Novel Myxobolus and Ellipsomyxa species (Cnidaria: Myxozoa) parasiting Brachyplatystoma rousseauxii (Siluriformes: Pimelodidae) in the Amazon basin,Brazil

We describe two novel myxosporean parasites from Brachyplatystoma rousseauxii, an economically important freshwater catfish from the Amazon basin, Brazil. Myxobolus tapajosi n. sp., was found in the gill filaments of 23.5% of 17 fish, with myxospores round to oval in frontal view and biconvex in lateral view: length 15 (13.5–17) μm and width 10.7 (9.6–11.4) μm; polar capsules equal, length 5.8 (4.6–7.1) μm and width 3 (2.3–3.8) μm containing polar tubules with 6–7 turns. Ellipsomyxa amazonensis n. sp. myxospores were found floating freely or inside plasmodia in the gall bladder of 23.5% of fish. The myxospores were ellipsoidal with rounded extremities: length 12.8 (12.3–13.6) μm and width 7.6 (6.7–8.7) μm; with two equal, slightly pyriform polar capsules, length 3.8 (3.8–4.0) μm and width 3.1 (2.5–3.4) μm, containing polar tubules with 2–3 turns. We combined spore morphometry, small-subunit ribosomal DNA data, specific host, and phylogenetic analyses, to identify both of these parasites as new myxozoan species. Maximum likelihood and Bayesian analyses showed that Myxobolus tapajosi n. sp. clustered in a basal branch in a subclade of parasites from exclusively South American pimelodid fishes. Ellipsomyxa amazonensis n. sp. clustered within the marine Ellipsomyxa lineage, but we suspect that although the parasite was collected in freshwater, its hosts perform a large migration throughout the Amazon basin and may have become infected from a brackish/marine polychaete host during the estuary phase of its life.     

倒刺鲃两极虫的宿主新记录及其分子系统学研究

为弄清倒刺鲃两极虫(Myxidium spinibarba)的宿主多样性和胭脂鱼(Myxocyprinus asiaticus)寄生黏孢子虫的种类组成,研究基于形态和分子数据,比较分析了寄生于不同宿主的倒刺鲃两极虫的形态学和形态计量学特征及分子系统发育关系。结果显示:寄生于胭脂鱼和中华倒刺鲃的倒刺鲃两极虫株系在形态学和形态计量学上未出现显著性差异, 18S rDNA序列相似度为99.9%—100.0%,遗传距离为0.000—0.001,符合种内变异;寄生于不同宿主倒刺鲃两极虫的株系在系统发育树中嵌合聚支,且寄生于胭脂鱼的倒刺鲃两极虫株系先分化。以上结果表明:研究中两株系与倒刺鲃两极虫为同一物种,但在分子水平已经出现分化;这是首次在胭脂鱼中检获到黏孢子虫,胭脂鱼是倒刺鲃两极虫的新宿主。     

Morphologic and Genetic Evidence for Mixed Infection with Two Myxobolus Species (Myxozoa: Myxobolidae) in Gray Mullets,Mugil cephalus,from Korean Waters

The present study was performed to trace the decisive evidence for mixed infection of 2 Myxobolus species, M. episquamalis and Myxobolus sp., in the gray mullet, Mugil cephalus, from Korean waters. Mullets with whitish cyst-like plasmodia on their scales were collected near a sewage plant in Yeosu, southern part of Korea, in 2009. The cysts were mainly located on scales and also found in the intestine. The spores from scales were oval in a frontal view, tapering anteriorly to a blunt apex, and measured 7.2 µm (5.8-8.0) in length and 5.3 µm (4.7-6.1) in width. Two polar capsules were pyriform and extended over the anterior half of the spore, measuring 3.5 µm (2.3-4.8) in length and 2.0 µm (1.5-2.2) in width. In contrast, the spores from the intestine were ellipsoidal, 10.4 µm (9.0-11.9) in length and 8.4 µm (7.3-10.1) in width. The polar capsules were pyriform but did not extend over the anterior half of the spore, 3.7 µm (2.5-4.5) in length and 2.2 µm (1.8-2.9) in width. The nucleotide sequences of the 18S rDNA gene of the 2 myxosporean spores from scales and intestine showed 88.1% identity to each other and 100% identity with M. episquamalis and 94.5% identity with M. spinacurvatura from mullet, respectively. By the above findings, it is first confirmed that mullets from the Korean water are infected with 2 myxosporean species, M. episquamalis and Myxobolus sp.     

