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Intracellular parasites of the genus Glugea Thélohan, 1891 (Microsporidia) comprise about 34 putative species capable of causing high morbidity and mortality in freshwater and marine teleost fishes. In this study, we report on the first mass mortality event associated with Glugea sp. infecting free‐ranging round sardinella Sardinella aurita in the southern Tyrrhenian Sea (Italy). Here, we describe the ultrastructure of mature spores of this microsporidian and characterize it molecularly, as well as report its phylogenetic position. Most of the affected fish showed an irregular swelling of its abdomen. At necropsy, a variable number of xenomas, spherical to ellipsoidal in shape, were found in the peritoneal cavity strongly attached to the viscera of all fish. Histological analysis revealed varying severity of chronic inflammation along with occasional necrosis in visceral organs associated with multiple xenoma proliferation. These pathological findings were considered the main cause of this mass mortality event. Morphologically, the present material was closely related to G. sardinellesis and G. thunni. The phylogenetically closest taxa to the newly SSU rDNA sequence were G. thunni and an erroneusly identified G. plecoglossi, which were very closely related to each other, also suggesting that all these sequences might belong to the same species. [ABSTRACT FROM AUTHOR]

Series Maximi is a group within Desmodesmus (Chlorophyta) which contains the three species D. maximus, D. perforatus and D. tropicus. Besides their large cell sizes, the most striking morphological trait unique to the members of this genus is the presence of large perforations between the coenobial cells. The perforations are either present (D. perforatus and D. tropicus) or the space between the cells is completely sealed (D. maximus). We report here a fourth species of the series based on two strains (AICB 1155 and AICB 1572) from freshwater environments of the Danube Delta, Romania. The ultrastructure of the cell walls revealed a partial closure of the space between the cells which creates slightly visible perforations in light microscopy. Analyses of DNA sequences and secondary structure of the ITS2 fragment by coalescent (PTP, GMYC), distance (ASAP), and evolutionary modelbased methods (ML, BI) indicated a fourth candidate species which included both the AICB strains investigated and other strains with similar morphological traits from reference literature. Despite its poor representation in public databases, analysis of the SSU rDNA gene for the series Maximi strengthened the ITS2 results. Therefore, based on its larger cell sizes relative to the other members of the series, cell morphology, the presence of partial perforations and other peculiarities of the cell wall ultrastructure, the independent phylogenetic position, CBCs analysis, and a different 'DNA signature' within the ITS2 fragment we suggest that this clade should be described as a new taxon of the series Maximi, Desmodesmus pseudoperforatus sp. nov. Morphological differences and DNA-based lines of evidence indicate new species. Microperforations of the space between the coenobial cells. Strains have the largest cell sizes in the series Maximi. [ABSTRACT FROM AUTHOR]

Ciliates are an important ecological component in the microbial food web, but few studies have been conducted on the spatial distribution of small-sized planktonic ciliate communities in the East China Sea (ECS). Investigating ciliate communities using conventional morphological approaches is particularly difficult for the small, fragile, and naked species. Therefore, we applied DNA metabarcoding analysis to explore the spatial pattern of small-sized planktonic ciliate community structure within the surface, deep chlorophyll maximum (DCM), and bottom layers. Results showed the cosmopolitan species, Leegaardiella sp., was dominant and widespread in the ECS. The relative abundance of the mixotrophic family Tontonnidae decreased in the deeper layer. We characterized water masses of the ECS using environmental variables. In nano-sized ciliate communities, non-metric multidimensional scaling (NMDS) plots revealed a correlation with temperature, salinity, density, and depth. The circulation patterns were similar to cluster analysis results, suggesting that hydrographic conditions shaped small-sized ciliate community composition. [ABSTRACT FROM AUTHOR]

Rhodomonas (Cryptophyceae) and species assigned to this genus have undergone numerous taxonomic revisions. This also applies to R. marina studied here as it was originally assigned as a species of Cryptomonas and later considered a variation of R. baltica, the type species. Despite being described more than 130 years ago, R. marina still lacks a comprehensive characterization. Light and electron microscopy were employed to delineate a strain from western Greenland. The living cells were 18 µm long and 9 µm wide, elliptical in shape with a pointed to rounded posterior and truncated anterior in lateral view. Two sub-equal flagella emerged from a vestibulum, where also a furrow extended. In transmission electron microscopy, the furrow was associated with a tubular gullet and the pyrenoid embedded in a deeply lobed chloroplast. The chloroplast contained DNA in perforations and was surrounded by starch grains. A tubular nucleomorph was enclosed within the pyrenoid matrix. In scanning electron microscopy, the inner periplast consisted of rectangular plates with rounded edges and posteriorly these were replaced by a sheet-like structure. The water-soluble pigment was Crypto-Phycoerythrin type I (Cr-PE 545). A phylogenetic inference based on SSU rDNA confirmed the identity of strain S18 as a species of Rhodomonas as it clustered with congeners but also Rhinomonas, Storeatula, and Pyrenomonas. These genera formed a monophyletic clade separated from a diverse assemblage of other cryptophyte genera. To further explore the phylogeny of R. marina a concatenated phylogenetic analysis based on the SSU rDNA-ITS1-5.8S rDNA-ITS2-LSU rDNA region was performed but included only closely related species. The secondary structure of nuclear internal transcribed spacer 2 was predicted and compared to similar structures in related species. Using morphological and molecular signatures as diagnostic features the description of R. marina was emended. [ABSTRACT FROM AUTHOR]

Nodular gill disease (NGD) is an emerging condition associated with amoeba trophozoites in freshwater salmonid farms. However, unambiguous identification of the pathogens still must be achieved. This study aimed to identify the amoeba species involved in periodic NGD outbreaks in two rainbow trout (Oncorhynchus mykiss) farms in Northeastern Italy. During four episodes (February–April 2023), 88 fish were euthanized, and their gills were evaluated by macroscopic, microscopic and histopathological examination. The macroscopic and microscopic severity of the lesions and the degree of amoebae infestation were scored and statistically evaluated. One gill arch from each animal was put on non‐nutrient agar (NNA) Petri dishes for amoeba isolation, cultivation and subsequent identification with SSU rDNA sequencing. Histopathology confirmed moderate to severe lesions consistent with NGD and mild to moderate amoeba infestation. The presence of amoebae was significantly correlated with lesion severity. Light microscopy of cultured amoebae strains and SSU rDNA analysis revealed the presence of a previously characterized amoeba Naegleria sp. strain GERK and several new strains: two strains from Hartmannelidae, three vannelid amoebae from the genus Ripella and cercozoan amoeba Rosculus. Despite the uncertainty in NGD etiopathogenesis and amoebae pathogenic role, identifying known and new amoebae leans towards a possible multi‐aetiological origin. [ABSTRACT FROM AUTHOR]

A brain-infecting myxozoan, Kudoa yasunagai (Hsieh & Chen, 1984), was identified using both morphological and molecular methods in a marine fish from Van Phong Bay, Khanh Hoa province, Vietnam. Cysts containing spores were observed in the brain of one out of 10 Siganus virgatus (Valenciennes) individuals (10%). The myxospores were radially symmetrical, containing a majority of 7 equal shell valves and polar capsules. The spores measured 6.6 ± 0.1 (6.4-6.7) µm in length, 7.6 ± 0.5 (7.0-8.4) µm in width, and 7.0 ± 0.4 (6.5-7.7) µm in thickness. Polar capsules measured 2.8 ± 0.2 (2.6-3.0) µm in length and 1.4 ± 0.1 (1.2-1.5) µm in width, containing a filament inside. The SSU rDNA sequence from the Vietnamese specimen showed > 99.94 % identity with K. yasunagai from Japan and Australia. This report marks a new geographical and host record for K. yasunagai. [ABSTRACT FROM AUTHOR]

