New Species Of Myxobolus Research Articles

Histopathological and phylogenetic description of an Amazonian cnidaria microparasite Myxobolus rousseauxii n. sp. infecting the gill arches of Brachyplatystoma rousseauxii (Siluriformes)

From genus Myxobolus, cnidarians of Myxozoa class, is well known for infecting economically important fish species and, as result, relevant losses in aquaculture production can be observed. They are present in a big range of fish in its natural habitat, including the migratory Brachyplatystoma rousseauxii catfish. This study aimed is to develop an integrative characterization of a new species of Myxobolus, located in B. rousseauxii's gills. To accomplish this, 30 specimens of B. rousseauxii catfish were collected from Mosqueiro Island in Pará, Brazil; necropsied and analyzed for morphology, histology and molecular characteristics. Cysts with conjunctival capsule development made up of fibroblasts were observed at the gill arches; such proliferation caused bone tissue loss and cartilage compression. The cysts contained Myxobolus myxospores measuring 9.9 μm of length and 9.6 μm of width, whereas polar capsules were 5.4 μm long and 3.4 μm wide, with 8 to 9 coils of polar tubules. Phylogenetic analyses revealed that new species were included in a subclade alongside species from the same geographic location and infection site that infect Siluriformes fish. Morphological and molecular differences revealed that Myxobolus spp. parasite-host associations through histopathology supporting the designation of a new M. rousseauxii n. sp. species in B. rousseauxii, a commercially important fish.

New species of Myxobolus in potamodromous catfish from the eastern Amazon, Brazil

The mapará (Hypophthalmus marginatus) is a commercially important fish in the Brazilian Amazon and has been described as a host for numerous myxosporid species. The integrated taxonomy of a new species, Myxobolus mickeyii n. sp., discovered in the urinary bladder of H. marginatus, is undertaken in this study. In 105 specimens of H. marginatus, plasmodia and myxospores were observed in the urinary bladder fluid, the myxospores measuring 20.5 (19.6–21.3) μm in length and 14.0 (13.2–14.9) μm in width. The posterior valves of the spore body were thick, with valvulogenic nuclei, endoplasmic reticulum, and the presence of secretory vesicles. Two elliptical, rounded appendages attached to the valve, containing tubular filaments. The two polar capsules, symmetry, measuring 6.1 (5.9–6.3) μm in length and 4.4 (3.6–6.2) μm in width, with polar tubules of 3 to 5 turns. Phylogenetic analyses of the small subunit ribosomal RNA gene (SSU rDNA) sequencing revealed that M. mickeyii n. sp. is part of a Myxobolidae family clade with freshwater fish of the Siluriformes order, with a genetic distance of 19% to the nearest species. This work contributes to the wide diversity of myxozoans in this host, as other taxa have previously been reported infecting different tissues.

WITHDRAWN: Molecular identification of myxozoans and helminths in the black goby Gobius niger L. (Gobiiformes: Gobiidae) from the Finnish Archipelago, Baltic sea

Black gobies (Gobius niger) from the Finnish Archipelago, Baltic Sea, were screened for helminth and myxozoan infections in summer 2020. Helminths were identified morphologically and/or molecularly, myxozoan DNA was only detected during molecular screening. Altogether 30 novel sequences were generated and analysed using maximum likelihood estimation. Morphological and phylogenetic analyses based on SSU rDNA (myxozoans) and mitochondrial genes (helminths) revealed the presence of 10 species: two species of Myxozoa (a putative new species of Myxobolus and Tetracapsuloides bryosalmonae), and eight helminth species belonging to the Digenea (Diplostomum mergi Lineage 3), Cestoda (Bothriocephalus scorpii), Nematoda (Contracaecum rudolphii A, Cucullanus sp. and Hysterothylacium aduncum), and Acanthocephala (a putative new species of Corynosoma, Corynosoma semerme and Neoechinorhynchus sp.). Phylogenetic and comparative sequence analyses revealed that the putative new acanthocephalan species is closely related to C. neostrumosum in the Caspian Sea. Myxobolus sp. was resolved as closely related but distinct from a species described from freshwater fish in Lake Balaton, Hungary. In addition to these two putative new species, the black goby represents a new host record for four parasite species (Tetracapsuloides bryosalmonae, Diplostomum mergi Lineage 3, Contracaecum rudolphii A and Corynosoma semerme). The Finnish Archipelago is a novel locality record for four species (Myxobolus sp., Corynosoma sp., Diplostomum mergi Lineage 3 and Bothriocephalus scorpii).

