S-ITS2 rDNA Sequences Research Articles

Identification of a new species of Gyrodactylus von Nordmann, 1832 (Monogenoidea Gyrodactylidae) isolated from Diptychus maculatus in Yarkand River, Xinjiang, China

To investigate Gyrodactylus infection of fish in the river system of Xinjiang (China), Gyrodactylus individuals were isolated from specimens of Diptychus maculatus. Morphological characterization and phylogenetic analysis based on ITS1-5.8S-ITS2 rDNA locus revealed that the gyrodactylids belong to new species. Gyrodactylus diptychi n. sp. differs significantly in the morphology of the haptoral structures from 12 known species of Gyrodactylus found in fishes of the subfamily Schizothoracinae. In particular, G. diptychi n. sp. has a relatively short dorsal bar with thick and large ends, flat and straight hamuli roots, and small ventral bar processes. Furthermore, G. diptychi n. sp. is the only representative of Gyrodactylus found on D. maculatus. Using the BLASTn search of ITS1-5.8S-ITS2 rDNA sequences in GenBank and the Bayesian Information and Maximum Likelihood methods, we constructed phylogenetic trees for G. diptychi n. sp. As a result, our studies clearly identified that G. diptychi n. sp. was the first Gyrodactylus monogenean isolated from D. maculatus and a new species belonged to the subgenus Limnonephrotus.

Characterization of three-nucleate Rhizoctonia AG-E based on their morphology and phylogeny

The genus Rhizoctonia has been classified into two main groups according to the number of nuclei. Binucleate Rhizoctonia strains have two nuclei in each cell, whereas multinucleate Rhizoctonia fungi were observed to have a variable number of nuclei ranging from 4 to 16 in each cell. In the study, twelve Polish isolates were tested. According to ITS1-5,8S-ITS2 rDNA sequences, the isolates were classified in the AG-E. Their affiliation to AG was confirmed by anastomosis reactions with tester isolates. The number of nuclei was counted with DAPI staining under a fluorescent microscope, and the diameter of the hyphae was also measured. Not all AG-E isolates had the same number of nuclei in their cells: one group among these fungi produced cells with a diverse number of nuclei, usually 3; however, this number ranged from 2 to 4, making the average number of nuclei close to 3. It can be assumed that all isolates with three nuclei belong to this group, which may greatly facilitate the preliminary identification of trinucleate isolates of Rhizoctonia spp. belonging to AG-E. Based on these characters, we call these isolates AG-E-3n isolates. The thiamine requirement is not helpful in classifying and describing the AG-E strains.

New species of Gyrodactylus von Nordmann, 1832 (Monogenoidea: Gyrodactylidae) from Gymnodiptychus dybowskii (Kessler, 1874) (Schizothoracinae) in the Kunes River (Yili River basin), China

Yili River system hosts a diverse fauna of fishes and parasites. Gymnodiptychus dybowskii is a rare and endangered aboriginal cold-water fish inhabit in the Yili river system. Our research identified a new species Gyrodactylus gymnodiptychi n. sp. isolated from G. dybowskii in the Kunes River (Yili River, China). Morphological comparison revealed identifiable differences between the new species and other parasites, including Gyrodactylus aksuensis, and Gyrodactylus tokobaevi, which are two known parasites living in G. dybowskii inhabit in the Aksu River west of Frunze (Kyrgyzstan), as well as Gyrodactylus montanus living in Shizothorax intermedius inhabited in the Tadzhikistan or Uzbekistan. Especially, the dorsal bar of G. gymnodiptychi n. sp. was raised at both ends with a hollow, and its hamulus roots were curved inward. The BLASTN search of GenBank did not detect any other ITS1-5.8S-ITS2 rDNA sequences same as G. gymnodiptychi's. Using the Bayesian Information and Maximum Likelihood methods to analyze the ITS1-5.8S-ITS2 rDNA gene sequences, we constructed phylogenetic trees for G. gymnodiptychi n. sp. Accordingly, our morphological and molecular research indicated that G. gymnodiptychi n. sp. was not only a new species of parasites but also the first Gyrodactylus member identified in the Yili River in China.