We performed a parasitological examination of the gastrointestinal tract of farmed ring-necked pheasants (Phasianus colchicus karpowi) on two farms in Ehime, Japan. Fecal examination through flotation and sedimentation methods (43, 103, and 50 samples in three consecutive years from 2020, respectively) detected coccidian oocysts (5–58%), or capillarid (40–56%) and heterakid eggs (45–72%). Following artificial sporology, most sporulated coccidian oocysts were ellipsoidal without micropyle nor residuum, but with 1–3 polar refractile granules, morphologically reminiscent of Eimeria phasiani (Apicomplexa: Eucoccidiorida: Eimeriidae). Intensive sequencing of mitochondrial cytochrome c oxidase subunit I gene (cox-1) using pan-eimerian primers and multiple oocyst samples from different pheasants indicated a single species. We characterized, for the first time, the cox-1 sequence of E. phasiani, known to be prevalent in wild and captive ring-necked pheasants worldwide. Worm recovery under a dissection microscope revealed two capillariid and one heterakid nematode species: Eucoleus perforans (Nematoda: Trichocephalida: Capillariidae) in the esophageal epithelium (prevalence, 8–73%), Capillaria phasianina (Capillariidae) in the cecal mucosa (10–87%), and Heterakis gallinarum (Nematoda: Ascaridida: Heterakidae) in the cecal lumen (69–88%). The small subunit ribosomal RNA gene (SSU rDNA) of E. perforans was perfectly identical to that in a previous isolate from farmed Japanese green pheasants (Phasianus colchicus versicolor) at a distant locality in Japan. The SSU rDNA of C. phasianina was characterized, for the first time, demonstrating a sister relationship with Capillaria anatis, parasites found in the ceca of domestic ducks, geese, and various wild anatid birds. [ABSTRACT FROM AUTHOR]

Objective: Myxosporidiosis of bagrid fishes has been a focus of aquaculture research in recent years. The purpose of this study is to characterize a novel myxobolid, named Myxobolus xiushanensis n. sp., infecting Yellowhead Catfish Tachysurus fulvidraco in China. Methods: We used molecular biology, morphology, phylogeny, and histopathology in the present study. Result: Mature myxospores were circular to ellipsoidal in valve view, measuring 12.2 ± 0.4 μm (mean ± SD; range = 11.2–13.2 μm) in length and 10.6 ± 0.4 μm (9.5–11.1 μm) in width. Two oval polar capsules were equal in width (3.4 ± 0.2 μm; 3.0–3.8 μm) but slightly unequal in length: 5.6 ± 0.3 μm (5.3–6.1 μm) and 4.7 ± 0.2 μm (4.4–5.5 μm). The polar capsule was packed with five to seven spirals of polar tubules. Histopathological investigation demonstrated that the plasmodium under the cuticular layer of the gill arch only induced a local inflammatory response and did not cause serious damage to the gill arch's internal structure. The two small subunit (SSU) ribosomal DNA sequences of M. xiushanensis n. sp. showed 100% similarity and uniqueness, and the highest similarity with other myxosporean sequences in GenBank was 90.27% (query coverage = 94%). The secondary structures of the SSU ribosomal RNA revealed that the present species was distinctly different from related species in regions V4 and V7. Phylogenetic analysis showed that M. xiushanensis n. sp. clustered independently within a branch. Conclusion: These results enrich our understanding of the biodiversity of myxobolids infecting bagrid fishes and provide fundamental data for the diagnosis of myxosporidiosis. Impact statementThis study described Myxobolus xiushanensis n. sp. infecting the gill arch of Yellowhead Catfish Tachysurus fulvidraco in China. The results enrich our understanding of the biodiversity of myxobolids and provide fundamental data for the diagnosis of myxosporidiosis. [ABSTRACT FROM AUTHOR]

A new myxomycete species, Didymium arenosum, was described based on morphological evidence and phylogenetic analyses. The species was discovered in the arid region at the confluence of the Badain Jaran desert and Tengger desert on the leaves of Betula platyphylla and was cultivated in a moist chamber culture. Morphologically, the species is distinguished by the greenish-yellow calcium carbonate crystals on the surface and the spores covered with small warts, some of which are connected into a short line. A phylogenetic analysis of D. arenosum strongly supports its classification as a separate clade. The spore to spore agar culture of D. arenosum requires 23 days, and this study provides a detailed description of its life cycle.

Gentiana zollingeri is an annual photosynthetic plant that employs a mycoheterotrophic growth strategy during its underground seedling stage (initial mycoheterotrophy). Notably, the morphological characteristics of its flowering shoots, such as shoot size, leaf size, and leaf color, are highly variable, and it was hypothesized that these variations may be linked to nutritional mode. The morphological characteristics of G. zollingeri individuals were thus investigated alongside environmental factors, 13 C abundance, and diversity of colonizing arbuscular mycorrhizal (AM) fungi. The majority of G. zollingeri flowering individuals were found to exhibit a high affinity for the specific AM fungi that exclusively colonize roots of the mycoheterotrophic seedlings, while other phylogenetically diverse AM fungi could also be detected. The leaves to shoot dry weight ratio (leaf ratio) was negatively correlated with the canopy openness in the habitat, suggesting that leaf development is impeded in sunny conditions. Furthermore, the shoot weight of G. zollingeri was positively correlated with leaf 13 C abundance. Given that 13 C enrichment can provide indirect evidence of mycoheterotrophy in AM plants, the results suggest that the utilization of carbon obtained through mycoheterotrophy, at least during the underground seedling stage, is crucial for G. zollingeri. [ABSTRACT FROM AUTHOR]

Centrohelids (Haptista: Centroplasthelida) are axopodial protists with a remarkable diversity of external siliceous scale morphologies. It is believed that the last common ancestor of centrohelids had a double layer of siliceous scales composed of plate scales closer to a cell surface and spine scales radiating outwards. The characteristic morphotype of spine scales with a heart‐shaped base was once believed to be a unique feature of the genus Choanocystis, as it was defined by Siemensma and Roijackers (1988). Further research revealed that this morphology is present in different and sometimes distantly related lineages: Ozanamiidae, Meringosphaeridae, and Marophryidae. Here, we report the fourth clade, Pterocystidae, which is also revealed to contain representatives having this phenotype. Cernunnos gen. nov. is erected here to place Cernunnos uralica sp. nov., Cernunnos arctica sp. nov., Cernunnos america sp. nov., and Cernunnos antarctica Tikhonenkov et Mylnikov, 2010, Gerasimova comb. nov. C. uralica was studied with scanning electron microscopy and SSU rDNA sequencing. Molecular phylogenetic analysis placed it into marine environmental clade P within Pterocystida. The ubiquity of spine scales with heart‐shaped bases could be an example of parallel evolution, but taking into account the considerable similarity it is likely an ancestral trait, acquired from the last common ancestor of centrohelids. [ABSTRACT FROM AUTHOR]

A strain of oogamous biflagellate green alga was isolated during a study on soil algal diversity in the Russian Far East (Sakhalin Region, Iturup Island) and examined using an integrative approach. Phylogenetic analyses, based on the SSU rDNA gene, resolved the new strain as a part of the RL clade (sensu Watanabe and Nakada) within Oogamochlamydinia (Volvocales, Chlorophyceae). The strain was similar to members of the genus Oogamochlamys (parietal and massive cup-shaped chloroplasts; two apical contractile vacuoles), but was, however, distinguished from them based on the size and shape of the mature vegetative cells, the flagellar length, the presence of only one pyrenoid in both the mature vegetative cells and the zoospores, the anterior nucleus position, and the spermatozoids' shape. Although a concept of the genus Oogamochlamys has been compromised in recent phylogenetic analysis based on the SSU rDNA sequence data and its likely affinity to anisogamous Chlamydomonas allensworthii, we described the strain from Iturup Island as Oogamochlamys kurilensis sp. nov. [ABSTRACT FROM AUTHOR]