Phylogeny and ultrastructure of Myxobolus rangeli n. sp. (Myxozoa, Bivalvulida), a histozoic parasite in Siluriformes fish from the Amazon region.

A new species of Myxobolus parasitizing the arterial bulb and cardiac musculature of the freshwater fish Pimelodus ornatus Kner, 1858, from the Arari river in the municipality of Cachoeira do Arari, island of Marajó, Pará, Brazil, was described. In the present study, the observed prevalence of myxozoan parasites in the heart tissue of the hosts was 20% (6/30). The myxozoans observed had mature biconvex spores, slightly rounded, an anterior end with two pyriform polar capsules and a posterior end with very evident sporoplasm, measuring 8 ± 0.2 μmin length. The spore width was 5.8 ± 0.4 μm, with a thickness of 3.4 ± 0.2μm. The length of the polar capsules was 3.6 ± 0.3 μm and the width was 1.2 ± 0.2μm, with 6 to 7 turns of the polar filament. The divergences observed, regarding the morphometric and genetic structure of SSU rDNA, in relation to other Myxobolidae already described in the literature, confirm the description of the new species Myxobolus rangeli n. sp.

Two new species of Myxobolus (Myxozoa: Myxobolidae) infecting the gill and scales of the smallmouth bass, Micropterus dolomieu (Centrarchiformes: Centrarchidae) in the French Broad River Basin, North Carolina

Two new species of Myxobolus Bütschli, 1882 (Bivalvulida: Myxobolidae) are described from the gill and scales of smallmouth bass (Micropterus dolomieu Lacepède, 1802 [Centrarchiformes: Centrarchidae]) from the Watauga River, French Broad River Basin, North Carolina, United States. Myxobolus intralamina n. sp. infects the lumen of the lamellar arterioles and Myxobolus infrabractea n. sp. infects the inner surface of the scale. They differ from all congeners by a combination of myxospore dimensions, polar tubule coil count, and the presence or absence of an iodinophilic vacuole in the sporoplasm and an intercapsular process. A phylogenetic analysis of the small subunit ribosomal DNA (SSU rDNA) recovered M. intralamina n. sp. sister to Myxobolus lepomis and Myxobolus branchiarum and M. infrabractea n. sp. sister to Myxobolus micropterii in a clade composed of five Myxobolus spp. infecting centrarchids and Henneguya spp. (Myxobolidae) infecting percids. Histological sections of infected gill revealed intra-lamellar plasmodia of M. intralamina n. sp. within the lumen of the lamellar arterioles and plasmodia of M. infrabractea n. sp. developing beneath the scales. These new species comprise the first species of Myxobolus reported from a black bass (Micropterus Lacepède, 1802) in the Southeast United States.

Taxonomy and Systematics of Two New Species of Myxobolus (Cnidaria: Myxobolidae) Parasitizing the Gills of Mugil curema (Mugilidae) from the Brazilian Coast

We describe two new species of Myxobolus (Myxobolidae) found parasitizing Mugil curema from two locations in Brazil: Myxobolus curemae n. sp. from gill arch and rays and Myxobolus maceioensis n. sp. from gill lamellae. We based the descriptions on myxospore morphology, histology, and small-subunit ribosomal DNA sequences. Myxospores of the two new species had similar morphology and morphometry but differed in spore body width and length, and ssrDNA sequences differed by 10.5%. These data supported the diagnosis of the parasites as distinct and novel species. The phylogenetic analysis showed a subclade formed by species that parasitize Mugiliformes, with M. maceioensis n. sp. as a sister species of Myxobolus episquamalis and Myxobolus bizerti, while there is a group of six species that are sister related to M. curemae n. sp. Our analysis was consistent with previous studies suggesting that orders of the hosts are strongly correlated with phylogenetic signals in the Myxobolidae. Myxobolus curemae n. sp. and M. maceioensis n. sp. are new species identified parasitizing M. curema.