Thaxterogaster revisited: A phylogenetic and taxonomic overview of sequestrate Cortinarius from Patagonia

ABSTRACT In the Patagonian region, Cortinarius is the most diverse and abundant genus of ectomycorrhizal fungi with at least 250 species. Sequestrate forms were until recently documented within the genus Thaxterogaster, a genus now known to be polyphyletic, and many were consequently transferred to Cortinarius. Original descriptions were mostly available in German and Spanish and interpretations of morphological structures outdated. Despite recent advances in Cortinarius systematics, the current classification, diversity, and ecology of sequestrate “cortinarioid” fungi in Patagonia remain unclear. The objective of this study was to provide an update on sequestrate Cortinarius of southern South America. We documented each species with morphological descriptions, photographs, basidiospore scanning electron microscopy (SEM) images, and molecular characterization using nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS) and nuc 28S rDNA (28S) sequence data. Original descriptions of taxa were also translated to English and revised based on fresh collections. We documented 24 species from Patagonia based on molecular data and conducted morphological and phylogenetic analysis for 18 previously described species based on type and reference specimens. In addition, we formally described two new species. Four additional taxa were provisionally determined as new but require further study. New ITS sequence data were produced from eight type specimens. We also provide a new name, Cortinarius gloiodes, nom. nov., for the taxon previously described as Thaxterogaster gliocyclus. In addition to the species treated in detail, we provided additional reference information and discussion on six described species that remained incompletely known or for which no recent collections were found. Of the 24 taxa documented from Patagonia, 15 species were assigned to 12 current sections in the genus Cortinarius. Analysis of spore ultrastructure showed that sequestrate forms of Patagonian Cortinarius lack a true perisporium.

Gerronema nemorale: first report of the genus and species from Pakistan

Basidiomata of a Gerronema species, collected in Murree, Punjab, Pakistan, have been confirmed as G. nemorale by morphological and ITS1-5.8S-ITS2 rDNA sequence analyses. This is the first report of the genus Gerronema from Pakistan, and the first record of G. nemorale for the South Asian region.

<p><strong>Morphology and molecular data of the species of <em>Suillus</em> (Suillaceae, Boletales) associated with <em>Pinus sibirica</em> at the European northeast of Russia</strong></p>

The genus Suillus represents the largest genus of the family Suillaceae, forming ectomycorrhizae with coniferous trees. Here, we presented the first results of molecular research (nrITS1-5.8S-ITS2 rDNA sequences) of the specimens of Suillus, forming ectomycorrhizae with Pinus sibirica, at the territory of European northeast of Russia. The six taxa (Suillus acidus var. intermedius, S. placidus, S. plorans subsp. plorans, S. plorans subsp. cyanescens, S. punctipes and S. sibiricus) are identified based on morphological and molecular evidence. The key for identification, full morphological descriptions, the color photos of basidiomata and information on their ecology and distribution in Russia and world are presented for these taxa. On the basis of the molecular approach, we confirmed the relevance of subspecies Suillus plorans subsp. cyanescens previously described only by morphological features. BLAST-analysis of Suillus placidus with untypical for this species brown pileus revealed 99% identity with the specimens of S. placidus from Asia, for which the color of pileus varies from white to brown.

Two new species of Physisporinus (Polyporales, Basidiomycota) from Yunnan, Southwest China

Based on morphological characteristics and molecular phylogenetic analysis using nuc rDNA ITS1-5.8S-ITS2 and 28S rDNA sequences, two new species of Physisporinus, Physisporinus castanopsidis sp. nov. and Physisporinus roseus sp. nov. are described from Yunnan Province, Southwest China. Physisporinus castanopsidis is characterised by resupinate, snow white and waxy basidiocarps which become pale brown when bruised, abundant hymenial cystidia and cystidia-like hyphae at dissepiment edge, generative hyphae with swollen tips, distinctly ovoid basidiospores measuring 4.8–5.6 × 3.6–4.2 μm and growing on rotten wood or roots of Castanopsis. Physisporinus roseus is characterised by perennial, resupinate and thick basidiomata with rose fresh pores which becoming vinaceous grey up on drying, a distinct context layer present among tube layers, abundant clavate, smooth cystidia and subglobose basidiospores measuring 3.5–4.1 × 3.1–3.8 μm.

Redescription and synonymization of Oscheius citri Tabassum, Shahina, Nasira and Erum, 2016 (Rhabditida, Rhabditidae) from India and its taxonomical consequences.