The global cultivation of common carp Cyprinus carpio is developed primarily for either food or recreational purposes and myxosporean infections causing significant economic losses are regularly troublesome for carp farmers. However, most myxosporean species are poorly characterized, making it difficult to correctly elaborate on their parasitism mode and determine pathogenicity. Here, based on an integrative approach, we supplemented fundamental information on three Myxobolus species infecting different carp lineages in China. Myxobolus elliptoides Wu et Chen, 1987; Nine new species of Myxosporida from freshwater fish of Wuhu lake, Hubei, China. Acta Hydrobiologica Sinica, 11, 161 formed yellowish pseudocysts in the anal fin of common carp and were observed with ellipsoidal myxospores and two polar capsules of distinct dimensions. The dermal tissue within the fin ray was regarded as the type site for growing plasmodia of M. elliptoides. Myxobolus basilamellaris Lom et Molnar, 1983; Myxobolus basilamellaris sp. n. (myxozoa, Myxosporea), a parasite of the gills of common carp (Cyprinus carpio L.). Folia Parasitologica, 30, 1 aggregated ellipsoidal myxospores at the base of the gill filaments of koi carp juvenile, causing significant tissue damage. Myxobolus artus Achmerov, 1960, enwrapped in diffuse pseudocysts, was observed throughout the trunk muscle of mirror carp. Its oblate myxospores were asymmetrical and contained two unequal‐sized polar capsules. According to the localization of large plasmodia, inter‐ and intramuscular preferences were displayed by M. artus. For precise species identification, we provided the SSU rDNA sequences for each species of Myxobolus. Among them, M. elliptoides was molecularly characterized for the first time, showing the highest 94.21% identity to Thelohanellus sinensis (KY469292). Phylogenetically, the affinity of both M. artus and M. basilamellaris to their conspecific species derived from different carp lineages was highly supported. Moreover, the intermixed cluster of Myxobolus species, including M. elliptoides, with those of Thelohanellus species provided evidence for querying the monophyletic evolution history of these taxa. This work updates the appreciation of the concerned species and enhances our understanding of the parasite fauna of common carp. [ABSTRACT FROM AUTHOR]

During a nematological survey in southern Iran, a population belonging to the family Tylenchidae was recovered from a tomato field in Bushehr province. The recovered population belongs to the genus Filenchus, was described and illustrated herein as F. multistriatus n. sp. It is mainly characterized by having a wide and low annulated lip region continuous with adjacent body; amphidial openings confined to the labial plate; four lines in lateral fields forming three bands, with the two outer bands broken by transverse, and the inner one broken by both transverse and longitudinal lines; and median bulb oval with visible valve and elongate-conoid tail uniformly and gradually narrowing toward the distal region, ending in a widely rounded tip. Its morphological and morphometric differences with three closely similar species were discussed. The phylogenetic relationships of the new species with other relevant genera and species were reconstructed using partial sequences of small, and large subunit ribosomal DNA (SSU and LSU rDNA) sequences. Morphometric and morphological data were also provided for an Iranian population of F. sandneri recovered from Bushehr province. Both populations were characterised using SEM data.

A new species from the family Tylenchidae was recovered in the grasslands of Isfahan province, Iran, and is herein described based on morphological and molecular data. Ottolenchus isfahanicus n. sp. is mainly characterized by having a faintly annulated cuticle; elongated, slightly sigmoid amphidial apertures developed metacorpus with distinct valve under LM; vulva located at 69.472.3% of body length; large spermatheca about 2.75 times of corresponding body width; and elongated conoid tail with broadly rounded tip. SEM observations showed that the lip region is smooth; the amphidial apertures are elongated, slightly sigmoid slits; and the lateral field is a simple band. It is further characterized by 477-to-515-μm-long females with delicate 5.7-to-6.9-μm-long stylets with small, slightly posteriorly sloping knobs, as well as functional males, in the population. The new species closely resembles O. facultativus, but is separated from it based on morphological and molecular data. It was further morphologically compared with O. discrepans, O. fungivorus, and O. sinipersici. The phylogenetic relationships of the new species with other relevant genera and species were reconstructed using near-full-length sequences of small subunit and D2-D3 expansion segments of large subunit (SSU and LSU D2-D3). In the inferred SSU phylogeny, the newly generated sequence of Ottolenchus isfahanicus n. sp. formed a clade with two sequences of O. sinipersici and sequences assigned to O. facultativus and O. fungivorus. In the inferred LSU phylogeny, the three newly generated sequences of the new species and LSU sequences of O. sinipersici and O. discrepans formed a clade.

Summary: A new species of Ektaphelenchinae was recovered from the bark of a dead date palm (Phoenix dactylifera) tree, and from a soil sample collected from the rhizosphere of gramineous grasses in Iraq and Iran, respectively. It was assigned to the genus Ektaphelenchus mainly by the lack of a functional anus and rectum, and having a conical posterior body end (tail) in female, not ending to a filiform tip, and males lacking a bursa. The recovered populations were described based on morphological and molecular data. Ektaphelenchus phoenicis n. sp. is characterised by 346-441 μ m long females, having three lines in lateral field, a 12.3-15.8 μ m long stylet with wide lumen lacking basal knobs or swellings, high lip region separated from the rest of body by a depression, metacorpus elliptical with refractive valve plates almost in the middle to slightly posterior, excretory pore posterior to metacorpus, postvulval uterine sac (PUS) 9.3-14.8 μ m long, usually containing sperm, posterior body end (tail) with ventrally bent distal end, males common in population with seven precloacal + cloacal + caudal papillae and slightly elevated cloacal lips under SEM, appearing as a differentiated flap-like structure under LM. The new species was morphologically compared with typologically similar species of Ektaphelenchus with a similar body size, namely: E. golestanicus , E. oleae and E. taiwanensis ; a similar female posterior body end, namely: E. cupressi , E. kanzakii , E. prolobos and E. riograndensis ; and E. goffarti having a similar postcloacal structure. The phylogenetic relationships of the new species with other relevant genera and species were reconstructed using near full length sequences of small and D2-D3 expansion segments of large subunit (SSU and LSU D2-D3) rDNA. In both inferred phylogenies, the newly generated sequences of Ektaphelenchus phoenicis n. sp. occupied a placement inside a maximally supported clade including sequences of three genera Ektaphelenchus , Ektaphelenchoides and Devibursaphelenchus. [ABSTRACT FROM AUTHOR]

The characteristics of two new benthic species of Pyramimonas isolated from coral rubble have been determined. One, P. superba sp. nov., most similar to P. lunata, has a morphological character suite and molecular phylogenetic signal supporting it as a member of the subgenus Trichocystis, despite its uniqueness in producing mucilage. The other, P. lamellipunctata sp. nov., also shows phylogenetic affiliation with the subgenus Trichocystis using partial SSU data. However, this second species aligns with muciferous punctate species using rbcL data, although the clade is problematic as it includes the genus Pterosperma. Morphologically, cells of P. lamellipunctata share many features with muciferous punctate species but also exhibit important disparities with this group, most notably a lack of mucilage, suggesting that they form a unique lineage. HIGHLIGHTS ● Two new species of Pyramimonas are indicated as members of the subgenus Trichocystis using SSU data.● rbcL data only supports this association for one of the new species and affiliates the other with muciferous species of the subgenus Punctatae.● Morphological data only partially supports the second affiliation with punctate species, thereby inferring a unique lineage. [ABSTRACT FROM AUTHOR]