Two new species of Myxobolus Bütschli, 1882 (Cnidaria: Bivalvulida: Myxobolidae) infecting the gill of the black redhorse, Moxostoma duquesnei (Lesueur) (Cypriniformes: Catostomidae) in the Little Tennessee River Basin, North Carolina.

Two new species of Myxobolus Bütschli, 1882 (Bivalvulida: Myxobolidae) are described from the gill of the black redhorse (Moxostoma duquesnei [Leueur][Cypriniformes: Catostomidae]) from the Little Tennessee River Basin, North Carolina, United States. Myxobolus branchiofilum n. sp. infects lumen of the lamellar arterioles and Myxobolus branchiopecten n. sp. infects the bone and cartilage at the tip of the gill rakers. They differ from all congeners by a combination of myxospore dimensions and the presence or absence of an iodinophilic vacuole in the sporoplasm, mucous envelope, intercapsular process, and sutural markings. A phylogenetic analysis of the small subunit ribosomal DNA recovered M. branchiopectin sister to Myxobolus sp. (AF378343) in a clade composed of 6 species of Myxobolus, which infect predominately cypriniform intermediate hosts. Myxobolus branchiofilum was recovered sister to Myxobolus ictiobus Rosser, Griffin, Quiniou, Alberson, Woodyard, Mischker, Greenway, Wise & Pote, 2016 in a clade composed of 8 species of Myxobolus, which predominately infect catostomid intermediate hosts. Histological sections of infected gill revealed intra-lamellar plasmodia of M. branchiofilum in the lumen of the lamellar arterioles and foci of M. branchiopecten developing in the bone and cartilage of the gill raker tip. These are the first myxozoans reported from the black redhorse. Given that these two new species are morphologically congeneric but recovered in distantly related clades, we discuss the persistent issue of myxobolid genera paraphyly/polyphyly.

Two new species of Myxobolus (Cnidaria: Myxosporea) infecting freshwater fishes of Ranjit Sagar Wetland, Punjab, India

Two novel myxosporeans have been identified during the present study namely, Myxobolus upmae sp. nov. infecting gills of Hypophthalmichthys nobilis and Myxobolus hardevi sp. nov. infecting gills of Labeo bata inhabiting Ranjit Sagar Wetland, Punjab (India). The identification was done on the basis of morphological and molecular attributes of the myxospores. Myxospores of both the species possessed distinct morphological and morphometric characteristics, hence, validated as new species. Prevalence of infection was found to be 31.25% and 24% in M. upmae and M. hardevi, respectively. The intensity of infection or the mean abundance was determined by the gill plasmodial index (GPI) and was found to be 3 in M. upmae (heavy infection) and 1 in M. hardevi (light infection). Histopathological analysis of both the myxosporeans showed necrosis, hypertrophy, lamellar fusion and the cavity of each plasmodium was filled with numerous fully mature myxospores. The phylogenetic analysis of M. upmae sp. nov. showed maximum homogeneity with M. catlae (KM029967) infecting gills of Catla catla from India followed by M. dujardini (DQ439804) infecting gills of Leuciscus cephalus from Hungary and M. alvarezae (FJ716096) infecting gills of Aspius aspius from Hungary. The phylogenetic tree obtained by Maximum-Likelihood showed the paraphyletic nature of M. upmae sp. nov. with other myxosporean species.

Myxozoan hidden diversity: the case of Myxobolus pseudodispar Gorbunova, 1936.

Myxobolus pseudodispar Gorbunova, 1936 (Myxozoa) was originally described as a parasite of common roach, Rutilus rutilus (Linnaeus), with developing stages in muscles and spores disseminated in macrophage centres of different organs and tissues. Later, this parasite was described from several other cyprinids, but with relatively large intraspecific differences based on SSU rDNA gene sequences. Within our long-term study on myxozoan biodiversity, we performed a broad microscopic and molecular screening of various freshwater fish species (over 450 specimens, 36 species) from different localities. We investigated the cryptic species status of M. pseudodispar. Our analysis revealed four new unique SSU rDNA sequences of M. pseudodispar as well as an infection in new fish host species. Myxobolus pseudodispar sequence analysis showed clear phylogenetic grouping according to fish host criterion forming 13 well-recognised clades. Using 1% SSU rDNA-based genetic distance criterion, at least ten new species of Myxobolus Bütschli, 1882 may be recognised in the group of M. pseudodispar sequences. Our analysis showed the paraphyletic character of M. pseudodispar sequences and the statistical tests rejected hypothetical tree topology with the monophyletic status of the M. pseudodispar group. Myxobolus pseudodispar represents a species complex and it is a typical example of myxozoan hidden diversity phenomenon confirming myxozoans as an evolutionary very successful group of parasites with a great ability to adapt to a new hosts with subsequent speciation events.

