaginal phases of the genus Dermacentor differential diagnoses of three palaearctic subgenera were worked out: Asiacentor Filippova et Panova , 1974, Serdjukovia Dias , 1963 and Dermacentor (s. str.) 1844. The diagnoses are also based on peculiarities of chaetotaxy and other characters of small sizes. On the basis of identification of species of the subgenus Asiacentor on immature phases new sites of their distribution were found out: D. pavlovskyi : in the Issyk - Kul hollow, in the foothills from the side of Terskey - Alatau ridge; D. montanus: in Gissarsky ridge in the environs of Lake Iskander - Kul . Remoteness of these cites from the distribution borders known earlier point to ecological and geografical differential peculiarities of the subgenus and its species.

[Redescription of Dermacentor raskemensis Pomerantzev, 1946 (Ixodidae)--a representative of the mountain fauna of the southern regions of the USSR and adjacent territories]

A redescription of female and male of the little-known species Dermacentor raskemensis Pomerantzev has been made on the holotype (male, West China, Sinkiang) and on collection material of Zoological Institute of the Academy of Sciences of the USSR and Institute of Zoology of Armenian SSR: three females and males from Armenia and western Pakistan. Despite a considerable remoteness of their distribution areas all studied specimens show stability of their specific characters and differ distinctly from the close species D. niveus Neumann and D. everestianus Hirst. The both sexes (especially female) of D. raskemensis differ in having peculiar, most complete (in the ranges of the genus) filing of the dorsal shield area with dense light pigment and by prevalence of very small punctation and the lack of contrast between it and larger punctation. Peritreme of D. raskemensis male has a long narrow dorsal process which is at the right angel to its longitudinal axis and slightly concave along the hind edge. The dorsal process of the female is well developed and is at the right or acute angles to the longitudinal axis. In addition the both sexes have a wide smooth thickening along the anterior edge of the process, the proportions of peritreme are specific in species. In close species the dorsal process of peritreme is at the blunt angle to its longitudinal axis, in D. everestianus the thickening along the anterior edge is missing. Female of D. raskemensis lacks wing-shaped appendages of the genital opening while in D. niveus they are distinct (the structure is not mentioned in the description of D everestianus). D. raskenmensis apparently inhabits highlands and meadow-steppe, steppe and mountain sparce forest zones most part of which is covered by rocks and screes. In Armenia it was recorded from Armenian mouflon and wild goat; in other countries (Iran, Afghanistan, western Pakistan, India and China) it occurs on sheep and goats from alpine pastures. Most collections were done in autumn, winter and spring.