Ortholinea scatophagi (Myxosporea: Ortholineidae), a novel myxosporean infecting the spotted scat,Scatophagus argus (Linnaeus 1766) from southwest coast of India

A new species of myxosporean, Ortholinea scatophagi n. sp. infecting the urinary bladder of the spotted scat, Scatophagus argus (Linnaeus 1766) is described. O. scatophagi n. sp. is characterized by spherical myxospores with a slightly flattened anterior end and equal spore valves with extra sutural ridges on its surface; measured 7.34 ± 0.67 μm in length, 6.90 ± 0.71 μm in width and 6.48 ± 0.37 μm in thickness. Two polar capsules, equal, spherical to oval in shape, arranged diametrically opposite and measured 2.59 ± 0.42 μm in length and 2.24 ± 0.35 μm in width. Polar filaments, 21.84 ± 2.86 μm long, with four to five coils. Scanning electron microscopy revealed the presence of extra sutural ridges on spore surface. Pansporoblasts spherical to irregular in shape, measured 31.08 ± 2.67 μm in length and 13.88 ± 5.40 μm in width; Monosporic, disporic and polysporic plasmodial stages were observed; plasmodia spherical or irregular in shape with granular cytoplasm containing refractile granules. The species was compared with 23 existing nominal species of Ortholinea, based on morphology and morphometry. Molecular analysis resulted in a 1773 bp long SSU rDNA sequence (GenBank accession number MN 310514). In phylogenetic analyses the present parasite clustered with other members of Ortholinea, under the freshwater urinary clade. Considering the morphologic, morphometric and molecular differences with previously described species of Ortholinea, and differences in host and geographic locations, the present species is treated as new and the name Ortholinea scatophagi n. sp.is proposed.     

Novel and known myxobolids (Cnidaria,Myxozoa) infecting Chondrostoma angorense (Cypriniformes: Leuciscidae) in Turkey

Turkey has more than 200 endemic freshwater fish species, one of which is the Ankara nase, Chondrostoma angorense Elvira, 1987 (Cypriniformes: Leuciscidae), a food fish in northern Turkey. Like most endemic fish species in Turkey, its myxosporean parasite fauna (Cnidaria: Myxosporea) are not yet described. We surveyed twenty C. angorense from Lâdik Lake in northern Turkey, and identified two myxosporean parasites from gills of these fish: Myxobolus arrabonensis Cech, Borzák, Molnár, Székely, 2015, and a co-infection of a novel species, Myxobolus polati sp. nov. We characterized both infections based on myxospore morphology, morphometry, tissue tropism, small subunit ribosomal DNA sequence and phylogenetic analysis. Plasmodia of both species were observed in gills, but had distinct tropism: M. arrabonensis is an intrafilamental vascular type, and M. polati sp. nov. is an intralamellar vascular type. We identified M. arrabonensis on the basis of myxospore characters and 100% similarity to the type DNA sequence from the closely-related host C. nasus. The small subunit ribosomal DNA sequence of M. polati sp. nov. (1946 base pairs; GenBank Accession number MH392318) had a maximum similarity of 98% with any Myxobolus sp. from other Eurasian cypriniforms. Phylogenetic analysis revealed that M. polati sp. nov. is most closely related to gill-infecting Myxobolus diversicapsularis from Rutilus rutilus (L.). The present study is the first record of myxosporean species infecting C. angorense comprising a novel species, M. polati sp. nov. and a known species M. arrabonensis.     

