Myxobolus Species Research Articles

Description of new types of sphaeractinomyxon actinospores (Myxozoa: Myxosporea) from marine tubificid oligochaetes, with a discussion on the validity of the tetraspora and the endocapsa as actinospore collective group names.

Ten new types of sphaeractinomyxon actinospores are morphologically and molecularly described from the coelomic cavity of two marine oligochaete hosts, Limnodriloides agnes (Hrabě, 1967) and Tubificoides pseudogaster (Dahl, 1960), from Aveiro estuary, Portugal. The smallest sphaeractinomyxon type measured 17μm (length) × 19μm (width) × 19μm (apical diameter), whereas the largest type measured 61μm × 76μm × 80μm. While considering the 10 types of sphaeractinomyxon, it was found that the number of spores developing inside pansporocysts varied between 1, 2, 4, and 8. The total prevalence of infection was of 19% for the two host species, with a maximum recorded for spring and summer (25-26%). While considering each type of sphaeractinomyxon individually, it was found that the prevalence values ranged between 0.3 and 1.7%. All described sphaeractinomyxons were most similar to Myxobolus species. The validity of the tetraspora and endocapsa collective group names is discussed.

Supplemental description and molecular characterization of Myxobolus miyarii Kudo, 1919 (Myxosporea: Myxobolidae) infecting intestine of Amur catfish (Silurus asotus).

Myxobolus miyairii Kudo, 1919 was first reported from the intestines of the Amur catfish (Silurus asotus) in Japan and then in China and Russia, but with incomplete description. During the investigation of fish myxosporean diversity in Poyang Lake, the biggest lake along the Yangtze River, China, two Amur catfish highly infected with M. miyairii in the intestine wall were sampled. So, the complete description of this species with morphological and molecular data was presented here. A large number of whitish, round or ellipsoidal pseudocysts 0.32-0.78 mm in diameter could be found in the external intestinal wall after dissecting the infected fish. Mature spores of M. miyairii were elongated and ellipsoidal in the frontal view and narrow fusiform in the lateral view, with a slightly pointed anterior end and a bluntly rounded posterior end and measured 13.3 ± 0.49 (12.5-14.7) μm × 6.6 ± 0.27 (6.2-7.4) μm × 5.0 ± 0.26 (4.4-5.7) μm in size. Spore surface was smooth and two spore valves symmetrical, with a thin and straight sutural ridge. Interestingly, two types of caudal appendage (single or bifurcated) were occasionally present on the posterior end of some spores which has not previously been reported. The two equal pyriform polar capsules measured 6.5 ± 0.30 (6.2-7.5) μm long and 1.9 ± 0.14 (1.5-2.3) μm wide and situated at the anterior end of the spore. Polar filaments coiled with eight to nine turns, perpendicularly to the longitudinal axis of the polar capsules. Histopathological analysis showed that the plasmodium developed in the circular muscle layer of intestinal wall of Amur catfish, but no obvious inflammatory responses were observed. Phylogenetic analysis based on the partial 18S small subunit ribosomal DNA sequences indicates that M. miyairii cluster within a clade of Siluriforme-infecting Henneguya species with the support of a high bootstrap value, but also evolutionarily independent from the Henneguya clade infecting the epithelium of fish of the Ictaluridae family. Additionally, Myxobolus species reported with caudal processes dispersed within the Henneguya-Myxobolus clade.

Morphological and molecular characterization of Myxobolus mucosus sp. n. (Myxosporea: Myxobolidae) with basifilamental sporulation in two cyprinid fishes, Rutilus rutilus (L.) and Leuciscus leuciscus (L.) in Russia.