Description of new myxozoan parasite Myxobolus awadhii sp. nov from the gills of freshwater catfish Clarias batrachus Linn.

Parasitic infestations are one of the major problems in freshwater fish production. Clarias batrachus Linnaeus, 1758 (Clariidae) is a commercially important native catfish mainly used for food as it has very high iron content and other minerals. Unfortunately, it is difficult to breed in captivity and is highly prone to parasitic infections particularly the Myxobolus sp. The present article discusses a new species of Myxobolus identified as Myxobolus awadhii from the gills of C. batrachus. Plasmodia were found on the gill filaments with the intensity of infection to be moderate as indicated by gill plasmodial index (GPI = 6). The mature myxospores were oval to ellipsoidal in shape measuring 8.82-11.68 (10.57 ± 0.50) × 5.76-7.37 (6.70 ± 0.36) μm in size. The present species was compared with species found from the same host and other resembling species as M. acanthorhodi, M. bhadurius, M. bilineatum, M. chrysichthyi. Present article deals with morphological and morphometric description of M. awadhii sp. nov. Morphological comparisons of the mature myxospores were done with the similar myxospores and species reported earlier from C. batrachus.

Morphotaxonomical description of three new species of Myxobolus Bütschli, 1882 (Myxozoa: Myxosporea: Bivalvulida) from edible freshwater fishes of West Bengal, India.

Three new species of Myxobolus are described from the mucous membrane around gill lamellae of carps of West Bengal. The new species have been named as M. muralidharani sp. n., M. nilimae sp. n. from Labeo rohita, and M. harpreetae sp. n. from Labeo bata respectively. Spores of M. muralidharani sp. n. measured 13.84±0.049 (13-14)×4.95-6 (5.35)µm, with two elongated equal sized polar capsules. Spores of M. nilimae sp. n. measured 15.9-17.1 (16.65) µm×6.2-7.5 (6.9)µm, with two equal petal shaped polar capsules, 9.0-11 (10.4)µm×3-3.5 (3.16)µm. In contrast to aforementioned two new species, M. harpreetae sp. n. had two unequal polar capsules, 8.7-9.2 (9.149)µm×2.9-4.0 (3.45)µm and 7.6-8.3 (7.94)µm×2.8-3.3 (2.9)µm in each spore, 11.4-13.8 (13.2)µm×4.9-7.8 (6.51)µm.

Description of three new species of the genus Myxobolus infecting carp fishes of India.

Myxobolus Bütschli, 1882 (Myxozoa, Myxosporea, Bivalvulida, Myxobolidae) is an important parasitic protozoan of freshwater fishes reported from almost all over the world. The severity of infection may lead to mortality of the host fish. The present paper deals with the description of three new species of Myxobolus Bütschli, 1882, Myxobolus sonarpurensis sp. nov., Myxobolus elongatum sp. nov. and Myxobolus petalum sp. nov. from a freshwater minor carp Labeo bata (Hamilton, 1822) and major carp Labeo rohita (Hamilton, 1822) respectively from West Bengal, India. Spores of Myxobolus sonarpurensis sp. nov. measures 12.16µm×6.74µm, with two elongated unequal sized polar capsules measuring, 8.84µm×3.019µm and 7.71µm×3.12µm. Spores of Myxobolus elongatum sp. nov. are 16.23µm×7.9µm with two equal polar capsules 8.896µm×3.468µm and 6.51µm×3.46µm. In comparison to aforementioned two new species, Myxoboluspetalum sp. nov. have two equal polar capsules, 7.905µm×2.975µm (2.9µm) in each spore, 12.07µm×5.95µm.