An ultrastructural and histopathological study of Henneguya pellucida n. sp. (Myxosporea: Myxobolidae) infecting Piaractus mesopotamicus (Characidae) cultivated in Brazil

During a study of myxosporean parasites of cultivated freshwater fish, a new myxosporean species, Henneguya pellucida n. sp., was discovered. Of the 120 Piaractus mesopotamicus sampled, only 10 specimens (8.3%) were infected. Yellow, round plasmodia measuring 0.5-3 mm were found in the serous membrane of the visceral cavity and in the tunica externa of the swim bladder. Sporogenesis was asynchronous, with the earliest developmental stages aligned prevailingly along the endoplasmic periphery and mature spores in the central zone. The mature spores were pear shaped (total length: 33.3 +/- 1.5 microm, mean +/- SD; width: 4.1 +/- 0.4 microm; body length: 11.4 +/- 0.3 microm; caudal process length: 24.1 +/- 1.5 microm). The polar capsules were elongated (length: 4.0 +/- 0.4 microm; width: 1.6 +/- 0.2 microm). The development of the parasite in the swim bladder produced thickening of the tunica externa and a granulomatous reaction. There was no correlation between the prevalence of the parasite and the chemical and physical characteristics of the water. Infection was recorded only in juvenile specimens ranging in size from 9.5 to 20 cm.     

New species of myxosporidia (Myxozoa: Myxosporea) of fish from the northwestern Sea of Japan

Three new species of mixosporidia of the genera, Myxidium and Myxoproteus, from the gall bladder and urinary bladder of fishes from Japan Sea: Myxidium licodae sp. n., M. rarum sp. n., and Myxoproteus ovale sp. n.     

The influence of Myxidium gadi Georgievitsch, 1916 (Myxozoa: Myxosporea) on the level of lipid reserves in the tissues of the Black Sea whiting Merlangius merlangus euxinus at different periods of the annual cycle

Concentration of total lipids and main lipid classes in the tissues of the Black Sea whiting males and females under different degrees of their infestation with the myxosporean Myxidium gadi is studied. Fishes were examined during the periods of fattening and spawning. Decrease of the total lipid (2-3 times) and triacylglycerol (3-4 times) concentration in the liver of heavily ingested males is revealed, as compared with the weakly infested fishes. However this effect has not been found in the fish females.     

A New Myxosporean Parasite, Kudoa Camarguensis N. Sp., Recorded On Two Goby Species (Teleostei: Pisces) In the Rhône Delta (Mediterranean Sea, France)

ABSTRACT. A new species of myxosporean of the genus Kudoa was found in the muscle tissues of Pamatoschistus minutus (Pallas, 1770), a migratory fish species from the Mediterranean Sea. Previously this Kudoa species had been observed in Pomatoschistus microps (Krøyer, 1838), a sedentary species of the Vaccarés lagoon system. the parasite caused rapid myoliquefaction of the affected muscles within one hour after host death. Using both light and electron microscopy, whitish, longitudinal, spindle-shaped bodies, 2-5 mm long and 1-2 mm wide, were found in the caudal peduncle or in muscle tissues of the abdominal wall. Spore length, width, and thickness (n = 30) ranged between 4.4-6.0 üm, 6.4-8.0 üm, and 4.4-6.0 üm, respectively, while the polar capsules averaged 2.5 times 1.5 üm (n = 30). Anatomic comparison with other myxosporean parasites enabled us to determine this to be a new species that we name Kudoa camarguensis n. sp.     