The genus Tripos (the marine Ceratium) often comprises a major part of microphytoplankton in terms of abundance and diversity that plays an important role in annual primary production; however, it has received little attention in the Persian Gulf. The morphology and phylogeny of Tripos furca, T. massiliense, and T. concilians were investigated in the present research. Samples collected from the Persian Gulf were identified morphologically under an inverted microscope, and the SSU rDNA sequence from individual cells was amplified using a polymerase chain reaction. The SSU rDNA sequence was determined for Iranian strains of these species and registered in the GenBank. The results of the phylogenetic analysis indicated the formation of a monophyletic clade of the family Ceratiaceae with high support. In this clade, freshwater species of Ceratium were grouped in a highly supported subclade, and marine species comprised another subclade. These results well demonstrated the separation (divergence) of marine and freshwater species of Ceratium. Altogether, the present results agree with previous studies where a considerable evolutionary distance is suggested for marine and freshwater species and support the formation of two highly distinct monophyletic clades based on SSU rDNA and LSU rDNA fragments and the number of cingular plates. [ABSTRACT FROM AUTHOR]

Ribosomal intragenomic variability in prokaryotes and eukaryotes is a genomic feature commonly studied for its inflationary impact on molecular diversity assessments. However, the evolutionary mechanisms and distribution of this phenomenon within a microbial group are rarely explored. Here, we investigate the intragenomic variability in 33 species of planktonic foraminifera, calcifying marine protists, by inspecting 2,403 partial SSU sequences obtained from single-cell clone libraries. Our analyses show that polymorphisms are common among planktonic foraminifera species, but the number of polymorphic sites significantly differs among clades. With our molecular simulations, we could assess that most of these mutations are located in paired regions that do not affect the secondary structure of the SSU fragment. Finally, by mapping the number of polymorphic sites on the phylogeny of the clades, we were able to discuss the evolution and potential sources of intragenomic variability in planktonic foraminifera, linking this trait to the distinctive nuclear and genomic dynamics of this microbial group. [ABSTRACT FROM AUTHOR]

The Peritrichia is a speciose and morphologically distinctive assemblage of ciliated protists that was first observed by Antonie van Leeuwenhoek over 340 years ago. In the last two decades, the phylogenetic relationships of this group have been increasingly debated as morphological and molecular analyses have generated contrasting conclusions, mainly owing to limited sampling. In the present study, we performed expanded phylogenetic analyses of 152 sessilid peritrichs collected from 14 different provinces of China and 141 SSU rDNA peritrich sequences from GenBank. The results of the analyses revealed new divergent relationships between and within major clades that challenge the morphological classification of this group including, (1) the recovery of four major phylogenetically divergent clades in the monophyletic order Sessilida, (2) aboral structures such as the stalk and spasmoneme were evolutionary labile, (3) the stalk or/and spasmoneme was lost in each divergent clade indicating that parallel evolution occurred in sessilid peritrichs and (4) the life cycle and habit drive the diversity of aboral structures as well as diversification and evolution in peritrichs. [ABSTRACT FROM AUTHOR]

Sequences were obtained for 58 podolampadacean single cells from France, Reunion Island (French territories) and Japan (6 SSU rDNA only, 40 SSU+LSU and 12 LSU only). The sequenced taxa belong to five of the eight described genera: Podolampas, Blepharocysta, Lissodinium, Gaarderiella and Mysticella. Two new genera, Alatosphaera and Pseudalatosphaera, were erected to accommodate 'Blepharocysta' hermosillae and 'Blepharocysta' denticulata. Most genera are well supported by concatenated LSU–SSU rDNA phylogenies, with the least support for Lissodinium. Metabarcoding of podolampadaceans using the V4 region of SSU rDNA showed a resolution too low to discriminate genera or species. Roscoffia and Cabra are here considered podolampadaceans, whilst Lessardia is considered to belong in a separate family. The relationship of Rhinodinium to the Podolampadaceae needs further study. Desmoschisis was recorded for the first time in Alatosphaera and Pseudalatosphaera. Several ribotypes need further study to attribute a species name to them. [ABSTRACT FROM AUTHOR]

Ribosomal intragenomic variability in prokaryotes and eukaryotes is a genomic feature commonly studied for its inflationary impact on molecular diversity assessments. However, the evolutionary mechanisms and distribution of this phenomenon within a microbial group are rarely explored. Here, we investigate the intragenomic variability in 33 species of planktonic foraminifera, calcifying marine protists, by inspecting 2,403 partial SSU sequences obtained from single-cell clone libraries. Our analyses show that polymorphisms are common among planktonic foraminifera species, but the number of polymorphic sites significantly differs among clades. With our molecular simulations, we could assess that most of these mutations are located in paired regions that do not affect the secondary structure of the SSU fragment. Finally, by mapping the number of polymorphic sites on the phylogeny of the clades, we were able to discuss the evolution and potential sources of intragenomic variability in planktonic foraminifera, linking this trait to the distinctive nuclear and genomic dynamics of this microbial group.

We describe Parietochloris toyamaensis sp. nov. and verify the taxonomic status of P. bilobata (originally described as Neochloris and once combined with Ettlia), using ultrastructural and molecular analyses. P. toyamaensis was isolated from soil collected in Toyama, Japan. It had a parietal chloroplast with pyrenoids that were discontinuously covered with starch segments and penetrated more or less in parallel by thylakoid membranes, and reproduced by forming naked, somewhat dorsoventral, biflagellate zoospores. Two contractile vacuoles were in line lengthwise, located in the median ventral side of the zoospores, as in the type P. alveolaris. The basal apparatus components included a single microtubule in the dexter root. P. toyamaensis was separately resolved from other members of the genus in the 18S rDNA and ITS2 trees. Since the authentic strain ASIB V141 of P. bilobata (stored as Ettlia) has been lost, ASIB V143 was used as a reference in place of it. P. bilobata ASIB V143 was resolved in the 'Parietochloris sensu stricto' clade but not 'Lobosphaera' clade in the 18S rDNA tree, so taxonomically the combination of N. bilobata with Parietochloris as P. bilobata by Andreyeva was confirmed. In zoospores of the strains of P. bilobata, contractile vacuoles were located in the ventral side, as in P. alveolaris. The taxonomic relationship between P. bilobata and P. grandis, and evaluation of the unique position of contractile vacuoles in dorsoventral zoospores as one of the key characters of Parietochloris were discussed. Characterization of the species of Parietochloris by using ultrastructural and molecular data. Proposal of Parietochloris toyamaensis sp. nov. Verification of phylogenetic position of Parietochloris bilobata. [ABSTRACT FROM AUTHOR]