Three new species of Myxobolus Bütschli, 1882 (Myxozoa: Myxobolidae) infecting the common nase Chondrostoma nasus (L.) in the River Danube.

The common nase Chondrostoma nasus (L.) is a frequent cyprinid fish in the River Danube. In a survey on its infection with myxosporeans, eight different Myxobolus spp. spore types were found in the gills, swim bladder, fins and intestinal wall. Of these, spore types representing three species were studied in detail by morphological and molecular methods. Based on the differences in 18S rDNA sequences, two new species of Myxobolus Bütschli, 1882 from the gills and one from the swim bladder are described: M. arrabonensis n. sp., M. szentendrensis n. sp. and M. paksensis n. sp. The new species resembled M. muelleri Bütschli, 1882, M. intimus Zaika, 1965 and M. cycloides Gurley, 1893, all parasitic in leuciscine cyprinids, in spore size and location in the host, but exhibited differences in partial 18S rDNA sequences as follows: M. arrabonensis - M. muelleri (1.4%), M. szentendrensis - M. intimus (2.8%), M. paksensis - M. cycloides (2.4%). Based on the significant differences in rDNA sequences, the three forms are considered to represent new, hitherto undescribed species in spite of their morphological similarities to some Myxobolus spp. forming spores in identical locations in genetically closely related cyprinids of the subfamily Leuciscinae.

Two new Myxobolus spp. (Myxozoa: Myxobolidae) from white bream, Blicca bjoerkna (Linnaeus, 1758) developing in basifilamental location of gills

Two new Myxobolus species, M. bjoerknae sp. n. and M. lamellobasis sp. n. have been described from the gills of white bream, Blicca bjoerkna . Plasmodia of M. bjoerknae sp. n. developed in the connective tissue inside the cartilaginous gill arch, while plasmodia of M. lamellobasis sp. n. seem to start their development in the multilayered epithelium between two lamellae close to the base of gill filaments. Then they may bulge out of the interlamellar space fused to a large bulk locating at the base of filaments. The large, ellipsoidal spores of M. bjoerknae sp. n. 17.4 × 13.1 µm in size, resembled the spores of other species developing in the gill arch (e.g. M. fundamentalis , M. gayerae , and M. pfeifferi ), but differed from them in its 18S rDNA sequence. Roundish spores of M. lamellobasis sp. n. with a size of 11.1 × 8.6 µm resembled the spores of M. impressus developing interlamellarly and the spores of M. rotundus, M. parviformis , and M. muellericus having intralamellar localization. However, the detected genetic difference clearly distinguished it from the other species developing in similar tissue location. The phylogenetic location of the two newly described species seems to correlate both with spore shape and fish host species.

Description of Two New Gill Myxozoans from Smallmouth (Micropterus dolomieu) and Largemouth (Micropterus salmoides) Bass

Two previously undescribed species of myxozoan parasites were observed in the gills of bass inhabiting the Potomac and James River basins. They are described using morphological characteristics and small-subunit (SSU) rDNA gene sequences. Both were taxonomically identified as new species of Myxobolus; Myxobolus branchiarum n. sp. was found exclusively in smallmouth bass, and Myxobolus micropterii n. sp. was found in largemouth and smallmouth bass. Small, spherical, white plasmodia of M. branchiarum from smallmouth bass were observed grossly in the gills; these plasmodia had an average length of 320.3 µm and width of 246.1 µm. The development of the plasmodia is intralamellar in the secondary lamellae of the gills. Mature spores were pyriform in shape with a length of 12.8 ± 1.4 (8.1-15.1) µm and width of 6.9 ± 1.1 (4.0-9.0) µm. Analysis of SSU rDNA identified M. branchiarum in a sister-group to 3 species of Henneguya , although morphologically caudal appendages were absent. Myxobolus micropterii observed in the gills of largemouth and smallmouth bass had larger, ovoid, cream-colored plasmodia with an average length of 568.1 µm and width of 148.1 µm. The cysts developed at the distal end of the gill filament within the primary lamellae. The mature spores were ovoid in shape with a length of 10.8 ± 0.7 (9.2-12.2) µm and width of 10.6 ± 0.6 (9.0-11.8) µm. SSU rDNA analysis placed M. micropterii in a sister group with Henneguya lobosa and Myxobolus oliveirai . The highest prevalence of M. branchiarum was observed in the gills of bass collected from the Cowpasture River (50.9%). Prevalence was 44.6% in bass from the Potomac River and only 4.3% in bass collected from the Shenandoah River. A seasonal study of M. branchiarum , which included both infected and uninfected smallmouth bass, determined that a significantly higher intensity was observed in the spring than in the summer (P < 0.001) or fall (P = 0.004). In an analysis excluding uninfected bass, a higher intensity was observed in the spring than in the summer (P = 0.001) or fall (P = 0.008). Prevalence and seasonal differences were not determined for M. micropterii .