A new Myxobolus species, Myxobolus mucosus sp. n., was found in the basifilamental location of roach, Rutilus rutilus, and common dace, Leuciscus leuciscus, during the investigation of fish myxosporean fauna in Finnish Bay of Baltic Sea and Lake Ladoga in 2014. Plasmodia from the two hosts share similar morphometric and morphological features which are whitish and slightly elongated oval and measured 300-500 μm in diameter. Mature spores of M. mucosus sp. n. are ellipsoidal in frontal view and lemon shaped in sutural view, measuring 13.6 ± 0.62 (12.8-14.2) μm in length, 10.7 ± 0.51 (10.3-11.4) μm in width, 7.8 ± 0.41 (7.2-8.3) μm in thickness and 13.0 ± 0.89 (11.5-14.2) μm in length, 10.8 ± 0.77 (10.2-11.5) μm in width, 7.7 ± 0.52 (7.3-8.0) μm in thickness from roach and common dace, respectively. Polar capsules were pyriform, equal in size, converging anteriorly, with 5.9 ± 0.22 (5.7-6.3) μm in length and 3.9 ± 0.3 (3.5-4.1) μm in width and 5.6 ± 0.38 (5.1-6.2) μm in length and 3.8 ± 0.24 (3.5-4.0) μm in width from roach and common dace, respectively. Spore valves are relatively thin, symmetrical, and smooth. The most remarkable morphological character of this new Myxobolus species is the distinct mucous envelope, surrounding the full myxospore valves, up to 25 and 32 μm, respectively, in roach and common dace. The partial 18S ribosomal DNA (rDNA) sequence variation of myxospores from two hosts is very tiny (below 0.8 %) but significantly differing from all available sequences of myxosporeans in GenBank. Therefore, it can be concluded that this myxosporean from these two closely related cyprinids are conspecific by combining morphological characteristics, tissue specificity, and molecular data. Phylogenetic analysis showed that this newly described species cluster with several gill-infecting Myxobolus species from cyprinid fish inhabiting in Eastern Europe.

Description of a myxozoan parasite Myxobolus sp.n PKB2014 from an edible fish, with emphasis on its molecular characterization.

In India, more than 104 species of Myxobolus have so far been reported infecting freshwater as well as marine fishes. The study focuses on the description of a new myxosporean species, Myxobolus sp.n PKB 2014 from the gill lamellae of an Indian major carp Labeo rohita. The species have been described on the basis of morphological characterization of the spores, tissue architecture and 18S rDNA sequence data. The plasmodia of Myxobolus sp.n PKB 2014 were round in shape measuring, 50 to 70 μm in diameter and spores were ellipsoidal in frontal view measures 14.7 ± 0.51 μm. The 18S rRNA nucleotide sequence with 806 bp of Myxobolus sp.n PKB 2014 (Accession number KJ652226) clustered phylogenitically with other Myxobolus spp. infecting cyprinid gills with 90-99% similarity. According to the phylogenetic study we concluded that M. wulli was the closest relative having 99% similarity with the species under description but the sequence was distinct in each species which additionally exhibited different morphological features. The infection rate was low to moderate. After through comparison it can be concluded that the species being described here is new to science which is designated as Myxobolus sp.n. PKB 2014.

Molecular identification of a new myxozoan, Myxobolus dermiscalis n. sp. (Myxosporea) infecting scales of Labeo rohita Hamilton in Harike Wetland, Punjab (India).

In the present study, a new species Myxobolus dermiscalis n. sp. infecting scales of Labeo rohita, an Indian major carp from Harike Wetland in Punjab, India has been described on the basis of spore morphology and amplification of a part of 18S rDNA gene. The pseudocysts of M. dermiscalis n. sp. are milky white with irregular outline, 0.5–3.6 mm in diameter embedded within the dermal scale in the form of a cavity. The spores 5.84–7.98 × 3.98–5.98 μm in size, having two equal polar capsules 3.98–5.98 × 1.85–3.85 μm in size. The most differentiating feature from closely related species, Myxobolus saugati (Kaur and Singh, 2011) is the presence of two parietal folds at the posterior – lateral margins of the shell valves. The present species is regarded as host, organ and tissue specific in nature. The partial sequence of SSU gene of M. dermiscalis n. sp. clustered with other Myxobolus species infecting cyprinids available in the GenBank. Blast search revealed 98% homogeneity with Myxobolus sp (KM401439) infecting scales of L. rohita in Myanmar (unpubl. data). The present myxobolid parasite has been recorded to cause serious, highly symptomatic disease of the scales, causing their loosening from the skin of L. rohita. It rendered the host fish unsightly giving it cloudy appearance with white patches and mucoid body surface. Scale pseudocyst Index (SPI) has been provided to record the intensity of infection.