A new marine myxosporean, Myxidium tunisiensis n. sp. (Myxosporea: Myxidiidae), is described infecting the gallbladder of the rough skate Raja radula Delaroche, 1908 (Chondrichthyes: Rajidae) harvested from the Bay of Bizerte, Tunisia. Observed stages of the parasite were floating free in the bile. Plasmodia, disporic or polysporic, contain disporic pansporoblasts measuring 23.0–27.2 μm in maximum diameter and 21.0–25.5 μm in minimum diameter. Mature myxospores, which are elongated, typically fusiform measured 18.6 ± 1.7 (17.2–22.0) μm in length, 8.6 ± 1.2 (7.2–11.2) μm in width and 8.2 ± 0.9 (6.4–10.1) in thickness. Myxospore valves are symmetrical with 9–10 longitudinal striations. Two polar capsules, pyriform, were equal in size, measuring 5.8 ± 0.4 (5.2–6.7) μm in length and 3.1 ± 0.2 (3.0–3.2) μm in width, with 5–6 polar filament turns. The infection was prevalent throughout the year with the highest prevalence in autumn (81.8%) and the lowest in winter (32.3%). The seasonal prevalence of M. tunisiensis n. sp. in the Bay of Bizerte appeared to fluctuate according to seawater temperature. The morphological and morphometrical differences with all Myxidium spp. described so far, complemented by molecular data, prove clearly that the present species is a new member of the genus Myxidium. The SSU rDNA phylogenetic analyses revealed that Myxidium tunisiensis n. sp. clustered within the oligochaete-gallbladder clade in a basal position to the marine subclade of Myxidium baueri and Myxidium coryphaenoideum. While the new species branching pattern is stable in the ML and the BI analyses, it changed in the MP analysis. This is the first molecular study of a Myxidium species infecting an elasmobranch host inhabiting the Mediterranean Sea. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Hydrobiology is the property of Editorial Department of Journal of Hydrobiology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Hydrobiology is the property of Editorial Department of Journal of Hydrobiology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The genus Operculina, a large symbiont-bearing benthic foraminifer, is characterized by high morphological variability showing thick involute to intermediate semi-involute to flat evolute tests. Different morphotypes are either considered as ecophenotypes or distinct species. In order to test the hypothesis of ecophenotypes versus different species, a single cell high throughput sequencing approach was applied to assess the interspecific diversity of Operculina. This results in two groups of ribotypes, one corresponding to Operculina ammonoides/Operculina discoidalis, the other containing Operculina complanata/Operculina elegans. These groups can also be separated morphologically. Therefore, O. complanata and O. elegans represent a single species and the latter can be regarded as a junior synonym of O. complanata. Operculina ammonoides and O. discoidalis also form a single species, which makes the latter a junior synonym of O. ammonoides. Because generic differences in Operculina species are manifested in morphology and molecular genetics, the genus Neoassilina with the designated species Neoassilina ammonoides is installed. Additional analysis of ribosomal SSU rDNA data of eight recent nummulitid genera confirms the obtained high troughput sequencing results and further shows that Palaeonummulites venosus builds a clade with O. complanata that branches at the base of other Nummulitidae containing Planostegina, Planoperculina, Cycloclypeus, Heterostegina, Operculinella and Neoassilina. [ABSTRACT FROM AUTHOR]

A new species of green coccoid algae, Mychonastes hindakii sp. nov., was isolated from the River Moscow (Russia, Moscow). The taxon is described using morphological and molecular methods. Mychonastes hindakii sp. nov. belongs to the group of species of the genus Mychonastes with spherical single cells joined with mucilaginous, irregularly shaped stalks. A comparison of ITS2 rDNA sequences and its secondary structures combined with the compensatory base changes approach confirms the separation between Mychonastes hindakii and other species of the genus. Mychonastes hindakii sp. nov. represents a cryptic species that can only be reliably identified using molecular data. [ABSTRACT FROM AUTHOR]

Many filamentous and sarcinoid terrestrial or freshwater green algae that were previously assigned to the Chlorophyceae are members of lineages belonging to the class Ulvophyceae. One of these lineages is the Planophila-clade (Ulotrichales). Some genera in this clade share similar morphology: cell packages forming branched pseudofilaments, uniseriate or sometimes biseriate filaments, often embedded in common mucilage. During a study on soil algal diversity in the temperate monsoon climate zone in Russia (Primorsky Territory, Vladivostok), we isolated a strain of sarcinoid green alga and examined it using an integrative approach. SSU and ITS rDNA sequence data, morphological characteristics, and life cycle features differentiated this strain from closely related genera of the order Ulotrichales and led us to describe it as Ulosarcina terrestrica gen. et sp. nov. [ABSTRACT FROM AUTHOR]

A new species of the genus Boleodorus, recovered from southern Iran, is described and illustrated based upon morphological and molecular data. B. bushehrensis n. sp. is mainly characterized by having a wide and low cephalic region (which is continuous with the adjacent body), the oral aperture in a depression in side view under a light microscope, four lines in the lateral field, weak metacorpus with a vestigial-to-invisible valve, and short (26–38 mm long) hooked tail with rounded tip. The females are 334–464 mm long and have a spherical spermatheca filled with spheroid sperm; males have 11.5- to 12.0-mm-long spicules and weakly developed bursa. The new species has an annulated low cephalic region, four large cephalic papillae, and small crescent-shaped amphidial openings when observed by scanning electron microscopy (SEM). Its morphological and morphometric differences with seven known species are discussed. The phylogenetic relationships of the new species with other relevant genera and species have been studied using partial sequences of small and large subunit ribosomal DNA (SSU and LSU rDNA). In both the SSU and LSU phylogenies, the sequences of B. bushehrensis n. sp. and other Boleodorus spp. formed a clade. A second species, B. thylactus, when studied under SEM, has a raised, smooth cephalic region, four large cephalic papillae, and oblique amphidial slits, with the oral opening in a depression.

The coastal waters of Vietnam are home to a wide diversity of fishes, but the parasite diversity of these potential hosts is much less well characterized. To begin addressing this knowledge gap, we carried out surveys of myxozoan parasites in fishes collected from Nha Trang Bay in Vietnam's East Sea in 2018–2019. Mugilid fishes were collected in March–April 2018, January–February 2019, and November–December 2019, and examined for myxozoans. Myxospores consistent with those of the genus Ellipsomyxa were found in the gall bladder of four mullet species, and we thoroughly characterized those from Planiliza melinoptera. Myxospores were elliptoid and devoid of striation, with a distinct sinuous suture line. Polar capsules were pyriform and oriented toward the poles of the spore. Morphological features were compared to nominal species and this species from Vietnam was distinct. Phylogenetic analysis based on partial small subunit rDNA sequence revealed that broadly, Ellipsomyxa species split into three phylogenetic lineages, and although in some branches there are groupings by host family, habitat or locality, there are no clear phylogenetic patterns. The new species we encountered in P. melinoptera had a close sister relationship with Ellipsomyxa adlardi , with both species part of a larger subclade within the Ellipsomyxa lineage. Despite this phylogenetic similarity, these species were morphologically distinct, and partial large subunit DNA sequences were only 93% similar to each other. A combination of the morphological characteristics and molecular data suggest that this is an undescribed species and we propose the name Ellipsomyxa gordeyi n. sp. [Display omitted] • New species Ellipsomyxa gordeyi n. sp. from Vietnamese waters. • Phylogenetic analysis of Ellipsomyxa species reveals inconsistent patterns. • Genetic analyses are critical for the identification of myxosporean species. [ABSTRACT FROM AUTHOR]

A strain of oogamous biflagellate green alga was isolated during a study on soil algal diversity in the Russian Far East (Sakhalin Region, Iturup Island) and examined using an integrative approach. Phylogenetic analyses, based on the SSU rDNA gene, resolved the new strain as a part of the RL clade (sensu Watanabe and Nakada) within Oogamochlamydinia (Volvocales, Chlorophyceae). The strain was similar to members of the genus Oogamochlamys (parietal and massive cup-shaped chloroplasts; two apical contractile vacuoles), but was, however, distinguished from them based on the size and shape of the mature vegetative cells, the flagellar length, the presence of only one pyrenoid in both the mature vegetative cells and the zoospores, the anterior nucleus position, and the spermatozoids’ shape. Although a concept of the genus Oogamochlamys has been compromised in recent phylogenetic analysis based on the SSU rDNA sequence data and its likely affinity to anisogamous Chlamydomonas allensworthii, we described the strain from Iturup Island as Oogamochlamys kurilensis sp. nov.