Two new species of Myxobolus (Myxozoa: Myxosporea: Bivalvulida) infecting an Indian major carp and a cat fish in wetlands of Punjab, India

A survey of parasites of freshwater fishes in Kanjali and Harike wetlands of Punjab (India) revealed the presence of two new myxosporean species belonging to the genus Myxobolus Bütschli (Winter (ed): Protozoa, 1882). Spores of the first species, M. saugati sp. nov. parasitizing scales of Labeo rohita (Cypriniformis: Cyprinidae) vern. rohu are characterized in having 'spores measuring 8.3×6.6μm in size, oval to spherical in valvular view having rounded anterior and posterior ends; polar capsules are two, equal, measuring 4.0×2.4μm, pyriform with distinct neck at the anterior end; an intercapsular process is absent'. Spores of the second species, Myxobolus szekeli sp. nov. parasitizing internal wall of stomach of Wallago attu (Cypriniformis: Siluridae) vern. mulle are '8.7×4.1μm in size, elongately ovoidal in valvular view having tapering, bluntly pointed anterior end and rounded posterior end; polar capsules are two, equal, measuring 4.4×1.5μm, tubular with blunt anterior and rounded posterior ends; polar capsules converge anteriorly but are placed at a distance posteriorly and occupies nearly half of the spore body cavity; an intercapsular process is absent'.

Two new species of Myxobolus (Myxozoa: Myxosporea: Bivalvulida) infecting an Indian major carp in Ropar and Kanjali wetlands (Punjab)

In India, more than 104 species of Myxobolus are recorded infecting freshwater and marine fishes. During our study on the myxozoan parasites of fishes of Punjab wetlands, India, two new myxosporean species, Myxobolus ropari sp. nov. and Myxobolus kanjali sp. nov. were recorded from mucous membrane around gill lamellae and scales of Cirrhina mrigala (Ham.), respectively. Spores of the first species, M. ropari sp. nov. measure 12.58×4.5μm in size, elongately pyriform, slender in shape with a pointed anterior end and a rounded posterior end. Polar capsules are two, equal, elongately pyriform, measuring 4.96×1.50μm in size, placed posteriorly from the tip of the spore running parallel to each other. Spores of the second species, M. kanjali sp. nov. measure 9.5×7.7μm in size, spherical in shape with rounded anterior and posterior extremities. Polar capsules are two, equal, broadly pyriform with a blunt anterior and a rounded posterior end measuring 4.8×1.8μm in size. A prominent tubular structure originate from the anterior end of one of the polar capsule and extend backward beyond the margin of the spore body and run upwards to join the posterior end of the other polar capsule.

Two new species of Myxobolus (Myxozoa: Myxosporea: Bivalvulida) infecting Indian freshwater fishes in Punjab Wetlands (India)