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.

Specific PCR for Myxobolus arcticus SSU rDNA in juvenile sockeye salmon Oncorhynchus nerka from British Columbia, Canada.

A PCR for the specific detection of the salmon brain parasite Myxobolus arcticus (Pugachev and Khokhlov, 1979) was developed using primers designed to amplify a 1363 base pair fragment of the small subunit rDNA. The assay did not amplify DNA from 5 other Myxobolus species or from 7 other myxozoan species belonging to 5 other genera. For juvenile sockeye salmon Oncorhynchus nerka (Walbaum) collected from Chilko Lake, British Columbia (BC), Canada, in 2011, the prevalence by PCR was 96%, in contrast to 71% by histological examination of brain tissue. In 2010, the histological prevalence was 52.5%. Sequence identity between M. arcticus from Chilko Lake and other sites in BC ranged from 99.7 to 99.8% and was 99.6% for a Japanese sequence. In contrast, an M. arcticus sequence from Norway shared 95.3% identity with the Chilko Lake sequence, suggesting misidentification of the parasite. Chilko Lake sockeye salmon were previously reported free of infection with M. arcticus, and more research is required to understand the processes involved in the local and global dispersion of this parasite.

Supplementary studies and the first molecular data on Myxobolus scardinii Reuss, 1906 (Myxozoa: Myxosporea) infecting the gill filaments of rudd, Scardinius erythrophthalmus (L.).

Within the present study, we offer new information on the morphology, histopathology, and 18S ribosomal DNA (rDNA) sequence of Myxobolus scardinii to supplement and revise the original description of Reuss (Bull Acad Imp Sci St-Pétersbourg, V Serie, XXV, No. 3: 199-205, 1906). M. scardinii was found infecting the gills of 6 of 125 specimens (4.8%) of Scardinius erythrophthalmus from northern Turkey. Large mature plasmodia, whitish, spherical, or ellipsoidal, measuring 0.9-1.0 mm in diameter, macroscopically occurred in the gills. Histopathological examination indicated that development of the cyst-like plasmodia was intrafilamental-vascular type. Mature spores are oval or shortly ellipsoidal. The spores are 12.1 ± 0.2 (11.5-12.6) μm long, 8.9 ± 0.3 (8.4-9.2) μm wide, and 6.1 ± 0.3 (5.9-6.2) μm thick. The two polar capsules are equal in size, 4.8 ± 0.2 (4.7-5.1) μm long and 2.8 ± 0.2 (2.7-3.1) μm wide, and are long pyriform in shape. A well-developed intercapsular appendix was found in the fresh spores. In this study, a specific gill myxosporean of S. erythrophthalmus, M. scardinii the identity of which was confirmed by careful morphological and histopathological examination, was sequenced with its 18S rDNA sequence for the first time and submitted to Genbank database (accession number KJ562362). Phylogenetic analysis of the 18S rDNA gene revealed that M. scardinii had the closest similarity to M. muelleri and M. bramae. This is the first molecular data for the validity of M. scardinii in S. erythrophthalmus. This new valid genetic data (KJ562362) has been used to establish phylogenetic relationships with other similar gills Myxobolus species from Eurasia.