In mudflats, interactions and transfers of nutrients and secondary metabolites may drive ecosystems and biodiversity. Foraminifera have complex trophic strategies as they often rely on bacteria and eukaryotes or on potential symbionts for carbon and nitrogen resources. The capacity of these protists to use a wide range of adaptive mechanisms requires clarifying the relationships between them and their microbial associates. Here, we investigate the interactions of three foraminiferal species with nearby organisms in situ, by coupling molecular (cloning/Sanger and high‐throughput sequencing) and direct counting and morphological identification with microscopy. This coupling allows the identification of the organisms found in or around three foraminiferal species through molecular tools combined with a direct counting of foraminifera and diatoms present in situ through microscopy methods. Depending on foraminiferal species, and in addition to diatom biomass, diatom frustule shape, size and species are key factors driving the abundance and diversity of foraminifera in mudflat habitats. Three different trophic strategies were deduced for the foraminifera investigated in this study: Ammonia sp. T6 has an opportunistic strategy and is feeding on bacteria, nematoda, fungi, and diatoms when abundant; Elphidium oceanense is feeding mainly on diatoms, mixed with other preys when they are less abundant; and Haynesina germanica is feeding almost solely on medium‐large pennate diatoms. Although there are limitations due to the lack of species coverage in DNA sequence databases and to the difficulty to compare morphological and molecular data, this study highlights the relevance of combining molecular with morphological tools to study trophic interactions and microbiome communities of protists at the single‐cell scale. [ABSTRACT FROM AUTHOR]

Molecular data were used to revise the diversity of the genus Cryptomonas in Russia, using samples collected across nine geographic regions within Russia from 2015–2019. Several molecular markers were used: nuclear SSU, LSU and ITS2 rDNA, and plastid psbA. In total, 24 species of the genus Cryptomonas were identified in the country's fresh waters based on 122 different strains. Six new species were identified and are described here (Cryptomonas matvienkoae sp. nov., C. furtiva sp. nov., C. paludosa sp. nov., C. ursina sp. nov., C. kisselevii sp. nov. and C. meshchorana sp. nov.), and three taxa are emended (Cryptomonas skujae, C. platyuris and C. obovata). These new and emended species group in clades with the previously described species or represent new lineages on the phylogenetic tree. Seven morphospecies, previously reported in Russia, are confirmed by molecular methods, and two unidentified taxa are also reported. HIGHLIGHTS Molecular investigations of the genus Cryptomonas in Russia revealed 24 species. Descriptions of three species were emended. Six species new to science were described. [ABSTRACT FROM AUTHOR]

This study aimed to detect the occurrence of infection by Leishmania spp.in bats from 34 municipalities of Rio Grande do Sul state (RS; southern Brazil) from 2016 to 2021. A total of 109 bats were provided by the Centro Estadual de Vigilância em Saúde of RS, including six species belonged to Molossidae family, six to Vespertilionidae family, and two to Phyllostomidae family. Leishmania spp. was identified using the nested-PCR method by amplifying the SSU rDNA ribosomal subunit gene into four organ pools: (1) the liver, spleen, and lymph node; (2) heart and lungs; (3) skin; and (4) bone marrow of each bat. Three (3/109, 2.7%) animals tested positive for Leishmania spp. The respective PCR-positive organs came from pools 1 and 3. Two bats (Tadarida brasiliensis) were from the municipality of Canoas, and sequences analysis confirms the species identification as Leishmania infantum. In the third bat (Molossus molossus), from Rio Grande, it was not possible to determine the protozoa species, being considered Leishmania spp. Our results indicate that bats can participate in the biological cycle of Leishmania spp. and perform as host, reservoir, and/or source of infection of the protozoa in different areas of RS. More studies will be needed to elucidate the role of these Chiropteras in the circulation of Leishmania spp. This is the first study reporting the occurrence of Leishmania spp. in bats in Rio Grande do Sul state, southern Brazil. [ABSTRACT FROM AUTHOR]

During a survey of myxosporean parasites of freshwater fishes in northern Vietnam, myxospores resembling those of the genus Myxobolus (Myxosporea: Myxobolidae) were found in the trunk muscle of 6 out of 35 specimens (17.14%) of wild goldfish Carassius auratus (Cypriniformes: Cyprinidae). The mature spores were 12.0 ± 0.4 (11.4 − 12.6) µm long, 8.5 ± 0.2 (7.9 − 9.0) µm wide and 6.1 ± 0.2 (5.8 − 6.3) µm thick, containing two pyriform-shaped polar capsules unequal in size. The larger polar capsule was 7.6 ± 0.3 (7.1 − 8.4) µm long and 3.5 ± 0.1 (3.3 − 3.8) µm wide, and the smaller polar capsule was 6.2 ± 0.3 (5.5 − 6.7) µm long and 2.9 ± 0.2 (2.6 − 3.4) µm wide. Each polar capsule contained a polar filament with 3–5 coils. A phylogenetic analysis based on the small subunit rDNA (SSU rDNA) sequence revealed that this Myxobolus species forms a distinct branch in the phylogenetic tree sister to Myxobolus artus and Myxobolus cyprini, with DNA sequence similarity at 97.6% to M. artus and 97.5% to M. cyprini. A combination of the morphological characteristics and molecular data suggest that this is an undescribed species, and we propose the name Myxobolus hoabinhensis n. sp. [ABSTRACT FROM AUTHOR]

A new marine diatom species, Auricula weizhouensis sp. nov., was isolated from Weizhou Island, Guangxi, China, and the morphology was examined in detail. The frustule was symmetrical and quadrate, with four rounded angles. The valve was longitudinally reniform. The vegetative cells of A. weizhouensis were 28.9–35.0 μm in length and 22.2–28.9 μm in width. The mature cingulum was composed of five to six open bands. A large plate-like chloroplast was observed on the ventral side of the girdle. There were 5–7 poroids per 1 μm in a row along the median line. The number of radiate and biforked striae was 15–19 per 10 μm on the ventral margin and 21–31 per 10 μm on the dorsal margin. Striae were biseriate with two rows of areolae (12–14 areolae per 1 μm). Both sides of the double-sigmoid raphe canal had a longitudinal costa. Approximately 21–31 fibulae per 10 μm were arrayed in a row on each longitudinal costa. More importantly, A. weizhouensis and Auricula densestriata could be distinguished from other Auricula species by their characteristic concave ventral margin, and the ventral margin of A. weizhouensis was approximately straight in the middle, whereas that of A. densestriata was inflected. In addition, molecular data from partial SSU rDNA sequences showed that A. weizhouensis (strain WZ-1704-E8) belonged to the genus Auricula, with Auricula complexa (KX120684) as the nearest neighbour (4.58% p-distance). Therefore, both morphological and phylogenetic analyses supported A. weizhouensis as a new species. [ABSTRACT FROM AUTHOR]

Parasitological examination of the commercially important pelagic fish Sardinella aurita Valenciennes, 1847 (Clupeidae) from the Eastern coast of Algeria revealed xenomas in the peritoneal cavity, suggesting a microsporidian infection. The prevalence of the disease was approximately 30% on average, higher in smaller individuals and showing significant seasonal variation. The xenomas contained numerous ellipsoidal spores, surrounded by a dense layer of connective tissue. Spore sizes were 6.10 ± 0.38 µm length and 3.54 ± 0.43 µm width. Ultrastructural examination by transmission electron microscopy showed various development stages of the parasite, including meronts, sporonts, sporoblasts and mature spores. The internal organization of the mature spores, with a single nucleus, prominent posterior vacuole, a lamellar polaroplast and an isofilar polar tube arranged in a single row, was typical of the genus Glugea. The DNA sequence of the small subunit ribosomal RNA gene confirmed that this parasite belongs to the genus Glugea. Genetic and morphologic comparison with G. sardinellensis, a species previously described in the same host from Tunisia shows many similarities, although some molecular and morphometric inconsistencies precluded the unambiguous assignment of our samples to G. sardinellensis. At the same time, we do not find sufficient grounds to erect a new taxon for our parasite. We discuss the implications of our findings for the current state of the systematics of Glugea. [ABSTRACT FROM AUTHOR]