A survey of parasites of freshwater fishes in Harike and Ropar Wetlands of Punjab (India) revealed the presence of two new myxosporean species belonging to the genus Myxobolus Butschli 1882. Spores of the first species, M. duodenalis sp. nov. parasitize the inner wall of the duodenum of Wallago attu (Bloch and Schneider) (Cypriniformis: Cyprinidae) vern. mulli are characterized by a broad, pyriform shape with a blunt anterior end and measures 9.0 × 3.20 μm. Spore valves are thin, smooth, and symmetrical with no parietal folds. There are two polar capsules, prominently unequal and pyriform in shape, with a narrow anterior end and a rounded posterior end. The larger polar capsule measures 4.70 × 1.76 μm and the smaller 2.76 × 1.06 μm. The larger polar capsule occupies more than half, while the smaller one occupies one third of the spore body cavity. An intercapsular process is absent. Spores of the second species, Myxobolus patialensis sp. nov. parasitize the caudal fin of Labeo rohita (Ham. 1822) (Cypriniformis: Cyprinidae) vern. rohu are pyriform in valvular view, measuring 11.28 × 6.67 μm. The two shell valves are asymmetrical and contain five parietal folds along the posterior end of the spore. Two anteriorly situated polar capsules, elongated and oval in shape are prominently unequal in size. The larger polar capsule measures 4.8 × 3.1 μm and smaller one 1.70 × 1.51 μm. The larger polar capsule lies obliquely to the spore axis and the smaller one is at the same level but pointing outward anteriolaterally. An intercapsular process is absent. This species is characterized by having a prominent ridge on the shell surface anteriolaterally on the side of the smaller polar capsule.

A new myxosporean species Myxobolus sclerii sp. nov. and one known species M. stomum Ali et al. 2003 from two Indian major carp fishes

The present communication deals with description of one new species of Myxobolus (Myxozoa: Myxosporea: Bivalvulida), M. sclerii sp. nov. infecting eye ball of Catla catla (Hamilton) and redescription of M. stomum infecting scales of Labeo rohita (Hamilton), two major carps of Kanjali and Ropar Wetlands respectively. Spores of M. sclerii sp. nov. measure 7.9-9.5(8.7±1.13)×4.3-5.7(5±0.98)μm in size. Parietal folds absent. Polar capsules two, equal and measuring 4-5.4(4.7±0.98)×1-2.6(1.8±1.31) μm in size. A rod-shaped medium-sized intercapsular process is present. Iodinophilous vacuole present measuring 2.19-4.13(3.16±1.37)μm in diameter. Spores of M. stomum Ali et al.2003 measure 9.8-10.3(10.0±0.35)×7.9-8.7(8.3±0.56)μm in size, with rounded anterior and posterior end. Spore valves smooth, symmetrical, thick measuring 0.88μm in thickness. Parietal folds absent. Two anteriorly situated polar capsules are equal, pear-shaped measuring 4.8-5.2(5.0±0.28)×1.5-2.3(1.9±0.56)μm in size, each with a neck leading to a fine duct opening independently. Both polar capsules converge slightly anteriorly but diverge apart posteriorly occupying more than half of spore body. Intercapsular appendix is absent. Earlier, the parasite was recorded in the buccal cavity, muscles and lips of Plectorhynchus gaterinus (Forsskal), Egypt. A new locality-Ropar Wetland, a new location-scales and a new host- Labeo rohita (Hamilton) are recorded for this parasite.

Molecular and Morphological Analysis of Myxobolus Spp. of Salmonid Fishes with the Description of a New Myxobolus Species

While investigating the parasite fauna of wild coho salmon. Oncorhynchus kisutch (Walbaum, 1792), histological examination provided evidence of a new species of Myxobolus (Myxozoa: Myxosporea) infecting nerves of skeletal muscle. Spores were morphologically similar to those of the intramuscular Myxobolus insidiosus Wyatt and Pratt, 1963, both having pyriform spores with clavate polar capsules. However, the former developed exclusively in the nerves of skeletal muscle rather than in myocytes. We examined both species of Myxobolus derived from coho salmon; Chinook salmon, Oncorhynchus tshawytscha (Walbaum, 1792); cutthroat trout, Oncorhynchus clarkii (Richardson, 1836); and rainbow trout Oncorhynchus mykiss (Walbaum, 1792) from freshwater in Oregon. Spore morphology, small subunit ribosomal RNA gene (rDNA) sequences, and site of infection were compared. Myxobolus arcticus Pugachev and Khokhlov, 1979 has pyriform spores, infects the central nervous system of many salmonids, and is found in the Pacific Northwest. It was therefore included in the analyses to rule out conspecificity with the new species. Together, these data show that the Myxobolus sp. from peripheral nerves in the skeletal musculature of coho salmon, rainbow trout, and cutthroat trout is a new species, described herein as Myxobolus fryeri n. sp.