Morphology, ultrastructure and phylogeny of Myxobolus curimatae n. sp. (Myxozoa: Myxosporea) a parasite of Prochilodus costatus (Teleostei: Prochilodontidae) from the São Francisco River, Brazil

Myxobolus curimatae n. sp. has been found infecting the gill filaments of Prochilodus costatus (Prochilodontidae) from the São Francisco River in the state of Minas Gerais, Brazil. The prevalence of the species was 18.7%. Mature spores were rounded from a frontal view, with elongated polar capsules of equal size, and had polar filaments with 9–10 turns. Ultrastructural analysis revealed that sporogenesis patterns followed those of other Myxobolus species. The plasmodium walls had numerous invaginations and protrusions, and few pinocytic channels. Numerous mitochondria, generative cells and young pansporoblasts were observed in the peripherical areas of the plasmodia, and mature spores were found in deeper layers. A layer of collagenic fibrils surrounded the plasmodia. The morphological data and molecular analysis of the 18S rDNA identified this parasite as a new species. The maximum likelihood phylogenetic tree showed M. curimatae n. sp., as a sister species of Thelohanellus marginatus, in a basal branch of the subclade composed by parasites with tropism to different organs and host families.

Twelve myxosporean species of the family Myxobolidae infecting freshwater fishes of the River Nile, Egypt, with the description of four novel species.

Myxosporidian parasites infecting fish are very dangerous parasites causing severe damage to a large number of economically important fishes especially in aquaculture. A survey of myxosporean parasites infecting four species of fishes from the River Nile in Egypt is conducted. One hundred and ninety-five out of 316 fish specimens with a percentage of 61.7% were found to be naturally infected with these parasites. Light microscopic examination of different tissues revealed the presence of 12 myxosporean species belonging to the family Myxobolidae. Four of the identified species are novel and the other eight species are redescribed. Myxidium sp.nov. a coelozoic species inhabiting the gallbladder of Labeo niloticus with its mature spores float free in bile was detected. These spores possess a fusiform, straight, or slightly crescentic shape with less pointed ends and two equal polar capsules. Three novel histozoic Myxobolus species infecting Oreochromis niloticus were identified. Myxobolus sp(1).nov. is a species inhabiting kidney tissue with ovoid spores exhibiting a small intercapsular appendix. Myxobolus sp(2).nov. and Myxobolus sp(3).nov. recovered from kidney and intestinal tissues. Spores of Myxobolus sp(2).nov. are elliptical in shape with an anterior end wider than posterior one. Their two polar capsules are ovoid to pyriform occupied nearly the first third of the spore body. Spores of Myxobolus sp(3).nov. are broader than long with nearly rounded or ovoid two polar capsules. Eight species of the recovered myxosporean parasites are redescribed, Myxobolus niloticus Fahmy et al., 1971 from pectoral, dorsal, and tail fins of L. niloticus, Henneguya suprabranchiae Landsberg, 1987, and Henneguya branchialis Ashmawy et al., 1989 are recovered from the gills and suprabranchial organ of the catfish Clarias gariepinus, respectively, Myxobolus naffari Abdel-Ghaffar et al., 1998 and Myxobolus imami Ali et al., 2002 are found in the kidney of Barbus bynni and L. niloticus, Myxobolus caudatus Ali et al. & Parasitol Res (2002) from Tail fin of B. bynni, Myxobolus fomenai Abdel-Ghaffar et al., 2008 from kidney and intestinal tissues of O. niloticus, Thelohanellus niloticus Abdel-Ghaffar et al., 2012 are observed in the gills of L. niloticus.