Abstract In mudflats, interactions and transfers of nutrients and secondary metabolites may drive ecosystems and biodiversity. Foraminifera have complex trophic strategies as they often rely on bacteria and eukaryotes or on potential symbionts for carbon and nitrogen resources. The capacity of these protists to use a wide range of adaptive mechanisms requires clarifying the relationships between them and their microbial associates. Here, we investigate the interactions of three foraminiferal species with nearby organisms in situ, by coupling molecular (cloning/Sanger and high‐throughput sequencing) and direct counting and morphological identification with microscopy. This coupling allows the identification of the organisms found in or around three foraminiferal species through molecular tools combined with a direct counting of foraminifera and diatoms present in situ through microscopy methods. Depending on foraminiferal species, and in addition to diatom biomass, diatom frustule shape, size and species are key factors driving the abundance and diversity of foraminifera in mudflat habitats. Three different trophic strategies were deduced for the foraminifera investigated in this study: Ammonia sp. T6 has an opportunistic strategy and is feeding on bacteria, nematoda, fungi, and diatoms when abundant; Elphidium oceanense is feeding mainly on diatoms, mixed with other preys when they are less abundant; and Haynesina germanica is feeding almost solely on medium‐large pennate diatoms. Although there are limitations due to the lack of species coverage in DNA sequence databases and to the difficulty to compare morphological and molecular data, this study highlights the relevance of combining molecular with morphological tools to study trophic interactions and microbiome communities of protists at the single‐cell scale.

Peritrich ciliates are a species-rich group of sessile unicellular eukaryotes, which can be found in various aquatic habitats from all over the world. It is well accepted that there are still many ciliates to be uncovered. During a survey on ciliate biodiversity in the coastal waters of China, three solitary peritrich species were identified as members of the genus Pseudovorticella Foissner & Schiffmann, 1975, including two new species and a rare one. Pseudovorticella zhejiangensis sp. n. differs from its congeners mainly by having a conical-shaped zooid, conspicuous pellicular blisters, one ventral and one dorsal contractile vacuoles, and an infundibular polykinety 3 with three rows of nearly equal length but different beginning positions. Pseudovorticella dalianensis sp. n. can be defined mainly by an obovoid-shaped zooid, one ventral contractile vacuole, and a three-rowed infundibular polykinety 3 with the middle row being the longest. The rare species, Pseudovorticella verrucosa (Dons, 1915) Sun et al., 2009, was redescribed. The small subunit (SSU) rDNA sequences of these three species were sequenced for the first time, the phylogeny of Pseudovorticella species was analyzed, and the results verified the non-monophyly of this genus. This study demonstrates that the morphologic and gene barcoding data are the optimum combination to disclose the biodiversity of ciliates.

The subclass Cyrtophoria are a group of morphologically specialized ciliates which mainly inhabit soil, freshwater, brackish water, and marine environments. In this study, we revise more than 50 publications on the taxonomy, phylogeny, and ecology of cyrtophorian ciliates in China since the first publication in 1925, most of which were carried out in coastal areas. The research history can be divided into three periods: the early stage, the Tibet stage, and the molecular stage. To date, 103 morpho-species (147 isolates) have been formally recorded in China, with ciliature patterns described for 82 of them. A species checklist and an illustrated identification key to the genera are provided. A total of 100 small subunit rDNA sequences have been obtained for 74 taxonomic hits (lowest taxonomic rank to species or genus). These sequences are used for the study of molecular phylogeny. Based on these morphological data and molecular phylogeny analyses, we synthesize the understanding of the phylogeny of cyrtophorian ciliates. We hypothesize that the key evolutionary event of cyrtophorian ciliates lies in the separation of the stomatogenesis zone (postoral kineties) from the left kineties, namely, the formation of an independent "sexual organelle". We, furthermore, briefly summarize the ecological features of cyrtophorian ciliates and provide a comprehensive bibliography of related research from China. Finally, we give an outlook on the future research directions of these taxa. [ABSTRACT FROM AUTHOR]

Thelohanellus nikolskii, Achmerov, 1955 is a well-known myxozoan parasite of the common carp (Cyprinus carpio L.). Infection regularly manifests in numerous macroscopic cysts on the fins of two to three month-old pond-cultured carp fingerlings in July and August. However, a Thelohanellus infection is also common on the scales of two to three year-old common carp in ponds and natural waters in May and June. Based on myxospore morphology and tissue specificity, infection at both sites seems to be caused by the same species, namely T. nikolskii. This presumption was tested with molecular biological methods: SSU rDNA sequences of myxospores from fins of fingerlings and scales of older common carp were analysed and compared with each other and with related species available in GenBank. Sequence data revealed that the spores from the fins and scales represent the same species, T. nikolskii. Our study revealed a dichotomy in both infection site and time in T. nikolskii-infections: the fins of young carp are infected in Summer and Autumn, whereas the scales of older carp are infected in Spring. Myxosporean development of the species is well studied, little is known, however about the actinosporean stage of T. nikolskii. A previous experimental study suggests that aurantiactinomyxon actinospores of this species develop in Tubifex tubifex, Müller, 1774. The description included spore morphology but no genetic sequence data (Székely et al., 1998). We examined >9000 oligochaetes from Lake Balaton and Kis-Balaton Water Reservoire searching for the intraoligochaete developmental stage of myxozoans. Five oligochaete species were examined, Isochaetides michaelseni Lastochin, 1936, Branchiura sowerbyi Beddard, 1892, Nais sp., Müller, 1774, Dero sp. Müller, 1774 and Aelosoma sp. Ehrenberg, 1828. Morphometrics and SSU rDNA sequences were obtained for the released actinospores. Among them, from a single Nais sp., the sequence of an aurantiactinomyxon isolate corresponded to the myxospore sequences of T. nikolskii.

During a parasitological survey of goldfish Carassius auratus (Linnaeus, 1758) in China, two myxosporeans were collected in the present study including a Thelohanellus species and a Myxobolus species. To identified the two myxosporeans, a morphological, histological and molecular study was performed. The Thelohanellus species was characterized by round, white plasmodia in fins of goldfish. Compared with all described Thelohanellus species, spore morphology of the Thelohanellus species in the present study was distinct from them. BLAST search showed that SSU rDNA sequence of this Thelohanellus species did not match any sequence in GenBank database. Phylogenetically, the Thelohanellus species obtained in the present study was sister to Thelohanellus nikolskii Achmerov, 1955. So, the present Thelohanellus species was identified as a novel species and named Thelohanellus pseudonikolskii n. sp. The Myxobolus species was characterized by a number of round or irregularly shaped, white plasmodia in gills of goldfish. When compared with all reported Myxobolus species, spore morphology of the present Myxobolus species was most similar to Myxobolus koi Kudo, 1920. Histological analysis showed that plasmodia of this Myxobolus species simultaneously developed in stratified epithelium of filament and in lamellae, which was same to M. koi. Moreover, BLAST search showed that SSU rDNA sequence of the present Myxobolus species was identical to M. koi. Thus, the morphological, histological and molecular analysis demonstrated that the present Myxobolus species was conspecific with M. koi. Due to M. koi consistently described from gills of common carp Cyprinus carpio Linnaeus, 1758 and koi carp C. carpio in the previous researches, M. koi was first found to infect gills of goldfish in the present study. Considering koi carp and goldfish both as ornamental fish frequently cultured together in China, the possible host shift of M. koi from koi carp to goldfish is of interest for further investigation.