A population of a nematode species belonging to the genus Oscheius was isolated in western Uttar Pradesh, India. Morphological and morphometrical studies on this species showed its high similarity with six species described previously from Pakistan (Oscheius citri, O. cobbi, O. cynodonti, O. esculentus, O. punctatus and O. sacchari). The molecular analysis of the ITS1-5.8S-ITS2 rDNA sequences of the Indian population and the six species described from Pakistan showed that all the sequences are almost identical. Thus, based on morphological and molecular characteristics, all of the six above-mentioned Pakistani species and Indian strain do not differ from each other, hence can be considered synonyms. The correct name for this taxon is the first described species O. citri. Additionally, the phylogenetic analysis of the 18S rDNA and the 28S rDNA sequences showed that Oscheius citri is sister to the clade formed by O. chongmingensis and O. rugaoensis from China. The high similarity of morphological and morphometric characteristics of O. citri and other species, O. maqbooli, O. nadarajani, O. niazii, O. shamimi and O. siddiqii, suggest their conspecificity; however, lack of molecular data for these species does not allow this hypothesis to be tested.

Intra-genomic variability and pseudogenes in ribosomal ITS regions of Paraplagusia blochii (Pleuronectiformes: Cynoglossidae)

Abstract Eukaryotic nuclear ribosomal DNA (rDNA) typically evolves in a concerted manner, in which hundreds of rDNA sequences within species show little or no variations, whereas the sequences of different species diverge. There are few studies of the internal transcribed spacer regions (ITS1-5.8S-ITS2) in teleostean fishes and only one report on flatfishes. Here, we reported the discovery of two types of highly divergent ITS1-5.8S-ITS2 rDNA sequences (Type A and B) in the genome of the Bloch’s tonguesole, Paraplagusia blochii. These sequences mainly differ in sequence length, secondary structure, and minimum free energy. According to the potential features of pseudogenes, Type B sequences are speculated to be putative pseudogenic ITS regions. Cluster analyses also supported two major clades that corresponded to the sequence type. To the best of our knowledge, this is the first report of the ITS regions of tonguefish, and may therefore provide useful information for future studies of the rDNA of flatfishes as well as the patterns of rDNA evolution in teleostean fishes.

The N-glycans of Chlorella sorokiniana and a related strain contain arabinose but have strikingly different structures.

The many emerging applications of microalgae such as Chlorella also instigate interest in their ability to conduct protein modifications such as N-glycosylation. Chlorella vulgaris has recently been shown to equip its proteins with highly O-methylated oligomannosidic N-glycans. Two other frequently occurring species names are Chlorella sorokiniana and Chlorella pyrenoidosa-even though the latter is taxonomically ill defined. We analyzed by mass spectrometry and nuclear magnetic resonance spectroscopy the N-glycans of type culture collection strains of C. sorokiniana and of a commercial product labeled C. pyrenoidosa. Both samples contained arabinose, which has hitherto not been found in N-glycans. Apart from this only commonality, the structures differed fundamentally from each other and from that of N-glycans of land plants. Despite these differences, the two algae lines exhibited considerable homology in their ITS1-5.8S-ITS2 rDNA sequences. These drastic differences of N-glycan structures between species belonging to the very same genus provoke questions as to the biological function on a unicellular organism.

Diversity of exotic ectomycorrhizal Rhizopogon from pine plantations in Patagonia

ABSTRACTWe present an account of Rhizopogon introduced from plantings of exotic pine plantations in Argentine Patagonia. Nuc rDNA internal transcribed spacer ITS1-5.8S-ITS2 (ITS) and nuc 28S rDNA (28S) sequences were used to identify specimens from Argentina and examine their relationships with geographically different Rhizopogon species. Based on phylogenetic analyses, we confirm that four species of Rhizopogon occur in pine plantations across Patagonia. Several Rhizopogon collections from Pinus ponderosa plantations across different provinces cluster with R. arctostaphyli, a species within R. subg. Amylopogon. The majority of Patagonian Rhizopogon, however, form three different lineages in R. subg. Roseoli. The first of these, R. roseolus sensu Trappe, includes numerous collections from Pinus ponderosa, P. contorta, and P. radiata stands of North American affiliation. The second, R. roseolus sensu Martin and Garcia from P. ponderosa plantations, clusters in clade IIIa of the R. roseolus complex, which also includes the holotype collection of R. mohelnensis from the Czech Republic. The third species in R. subg. Roseoli, and fourth species overall from Patagonia, is R. granuloflavus from Pinus ponderosa plantations. Multiplex polymerase chain reaction (PCR) of numerous Roseoli samples failed to produce an amplicon indicative of either Japanese or New Zealand shoro.