Description of Myxobolus balatonicus n. sp. (Myxozoa: Myxobolidae) from the common carp Cyprinus carpio L. in Lake Balaton

Myxobolus balatonicus n. sp. was detected in the gill filaments of the common carp Cyprinus carpio L. collected in Lake Balaton, Hungary. Its oval plasmodia measuring 600-800×300-400 µm were located intravasally in the filamental arteries. The spores measured 11.2 ± 0.92×9.5±0.41×7.4±0.33 µm and had two equal polar capsules with six filamental turns. Both morphology and DNA sequence analysis revealed that M. balatonicus n. sp. is distinct from the ten species of Myxobolus Bütschli, 1882 described from the European common carp and the 21 species described from the Asian common carp subspecies. Phylogenetic analysis placed M. balatonicus n. sp. in a clade of gill-infecting myxobolids.

First report of Myxobolus sp. infection in the skeletal muscle of Neotropical freshwater fish Piaractus mesopotamicus.

Although there are several reports of Myxobolus species infecting the somatic muscle of teleost fish, species of this genus have not been described parasitizing the muscle tissue of pacus, Piaractus mesopotamicus. This study presented the first report of natural infection by Myxobolus sp. in the skeletal muscle of pacus reared in intensive system. Twenty-one fish (±142.2 g; ±23.1 cm) were captured (April 2013) from an intensive fish farm in São Paulo State, southeast Brazil. Spores of Myxobolus sp. were contained within plasmodia and showed oval morphology with the apical portion slightly pyriform and two polar capsules pyriform retaining the same ratio to each other. In the histopathological study, the skeletal muscle do not present signs of inflammation. The integrity of myofibrils within the infected fibers showed some degree of degeneration, with partial loss of myofibrillar details and striations. Spores were found infecting the skeletal muscle of 18 fish (85.7%). Finally, the high prevalence of Myxobolus sp. infection in the skeletal muscle of P. mesopotamicus and the absence of macroscopic lesions in the muscle tissue indicate the necessity of more meticulous examinations during the health management in the rearing system and at slaughter of pacus to ensure best quality of meat.

Enteric pathogens of food sellers in rural Gambia with incidental finding of Myxobolus species (Protozoa: Myxozoa)

Ongoing surveillance of enteric pathogens of public health significance among casual food sellers is undertaken in many resource-limited countries. We report the results of a survey in Kiang West province, The Gambia, and provide an exemplar methodology for such surveys in resource-limited laboratories. Unpreserved, unrefrigerated stool samples were subjected to Salmonella, Shigella and agar plate culture for rhabditoid nematodes. Direct microscopy, formalin-ethyl acetate concentration and iron-hematoxylin staining was performed later, following preservation. Of 128 specimens received, no Shigella spp. was recovered, while four serovars of non-typhoidal Salmonella enterica, including Chandans, were isolated. Pathogenic parasitic infections were Necator americanus 10/128 (7.8%), Strongyloides stercoralis 3/128 (2.8%), Blastocystis species 45/128 (35.1%), Entamoeba histolytica complex 19/128 (14.8%) and Giardia intestinalis 4/128 (3.1%). A single case each of Hymenolepis diminuta and S. mansoni infection were detected. In one participant, myxozoan spores identical to those of Myxobolus species were found. Rare parasitoses and serovars of Salmonella enterica may occur relatively commonly in rural Africa. This paper describes intestinal pathogens found in a cohort of food sellers in such a setting. Furthermore, it describes two parasites rarely recovered from humans and demonstrates the need for methods other than microscopy to detect S. stercoralis infections.

A new record of Myxobolus brachysporus and M. israelensis in the tilapia (Oreochromis niloticus) collected from the Nile River, Egypt