The morphology and morphogenesis of Lamtostyla paravitiphila nov. spec. , a novel soil hypotrichous ciliate collected from eastern China, were investigated based on live observations and protargol-stained specimens. The new species is morphologically characterized as follows: seven to twelve macronuclear nodules, cortical granules absent, 19–26 adoral membranelles, three or four frontoventral cirri, the amphisiellid median cirral row extends to about mid-body and composed of 12–18 cirri, two or three transverse cirri, 27–39 left and 30–41 right marginal cirri, three almost bipolar dorsal kineties. Morphogenetically, it is characterized by the initial formation of six frontal-ventral-transverse cirral anlagen as primary primordia. Notably, the amphisiellid median cirral row and the posterior frontoventral cirrus (or cirri) contribute to the development of the frontal-ventral-transverse cirral anlagen, while the buccal cirrus may not participate in this process. Phylogenetic analyses based on small subunit ribosomal DNA sequence data indicate that the Lamtostyla species with available molecular data do not form a monophyletic group. [ABSTRACT FROM AUTHOR]

Summary: Cryptaphelenchus recticaudatus n. sp. is described and illustrated in Pinus elliottii from the USA. The new species is characterised by the female body 310-431 μ m long with distinctly annulated cuticle, lateral fields with four lines, lip region separated from the body by a shallow depression, delicate stylet with small knobs, post-vulval uterine sac short, and rectum and anus invisible. Males are 228-314 μ m long, spicules 9.8-12.4 μ m long with a well-developed and broad condylus, and seven caudal papillae arranged as a single (P1) and pair (P2) of precloacal papillae plus two pairs of postcloacal papillae. Based upon the general female morphology, the new species most closely resembles C. baujardi and C. iranicus. The morphological differences with the aforementioned species and other species of the genus are discussed. The phylogenetic analyses based on small (SSU) and large subunit (LSU) D2-D3 expansion segments of ribosomal DNA of different individuals of the new species revealed that the new species fell into the Cryptaphelenchus clade in both SSU and LSU trees. The monophyly of the genus was retained after adding newly generated sequences of the new species. [ABSTRACT FROM AUTHOR]

Sphaeromyxa azevedoi n. sp. is described from the gall bladder of the goby Gobioides grahamae (Gobiidae) captured on the Paracauari River in Salvaterra, on Marajó Island, northern Brazil. A total of 50 G. grahamae specimens were analysed, and 15 (30%) were parasitised by the plasmodia and myxospore of Sphaeromyxa azevedoi n. sp. Large plasmodia were observed floating in the bile. These plasmodia were flat, rounded, oval or elongated, and of varying sizes. The mature myxospores, found singly or in pairs, were 27.1 ± 2.7 (20.5–30.1) μm Length and 3.8 ± 0.2 (3.5–4.4) μm Width in the valvular view. The myxospore has two polar capsules of equal size, 8.1 ± 0.6 (7.4–9.4) μm in length and 2.9 ± 0.2 (2.3–3.3) μm in width. A polar tubule was observed in each capsule, arranged perpendicularly to the principal axis, with three or four coils. The histological analysis showed that the plasmodia and myxospore are located in the lumen of the gall bladder, arranged in pairs, and the epithelium of the gall bladder presented multifocal necrosis. The SSU rDNA of Sphaeromyxa azevedoi n. sp. clusters in the 'balbianii' group of the Sphaeromyxa clade. The morphological characteristics and molecular phylogeny of Sphaeromyxa azevedoi n. sp. support its classification as a new species of the genus Sphaeromyxa, which represents an important advancement in the understanding of the diversity of the myxozoan parasite fauna of Brazilian fishes, especially considering that the new species may be detrimental to the host, a commercially important Brazilian fish species. [ABSTRACT FROM AUTHOR]

In this study, the cryptomonads of the northern territories of Russia were explored. Four strains were isolated from the different acidic habitats in the Middle Urals and the North of the European part of Russia. Cells of these strains are flattened in the dorsoventral plane, have an asymmetrical outline and are similar in size and shape to Cryptomonas erosa. Phylogenetic relationships inferred using maximum likelihood and Bayesian interference from datasets of nuclear-encoded SSU, LSU, ITS2 rDNA and psbA cpDNA show that the strains form one clade, which was divided into three subclades with high statistical support. One subclade was attributed to Cryptomonas erosa. Two other subclades represent species new to science. Comparison of ITS2 rRNA secondary structures with the compensatory base changes (CBC) approach confirmed the separation between C. erosa and the two new species, C. macilenta sp. nov. and C. parmana sp. nov. Comparison of nuclear V9 SSU and ITS1 rDNA sequences of two new species with metabarcoding data from 218 lakes in Europe showed that C. macilenta and C. parmana have not previously been recorded in Europe. [ABSTRACT FROM AUTHOR]

Because the original description of Bakuella (Bakuella) marina , type of the genus, is only based on protargol-impregnated specimens, one of the important living features, namely, the presence/absence of cortical granules, remains unknown so far. In the present work, a detailed investigation of a Chinese population of B. (Bakuella) marina is carried out using the integrated approaches, and the live morphology, ontogenesis, and molecular information of B. (Bakuella) marina are presented for the first time. The infraciliature of this population corresponds perfectly with that of the original description. The in vivo observation indicates that B. (Bakuella) marina possesses colorless cortical granules. The most prominent morphogenetic feature of B. (Bakuella) marina is that the parental adoral zone of membranelles is completely replaced by the newly formed one of the proters. Molecular phylogenetic analysis based on a small subunit ribosomal gene (SSU rDNA) shows that five Bakuella species are clustered with the species from other six Urostylid genera, namely, Anteholosticha , Apobakuella , Diaxonella , Holosticha , Neobakuella , and Urostyla. The monophyletic probabilities of the family Bakuellidae, genus Bakuella , subgenus B. (Bakuella) , and subgenus B. (Pseudobakuella) are rejected by the approximately unbiased test. This study further shows that the family Bakuellidae, genus Bakuella , and subgenus B. (Bakuella) are all nonmonophyletic groups. In order to establish a reasonable classification system, information on molecular and morphogenesis of more Bakuellids and its related species is urgently needed. [ABSTRACT FROM AUTHOR]

A new myxozoan species, Ceratomyxa binhthuanensis n. sp. (Myxosporea: Ceratomyxidae), was found in the gall bladder of blacktip grouper Epinephelus fasciatus (Perciformes: Serranidae) in the East Sea of Vietnam. Myxospores were observed floating free in the gall bladder of 3 out of 20 fish examined (15%). Mature myxospores were elongate and slightly crescent-shaped and measured 12.2 ± 1.3 (10.8–16.0) μm in thickness and 5.8 ± 0.6 (4.8–6.9) μm in length, with two smooth equal shell valves. The two polar capsules were spherical and equal in size, measuring 2.6 ± 0.3 (2.3–2.9) μm in diameter. The posterior angle was slightly concave, 153.7° ± 5.6° (148.9°–166.0°). Molecular analysis of SSU rDNA sequence showed that Ceratomyxa binhthuanensis n. sp. differs from other Ceratomyxa spp. available in GenBank. Phylogenetic analysis indicated that C. binhthuanensis n. sp. was closely related to three species, Ceratomyxa nolani, Ceratomyxa yokoyamai, and Ceratomyxa cutmorei, which also infect fish hosts of the genus Epinephelus. [ABSTRACT FROM AUTHOR]