Redescription and supplementary molecular characteristics of Aspidogaster ijimai Kawamura, 1915 (Trematoda, Aspidogastrea, Aspidogastridae), a parasite of Cyprinus carpio Linnaeus, 1758 s. lato (Actinopterygii) and freshwater bivalves in East Asia

A detailed morphological description and ribosomal DNA (rDNA) sequence molecular data for Aspidogaster ijimai from Japan are provided. Morphological analysis, including a description of the cirrus-sac, indicate the conspecificity of Japanese and continental East Asian A. ijimai specimens. Analysis of ITS1-5.8S-ITS2 rDNA sequences of Japanese, Chinese and Russian specimens confirmed the morphological results. Phylogenetic analysis using ITS rDNA sequences confirmed that A. ijimai is a sister species for Aspidogaster chongqingensis. Median-joining network analysis showed an initial molecular differentiation step of Russian specimens from group of Japanese-Chinese samples. Our 28S rDNA results based on maximum likelihood (ML) and Bayesian (BI) phylogenetic analyses indicated well-supported monophyly of the Aspidogaster conchicola + A. ijimai group, a finding that indicates that these species are congeneric. At the same time, our data demonstrated that the genus Lobatostoma is paraphyletic and the family Aspidogastridae is polyphyletic, results that confirm previous studies.

Diversity and phylogenetic relationships of European species of Crepidostomum Braun, 1900 (Trematoda: Allocreadiidae) based on rDNA, with special reference to Crepidostomum oschmarini Zhokhov & Pugacheva, 1998

BackgroundWithin the genus Crepidostomum Braun, 1900, identification of species and taxonomic decisions made only on the basis of adult morphology have resulted in great problems associated with evaluating actual diversity and validity of species. Life-cycle data, while equal in importance to adult characters, are scarce, controversial or incomplete for most Crepidostomum spp. In this study, rDNA sequences generated from adult and larval Crepidostomum spp. and some other allocreadiid species were analysed to reveal the diversity and phylogenetic relationships of the species and their host range. Detailed morphological description based on light microscopy, SEM tegumental surface topography and genetic data are provided for the poorly known trematode C. oschmarini Zhokhov & Pugacheva, 1998 found in the intestine of two teleost fish species, Barbatula barbatula (L.) and Cottus gobio L.ResultsWe characterized 27 isolates of adult and larval parasites. Based on newly obtained 28S and ITS1-5.8S-ITS2 rDNA sequences, new intermediate and final hosts were ascertained, and life-cycles clarified for some allocreadiids. New knowledge on the diversity and phylogenetic relationships of European Crepidostomum spp. was gained. The validity of C. oschmarini was verified based on comparative sequence analysis. Ophthalmoxiphidiocercariae of C. oschmarini were recorded in sphaeriid bivalves Pisidium (Euglesa) casertanum (Poli). Additionally, morphological differences between gravid specimens of C. oschmarini and other related species were observed.ConclusionsSpecies of the Allocreadiidae parasitizing fishes in Europe are distributed among two monophyletic genera, Allocreadium and Bunodera, and two paraphyletic Crepidostomum clades. A complex of Crepidostomum metoecus (syn. C. nemachilus), C. oschmarini and Crepidostomum sp. 2 clustered in one clade, and a complex of C. farionis, Crepidostomum sp. 1 and, probably, C. wikgreni in the other. Molecular data indicated that C. oschmarini and Crepidostomum sp. 2 presumably have a wide geographical distribution in Europe. The new data provided evidence that Crepidostomum is a more diverse genus than can be judged from morphological data and host switching in this genus may occur independently of fish-host phylogeny.

Keratinophilic fungi from the vicinity of salt pan soils of Sambhar lake Rajasthan (India)

Forty soil samples were collected from seven sites in the vicinity of Sambhar lake Rajasthan, India and screened for the presence of keratinophilic fungi using hair baiting techniques for isolation. Seventeen isolates were recovered and identified. The cultures were identified by recognition of their macro- and micro- morphological features. Their identification was confirmed by BLAST using ITS1-5.8S-ITS2 rDNA region and sequences have been deposited in NCBI data base. A total of 34 species belonging to 29 genera were isolated. Among the dermatophytes and related keratinophilic fungi Chrysosporium indicum was predominant followed by Ctenomyces serratus, C. tropicum, Keratinophyton durus, Auxarthron conjugatum, Gymnascella dankaliensis, Gymnoascoideus petalosporus and Uncinocarpus reesii. Twenty-six species belonging to 22 genera represented other species. Our study indicates that keratinophilic fungi and species are found in the soils at the vicinity of the Sambhar Lake, and human activities can be the potential source of pathogenic fungi.