The present study was carried out as part of an ongoing general survey for myxosporean parasites infecting tilapias in the River Nile, Egypt. In the present study, 77 Nile tilapia (Oreochromis niloticus) were collected from boat landing sites at Beni-Suef governorate, Egypt and examined for the myxosporean infection. The infection was encountered as a huge number of free spores in the kidney and the spleen. The infection showed a prevalence of 51.9% (40/77) for Myxobolus brachysporus while it was 25.9% (20/77) for Myxobolus israelensis. Mature spores of M. brachysporus were ellipsoidal and measured 8.6×13.2μm. The polar capsules were subcircular with 5–6 filament turns and measured 4.7×3.6μm. Spores of M. israelensis were ellipsoidal in the frontal view and fusiform in the lateral view. Spore measurements were 13.4μm long and 8.7μm wide. The polar capsules were elongated with 6–7 filament coils and measured 8.6×3.1μm. The findings presented here proved that tilapia fishes in the Nile River are still suffering from infections with Myxobolus species. Therefore, further studies should be carried out to survey the Myxobolus infection among tilapias under culture conditions to clarify the pathological impacts of this parasite in tilapias aquaculture.

Two Myxobolus spp. infecting the kidney of Nile tilapia (Oreochromis niloticus) in the River Nile at Beni-Suef governorate, Egypt, and the associated renal changes.

Two Myxobolus spp. are described from the kidney of the Nile tilapia (Oreochromis niloticus) collected from the River Nile, Egypt. The prevalence of infection was 61 % (47/77), with the infected fish in each case parasitized by the two Myxobolus species simultaneously. The infection was exhibited as free spores in Bowman capsules and renal glomeruli, which makes their original structures difficult to discern. In some cases, the infection appeared as a fibrous plasmodia-like structure containing degenerated developmental stages and spores in the interstitium. The paper identifies each species based on the morphological characteristics of its spores and identifies the histological impacts of Myxobolus infection in this species of fish.

Myxobolus oralis sp. n. (Myxosporea: Bivalvulida) infecting the palate in the mouth of gibel carp Carassius auratus gibelio (Cypriniformes: Cyprinidae)

During a survey on the myxosporean fauna of gibel carp Carassius auratus gibelio (Bloch) in China, a species of Myxobolus Bütschli, 1882 that did not conform to any known species was found. The species is characterised by the presence of round to ellipsoidal plasmodia of 2.6-4.0 mm in diameter in the palate of host. Mature spores are obovate in frontal view and lemon-shaped in lateral view, with the following range, mean and standard deviation of dimensions: 10.8-12.8 μm (11.7 ± 0.4 μm) long, 8.2-9.9 μm (8.9 ± 0.4 μm) wide and 6.0-7.5 μm (6.8 ± 0.3 μm) thick. Two polar capsules are pyriform, 4.0-5.5 μm (4.8 ± 0.3 μm) long by 2.9-3.6 μm (3.0 ± 0.2 μm) wide. Polar filaments are coiled, with 5 to 6 turns. A small proportion of spores possesses a short caudal process. Scanning electron microscopy revealed discoid spores with a low sutural ridge and middle bulge. The small subunit ribosomal DNA sequence of this species did not match any available sequences in GenBank. Phylogenetically, this species is sister to M. nielii (Nie et Li, 1973) and M. hearti Chen, 1998 in a Henneguya-Myxobolus clade with robust support. Given the morphological and molecular differences between this species and other Myxobolus species, we propose the name Myxobolus oralis sp. n. for this parasite from gibel carp.

Infection of the heart of Pimelodus ornatus (Teleostei, Pimelodidae), by Myxobolus sp. (Myxozoa, Myxobolidae).

The phylum Myxozoa Grassé, 1970, consists of a heterogenous group of around 50 genera that are worldwide disseminated in a wide variety of aquatic media. In the present study, 43 specimens of Pimelodus ornatus were collected from an adjacent area to the Cachoeira do Arari municipality on Marajó Island, in the Brazilian state of Pará, in 2013. Macroscopic analysis showed the presence of whitened plasmodia located in the cardiac muscle and also in the region between the bulbus arteriosus and atrium cordis. Microscopic analysis on the parasitized tissues revealed spores that were typically piriform, with the anterior portion slightly narrower than the posterior end. The spore valves were symmetrical. The present species is placed in the genus Myxobolus Butschli, 1882, because of the presence of a pair of equal polar capsules in each spore. The prevalence of parasitism observed was 13.9% (6/43). This research note reports the first occurrence of Myxobolus as a parasite of the heart in the teleostean fish P. ornatus in the Amazon region and confirms the occurrence of secondary myocarditis in this fish, caused by parasitism by Myxobolus sp. The rarity of this parasitic species of Myxobolus at this tissue site, associated with other spore morphology characteristics in the fish, suggests that it is an undescribed species.