Ultrastructural aspects and molecular phylogeny of <Emphasis Type="Italic">Auerbachia maamouni</Emphasis> n. sp. (Myxosporea: Bivalvulida) from the gallbladder of <Emphasis Type="Italic">Gnathanodon speciosus</Emphasis> Forsskål (Actinopterygii: Carangidae) in the Red Sea

A new myxosporean parasite, Auerbachia maamouni n. sp., infecting the gallbladder of the golden trevally Gnathanodon speciosus Forsskål, is described, based on morphology, ultrastructure, and small subunit (SSU) rRNA gene sequencing. Of 50 fish collected from the Red Sea in Jeddah, Saudi Arabia, five were found heavily infected with mature myxospores floating free in the bile. Mature spores are pyriform to club-shaped with smooth valves, and contain a single polar capsule with an S-shaped polar filament, arranged in 13–16 polar filament coils, oriented longitudinally, with an irregular distribution on the polar capsule matrix. Spores measure 15.8 (14–17) μm in total length in lateral view, 7.9 (6–9) μm in width in apical view, with spore body length of 6.2 ± 0.4 (5–7) µm. The ellipsoidal polar capsule has two adjusted lateral folds 7.6 (6–8) µm long and 2 (2–3) µm wide. The new species is distinguished from other species of the genus based on spore morphometry and molecular data. The phylogenetic tree constructed using Maximum Likelihood and Bayesian Inference analysis of SSU rDNA sequence data supported the phylogenetic position of A. maamouni n. sp. among the species of Auerbachia Meglitsch, 1968 sequenced to date. Analysis of the SSU rDNA sequence data also supported the assumption that Auerbachia is closely related to members of the genera Coccomyxa Léger & Hesse, 1907, Zschokkella Auerbach, 1910 and Myxidium Bütschli, 1882, whose members inhabit the gallbladder of marine teleost fishes.     

First record of an actinosporean (Myxozoa) in a marine polychaete annelid

The marine polychaete Nereis (Hediste) diversicolor (Annelida) from shallow water in the Oresund, Denmark, was found to be infected with an actinosporean stage of a myxozoan parasite. The body length of the pyriform actinospore is 12-16 microm and its maximum width is 10-12 microm. The spore is triangular in apical view, with the 3 spherical polar capsules distally. The spore is without caudal processes. Eight spores develop in each pansporocyst. Free spores and pansporocysts were found in the musculature and parapodia but not in the intestine. The myxosporean stage in fish is unknown. This is the first record of an actinosporean stage in a marine polychaete, but because marine oligochaetes are rare, compared with polychaetes, the latter are believed to play an important role as invertebrate (alternate) hosts in marine myxozoan life cycles.     

Myxosporean parasites of the catfish,Clarias lazera (Valenciennes)

Summary Five new species of myxosporean were found in the catfish Clarias lazera (Val.) in Israel. These species are described as: Henneguya laterocapsulata n. sp. (cyst-like trophozoites in the skin), H. suprabranchiae n. sp. (cyst-like trophozoites in the suprabranchial respiratory organs), Sphaerospora inaequalis n. sp. (spores in the lumen of the kidney tubules), Myxidium clariae n. sp. (spores in the gall bladder) and Myxobolus heterofilamentatus n. sp. (spores in the kidney, spleen, liver, suprabranchial respiratory organ, gills, heart and urinary bladder). Their taxonomic affinities to other species are discussed. ac]19860407     

Ultrastructural studies of Henneguya rhamdia n. sp. (Myxozoa) a parasite from the Amazon teleost fish, Rhamdia quelen (Pimelodidae)

Henneguya rhamdia n. sp. is described in the gill filaments of the teleost fish Rhamdia quelen, collected from the Peixe Boi River, State of Pará, Brazil. This myxosporean produced spherical to ellipsoidal plasmodia, up to 300 microm in diameter, which contained developmental stages, including spores. Several dense bodies up to 2 microm in diameter were observed among the spores. The spore body was ellipsoidal (13.1 microm in length, 5.2 microm in width, and 2.5 microm in thickness) and each of the two valves presented a tapering tail (36.9 microm in length). These valves surrounded the binucleated sporoplasm cell and two equal ellipsoidal polar capsules (4.7 x 1.1 microm), which contained 10-11 (rarely 12) polar filament coils. The sporoplasm contained sporoplasmosomes with a laterally eccentric dense structure with a half-crescent section. Based on the data obtained by electron microscopy and on the host specificity, the spores differed from previously described Henneguya species, mainly in their shape and size, number and arrangement of the polar filament coils, and sporoplasmosome morphology.     