DESCRIPTION OF MUCOR PERNAMBUCOENSIS (MUCORALES, MUCOROMYCOTA), A NEW SPECIES ISOLATED FROM THE BRAZILIAN UPLAND RAINFOREST

The Mucor genus mostly comprises saprobe specimens which are commonly isolated from herbivore dung, fruit and soil. Morphologically, Mucor specimens produce simple or branched sporangiophores without basal rhizoids and non-apophysate sporangia. During a survey of Mucorales in soil from an upland rainforest area in Pernambuco, Brazil, one specimen of Mucor was isolated and characterized based on morphological, physiological and molecular data (ITS1-5.8S-ITS2 and LSU rDNA sequences). The specimen is characterized by producing strongly sympodially branched sporangiophores and sporangiospores which can contain one or more granules at each end. The columellae are frequently globose or obovoid, some ovoid or cylindrical with a truncate base, rarely piriform. It grew better at 25ºC, with no development at 35ºC. Based on the evidence of the analyzed datasets, a new species of Mucor is proposed.

Marked intra-genomic variation and pseudogenes in the ITS1-5.8S-ITS2 rDNA of Symphurus plagiusa (Pleuronectiformes: Cynoglossidae)

AbstractThe eukaryotic ribosomal DNA (rDNA) cluster consists of multiple copies of three genes (18S, 5.8S, and 28S rDNA) and two internal transcribed spacers (ITS1 and ITS2). In recent years, an increasing number of rDNA sequence polymorphisms have been identified in numerous species. In the present study, we provide 33 complete ITS (ITS1-5.8S-ITS2) sequences from twoSymphurus plagiusaindividuals. To the best of our knowledge, these sequences are the first detailed information on ITS sequences in Pleuronectiformes. Here, two divergent types (Type A and B) of the ITS1-5.8S-ITS2 rDNA sequence were found, which mainly differ in sequence length, GC content, nucleotide diversity (π), secondary structure and minimum free energy. The ITS1-5.8S-ITS2 rDNA sequence of Type B was speculated to be a putative pseudogene according to pseudogene identification criteria. Cluster analysis showed that sequences from the same type clustered into one group and two major groups were formed. The high degree of ITS1-5.8S-ITS2 sequence polymorphism at the intra-specific level indicated that theS. plagiusagenome has evolved in a non-concerted evolutionary manner. These results not only provide useful data for ribosomal pseudogene identification, but also further contribute to the study of rDNA evolution in teleostean genomes.

Molecular phylogeny and morphologic data of strains of the genus Coelastrella (Chlorophyta, Scenedesmaceae) from a tropical region in North America (Yucatan Peninsula)

Background: Scenedesmaceae family exhibits great morphological variability. High phenotypic plasticity and the presence of cryptic species have resulted in taxonomic re-assignments of Scenedesmaceae members.
 Study strains: Strains CORE-1, CORE-2 and CORE-3 were characterized.
 Study site: Yucatan Peninsula
 Methods: Morphological analyses were executed by optical and scanning electron microscopy. Phylogenetic relationships were examined by ITS-2 and ITS1-5.8S-ITS2 rDNA regions.
 Results: Optical and scanning electron microscopy analyses indicated spherical to ellipsoidal cells and autospore formation correspond to members of the family Scenedesmaceae, as well as observable pyrenoid starch plates. Detailed morphology analysis indicated that CORE-1 had visible granulations dispersed on the cell wall, suggesting identity with Verrucodesmus verrucosus . However CORE-1 did not show genetic relations with this species, and was instead clustered close to the genus Coelastrella . CORE-2 did not show any particular structure or ornamentation, but it did show genetic relations with Coelastrella with good support. CORE-3 showed meridional ribs from end to end, one of them forked and well pronounced, and orange cells in older cultures characteristic of Coelastrella specimens. Phylogenetic trees of ITS-2 and ITS1-5.8S-ITS2 rDNA sequences indicated with good support that all strains were related to the genus Coelastrella despite their morphologic differences.
 Conclusions: This study reports freshwater Coelastrella strains from a tropical region in North America (Yucatan Peninsula) for the first time. The results contribute to knowledge of Coelastrella species, and the fact that they do not always show structures that are useful for taxonomic assignment, probably as a result of phenotypic plasticity.

New molecular and morphological data for opecoelid digeneans in two Mediterranean sparid fishes with descriptions of Macvicaria gibsoni n. sp. and M. crassigula (Linton, 1910) (sensu stricto).