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.

Prevalence, morphology and scanning electron microscopy study of myxozoan parasites.

The present study was conducted from Garia, West Bengal, India to study the Prevalence, Morphology, Severity of infestation and Scanning Electron Microscopy of Myxozoan parasites in Indian Major Carps. A total of 155 fishes were examined, out of which 80 were found infected with myxozoan parasites (51.61%) and severity of infestation varied from 0.5 to 2. Three known species Myxobolus orissae, M. carnaticus and Thelohanellus caudatus were found infecting various organs such as gills and fins of Indian major carps. Spores of the species, T. caudatus measures 12.84±0.77 (11.4-14.2)μm×8.5±0.71 (7.6-9.6)μm and was elongated pyriform in shape with rounded posterior and tappering anterior end. Parietal folds were absent. The single polar capsule is rounded to oval shaped with slightly pointed anterior end and broad posterior end with size measuring 6.15±2.09 (4.2-10.4)μm×3.85±1.18 (2.3-4.9)μm. M. orissae, size of the mature spore measures 15.6-19.7 (17.25)μm×5.7-9.3 (6.70)μm and was elongated pyriform in shape. Two polar capsules are distinctly unequal. Large one measures 6.8-13.5 (8.75)×1.4-3.1 (1.90)μm and smaller one 6.9-11.5 (7.44)×1.7-2.4 (1.57)μm in size. Both are broadly pyriform with pointed pointed anterior end and rounded posterior end. Myxobolus carnaticus mature histozoic spores measures 8.1-12.9 (9.49)×7.2-10 (8.27)µm are creamy white to yellow in colour tear shaped in valvular view with rounded posterior and bluntly pointed anterior ends.

Myxobolus anatolicus sp. nov. (Myxozoa) infecting the gill of Anatolian khramulya Capoeta tinca (Cyprinidae) in Turkey.

This work is part of an ongoing investigation into the characteristics of myxozoan parasites of freshwater fish in Turkey and was carried out using morphology, histopathology and molecular analysis. A new species of the genus Myxobolus (M. anatolicus sp. nov.) was found infecting the gills of 3 of 34 specimens (8.8%) of Anatolian khramulya Capoeta tinca from the Samsun Province, Northern Turkey. Both morphology and 18S rDNA sequence data revealed that M. anatolicus sp. nov. was distinct from other Myxobolus species found in the gills of cyprinid fishes. The small, white and round-shaped plasmodia, measuring 0.2 to 1.4 mm in diameter, were observed macroscopically in the gills. Histological analysis revealed that the cyst-like plasmodia have an intralamellar-vascular type development. Mature spores of M. anatolicus sp. nov. were oval in both frontal and sutural views, and tapered at the anterior poles. The spores were 10.1 ± 0.41 (9.4 to 10.7) µm long, 6.9 ± 0.28 (6.6 to 7.2) µm wide, and 4.5 ± 0.36 (4.4 to 4.6) µm thick. The 2 polar capsules were pyriform, equal in size, 4.6 ± 0.45 (4.4 to 4.8) µm long and 2.1 ± 0.12 (2 to 2.3) µm wide. Polar filaments within the polar capsules were coiled with 5 or 6 turns. Phylogenetic analysis placed M. anatolicus sp. nov. in a clade of gill-infecting myxobolids. This is the first record of a Myxobolus species infecting Anatolian khramulya Capoeta tinca, and the first record of this species from Eurasia.