Microcotyle omanae n. sp. (Monogenea: Microcotylidae), a parasite of Cheimerius nufar (Valenciennes) (Sparidae) from the Arabian Sea

Microcotyle omanae n. sp. (Monogenea: Microcotylidae) is described from the gills of Cheimerius nufar (Valenciennes) (Sparidae) from the Arabian Sea. The new species closely resembles Microcotyle arripis Sandars, 1945, M. helotes Sandars, 1944, M. caudata Goto, 1984 and M. sebastis Goto, 1984, which have also been found in the Indo-Pacific. Microcotyle omanae n. sp. differs from M. arripis, M. helotes and M. caudata by its greater number of testes, from M. arripis, M. helotes by its greater length of the genital atrium, length/width ratio of the genital atrium and length of the eggs, and from M. helotes also in greater width of the clamps, from M. caudata and M. sebastis in its greater number of clamps and additionally from M. sebastis by its smaller genital atrial spines and clamps and by the ratio between length and width of the genital atrium. Moreover, the mature specimens of the new species have greater average body length than all above mentioned species. Correlations between 15 morphometric characters and body length are analysed in the new species, and their significance for species differentiation is discussed.     

Ortholinea nupchi n. sp. (Myxosporea: Ortholineidae) from the urinary bladder of the cultured olive flounder Paralichthys olivaceus,South Korea

A new myxosporean parasite, Ortholinea nupchi n. sp. (Myxozoa; Bivalvulida), was isolated from the urinary bladder of the olive flounder Paralichthys olivaceus cultured on Jeju Island, Korea. Mature spores were subspherical in the valvular and apical views and ellipsoidal in the sutural view. The spores measured 7.6 ± 0.5 μm in length, 6.7 ± 0.3 μm in thickness, and 7.3 ± 0.5 μm in width. Two pyriform polar capsules measured 3.2 ± 0.1 μm in length and 2.7 ± 0.1 μm in width and were located at the same level at the anterior half of the myxospores. The suture line was straight in the middle of the spores, and the surface ridges ranged between five and seven, forming an intricate pattern. The result of the 18S rDNA comparison showed ≤ 93.0% similarity with other Ortholinea species. The phylogenetic tree demonstrated that O. nupchi n. sp. was closest to O. auratae and clustered with oligochaete-infecting myxosporeans (OIM) having urinary system infection tropism. Based on the comparison of environmental and host factors in the phylogenetic groups of the OIM clade, we propose that the infection of O. nupchi n. sp. originated from marine oligochaetes.     

New species of Myxosporidia (Myxosporea: Cnidosporidia) from cottids (Abyssocottidae) and the oilfishes (Comephorus spp.) of Baikal Lake

Two new species of Myxosporidia, Myxidium baicalensis sp. n., Myxidium donecae sp. n. are described from the gall bladder of fishes from Baikal. Myxidium baicalensis sp. n. parasitising gobies Cyphocottus megalops, Asprocottus platycephalus, and other host species, while Myxidium donecae sp. n. parasitising Baikal oil fishes Comephorus baicalensis and C. dybowski.     

Bivalvulidan (Myxozoa: Myxosporea) parasites of damselfishes with description of twelve novel species from Australia's Great Barrier Reef

Bivalvulidan parasites from the gall bladder of 31 species of damselfishes (family Pomacentridae) were examined for their taxonomic identity and their relatedness to other species of myxozoans. This paper describes 11 novel ceratomyxid species and a novel Myxidium sp. Each species is characterized morphologically and small subunit (SSU) rDNA sequences were used in molecular phylogenetic analyses. Five pomacentrid species were found to harbour multiple infections of bivalvulidan species. One species of Ceratomyxa and Myxidium were found to infect more than a single species of damselfish. Phylogenetic analyses revealed there has been no radiation of ceratomyxids that can be associated with the fish host taxon and that Myxidium queenslandicus n.sp. was more closely related to Zschokkella mugilis and Ellipsomyxa gobii than other members of the genus Myxidium.     