Molecular and morphological data were gathered for specimens of species of Macvicaria Gibson & Bray, 1982 and Pseudopycnadena Saad-Fares & Maillard, 1986 (Digenea: Opecoelidae) collected from two sparid fishes, Diplodus vulgaris (Geoffroy Saint-Hilaire) and Sparus aurata L., off the Algerian coast of the Western Mediterranean. Phylogenetic analyses based on ITS1-5.8S-ITS2 and partial 28S rDNA sequences provided evidence for the distinct species status of eight Mediterranean species of Macvicaria. Novel molecular data are provided for four species, M. gibsoni n. sp. and M. crassigula (Linton, 1910) (sensu stricto) based on specimens from D. vulgaris, and M. mormyri (Stossich, 1885) and M. maamouriae Antar, Georgieva, Gargouri & Kostadinova, 2015 based on specimens from S. aurata; descriptions of the molecular voucher material of the former three species are provided. Two species were delineated within the "crassigula" species complex of Macvicaria, M. gibsoni n. sp. and M. crassigula (s. str.), the distinctive differentiating features being the distribution of the dorsal vitelline fields in the forebody, confluent in M. gibsoni n. sp. and non-confluent in M. crassigula (s. str.), and the molecular data for both markers. Sequences associated with morphological description are also provided for the type-species of Pseudopycnadena, P. fischthali Saad-Fares & Maillard, 1986, based on material from D. vulgaris.

Production of paclitaxel with anticancer activity by two local fungal endophytes, Aspergillus fumigatus and Alternaria tenuissima.

Among 60 fungal endophytes isolated from twigs, bark, and mature leaves of different plant species, two fungal isolates named TXD105 and TER995 were capable of producing paclitaxel in amounts of up to 84.41 and 37.92μg L-1, respectively. Based on macroscopic and microscopic characteristics, ITS1-5.8S-ITS2 rDNA sequence, and phylogenetic characteristic analysis, the two respective isolates were identified as Aspergillus fumigatus and Alternaria tenuissima. In the effort to increase paclitaxel magnitude by the two fungal strains, several fermentation conditions including selection of the proper fermentation medium, agitation rate, incubation temperature, fermentation period, medium pH, medium volume, and inoculum nature (size and age of inoculum) were tried. Fermentation process carried out in M1D medium (pH6.0) and maintained at 120rpm for 10days and at 25°C using 4% (v/v) inoculum of 5-day-old culture stimulated the highest paclitaxel production to attain 307.03μg L-1 by the A. fumigatus strain. In the case of the A. tenuissima strain, fermentation conditions conducted in flask basal medium (pH6.0) and maintained at 120rpm for 14days and at 25°C using 8% (v/v) inoculum of 7-day-old culture were found the most favorable to attain the highest paclitaxel production of 124.32μg L-1. Using the MTT-based assay, fungal paclitaxel significantly inhibited the proliferation of five different cancer cell lines with 50% inhibitory concentration values varied from 3.04 to 14.8μg mL-1. Hence, these findings offer new and alternate sources with excellent biotechnological potential for paclitaxel production by fungal fermentation.

Phylogenetic relationships among European and Asian representatives of the genus Aspidogaster Baer, 1827 (Trematoda: Aspidogastrea) inferred from molecular data.

In the present study, phylogenetic relationships of European and Far Eastern representatives of the genus Aspidogaster Baer, 1827 were analysed: A. conchicola Baer, 1827, A. limacoides Diesing, 1834, A. ijimai Kawamura, 1915 and A. chongqingensis Wei, Huang & Dai, 2001. Based on ITS1-5.8S-ITS2 rDNA sequence data, an obvious differentiation was seen between specimens of A. limacoides sensu stricto from the European part of Russia and A. limacoides sensu Chen et al., 2010 from China (13.7%); the latter parasites were recognized as A. chongqingensis. Aspidogaster chongqingensis was more closely related to A. ijimai than to A. limacoides s. str. Specimens of A. ijimai from the Amur River, Khanka Lake (Russian Far East) and China were grouped into a single clade with low intra specific molecular differentiation (d = 0-0.3%). Specimens of A. conchicola from the European part of Russia, the Russian Far East and China also formed a single distinct clade. Genetic differentiation between European and Chinese samples of this species was two times lower (d = 0.45%) than between Russian Far East and European or Chinese samples (d = 0.96%), suggesting a long-term separate existence of A. conchicola in the Russian Far East.