Myxobolus cycloides on the swimbladder of chub Leuciscus cephalus: a controlled,host-specific localisation

Of 150 wild stock chub, Leuciscus cephalus L. captured in Lower Austrian watercourses, 112 revealed disc like plasmodia of Myxobolus cycloides Gurley, 1893 on the caudal chamber of the swim bladder. Other cyprinid species from the same waters lacked M. cycloides or other myxosporeans in this specific localisation. In chub, the intensity of infection (number of discs on the swim bladder) showed a logarithmic, age-dependent increase. The plasmodia of M. cycloides were situated in the connective tissue--mainly along blood vessels--and exhibited a delicate envelope of host tissue, thus forming a characteristic myxosporean cyst. Occasionally single trophozoites seemed to merge. A general process of fibroblast proliferation leading to encapsulation and degradation of the parasite was observed. This process was initiated by the formation of small multiple encapsulations within the spore containing trophozoid, before thickening of the outer cyst wall occurred. The general non-inflammatory course of the M. cycloides infection, and the obvious good health of the investigated chub suggest that this myxosporean in its host specific localisation cannot be regarded as a serious pathogen--on the contrary: parasite multiplication and degradation seemed to occur in a well-defined equilibrium controlled by the host fish.     

Myxosporea parasites in roach, Rutilus rutilus (Linnaeus), from four lakes in central Finland

Ten myxosporean species belonging to three families were found in roach, Rutilus rutilus (Linnaeus), obtained in 1985 and 1986 from four lakes in central Finland which are connected to each other, but differ in water quality. One of the lakes is polluted by paper and pulp mill effluent, two are eutrophic and one is oligotrophic and still in its natural state. Eight species were found in all the lakes. The most common species were Myxidium rhodei Léger, 1905, Myxobolus muelleri Bütschli, 1882 and Myxobolus pseudodispar Gorbunova, 1936 with prevalences varying between 66–80, 16–31 and 32–59%, respectively, in the four lakes. The largest difference in myxosporean prevalence between lakes was found in the case of M. pseudodispar infection, which was highly significantly lower in the polluted lake. The locations of the myxosporean species in the tissues of the fish were found to be species-specific. M. rhodei and M. muelleri being prevalent in the kidney and M. pseudodispar in the muscles.
No clear seasonal variation was found but a tendency for a decrease in infection with increasing age was recorded in the case of M. rhodei and M. pseudodispar .     

Relatedness of novel species of Myxidium Bütschli, 1882, Zschokkella Auerbach, 1910 and Ellipsomyxa Køie, 2003 (Myxosporea: Bivalvulida) from the gall bladders of marine fishes (Teleostei) from Australian waters

During a parasitological survey, Myxidium-like spores were identified in the gall bladders of marine fishes from Australian waters. This paper describes four novel species of Ellipsomyxa Køie, 2003, three novel species of Myxidium Bütschli, 1882 and six novel species of Zschokkella Auerbach, 1910 from teleosts from Australian waters using a combination of morphological, biological and molecular characters. Phylogenetic analyses showed a monophyletic relationship of all Ellipsomyxa spp. sequences with Sigmomyxa sphaerica (Thélohan, 1895) and Myxidium queenslandicus Gunter & Adlard, 2008 as sister species to the clade. The validity of genus Sigmomyxa Karlsbakk & Køie, 2012 is discussed. In phylogenetic analyses, the novel species of Myxidium fell within the ‘marine’ clade of Fiala (2006). However, the novel species of Zschokkella fell within the ‘freshwater’ clade of Fiala (2006) and formed a distinct clade with all other sequences of Zschokkella spp. from the gall bladder of marine fish and a sequence of a species of Myxobolus Bütschli 1882, also from the gall bladder of a marine fish. This is the second distinct marine lineage to emerge within the freshwater clade.