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Myxozoa is a class of the Phylum Cnidaria made up of endoparasites from aquatic habitats. The genus Ceratomyxa preferentially infects marine fish, with the gallbladder being the main site parasitized. This study aimed to describe a new species of Ceratomyxa found in this organ in Boulengerella cuvieri using morphological, morphometric characterization and phylogenetic analysis of 18S rDNA gene sequences. Specimens of B. cuvieri were collected, anesthetized, desensitized and biometric measurements were performed. The organs were analyzed under a stereomicroscope and fragments of internal organs were extracted for light microscopy analysis, preserved in 80% ethanol for 18S rDNA gene analysis and fixed in Davidson solution for histological processing. Free spores of Ceratomyxa were observed in the gallbladder, in plasmodia with wave-like movements, with the following dimensions: spore width (24.5 ± 0.4) µm, spore length (5.2 ± 0.3) µm, polar capsule width (1.8 ± 0.2) µm, polar capsule length (2.1 ± 0.3) µm, number of polar tubule turns (4-5) and 100% prevalence. Phylogenetic analysis confirmed that Ceratomyxa matosi n. sp. is a new species, grouped with other freshwater Ceratomyxa species from the Amazon, representing the second description of species of this genus in the state of Amapá.

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The Amazon is the largest river basin in the world and it is home to the greatest diversity of freshwater fish in the world. Mesonauta festivus is a cichlid popularly known as flag cichlid, widely distributed throughout South America. The diversity of parasites in fish from the Amazon region is still underestimated, due to the high fishes diversity. The Myxozoa class has a universal distribution, with some specimens being pathogenic to some fish. The aim of this work was to describe a new species of Hoferellus in M. festivus. The fish were collected in the lake region, municipality of Tartarugalzinho, in the state of Amapá, Brazil. The new species was found parasitizing the urinary bladder of M. festivus. Spores were 11.5 ±1.1 (10.4-12.6) µm long and 10.9 ±1 (9.9-11.9) µm wide, and polar capsules were equally sized, measuring 4.9 ±0.5 (4.4-5.4) µm long and 3.4 ±0.9 (2.5-4.3) µm wide, with a pyriform shape, convergent with the apical region of the spore. The polar filament was wound with 5 to 6 turns. Morphological, morphometric, molecular and phylogenetic analysis proved that it is a new species of Hoferellus in the Amazon region.

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This study undertook the first investigation of malacosporean infections in Neotropical fish. We used polymerase chain reaction detection with a primer set generally targeting known malacosporeans to assay for infection in the kidney of 146 fish in 21 species belonging to 12 families collected from two areas in the Amazon Basin. Infections were found in 13 fish variously belonging to seven species in six families and included the first identification of a malacosporean infection in cartilaginous fish (a freshwater stingray). Based on ssrDNA, all infections represented a single Buddenbrockia species (Buddenbrockia sp. E) that demonstrates an exceptionally broad range of fish species infected, and countered our expectations of high Neotropical malacosporean diversity. Infections were characterized at varying and often high prevalences in fish species but sample sizes were small. Ascertaining whether highly divergent malacosporeans have not been detected by current primers, and more comprehensive sampling may reveal whether malacosporeans are truly as species poor in the Amazon Basin as present data suggest. Our results prompt speculations about evolutionary scenarios including introduction via marine incursions and patterns of host use over time.

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The present study describes Henneguya tietensis n. sp. parasitizing Prochilodus lineatus (Valenciennes, 1837) from Brazil, through morphological and molecular analysis. Myxospores were found in the gill tissue of P. lineatus with a prevalence of 10%. The myxospores consisted of two elongate, elliptical shell valves each with a long, tapering caudal appendage. The morphology was consistent with Henneguya and the myxospore measured as follows (mean ± SD): total length 55.5 ± 2.1 µm, body length 16.2 ± 1.1 µm, body width 5.5 ± 0.1 µm, caudal appendages length 39.0 ± 2.0 µm. The polar capsules were 7.3 ± 0.2 µm long, 1.7 ± 0.2 µm wide and contained a polar filament coiled 11 to 13 turns. Histological analysis showed the plasmodia developing in the middle region of each gill filament and caused a focally extensive distension by forming a space-occupying mass within the gill filament. The ultrastructural analysis allowed the observation of the presence of mature myxospores throughout the plasmodium. Phylogenetic analysis with the SSU rDNA gene showed Henneguya tietensis n. sp. as a sister species of the subclade formed by Henneguya piaractus and Henneguya brachypomus that infect fishes of the genus Piaractus. The genetically closest species was H. piaractus, which showed a similarity of 82.4%. Using molecular and morphological characterization, the myxozoan parasite described herein represents a new species of the genus Henneguya.

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Species of the genus Ellipsomyxa Køie, 2003, parasitize mostly marine and brackish fish around the world. In the present study, we describe two novel species of Ellipsomyxa: Ellipsomyxa plagioscioni n. sp. parasitizing the gall bladder of Plagioscion squamosissimus (Sciaenidae), a freshwater fish but commonly found in brackish water in the Amazonian estuarine environment; and Ellipsomyxa paraensis n. sp. infecting Cichla monoculus (Cichlidae), a strictly freshwater fish. The host specimens were caught from the Amazon and Tapajós rivers, in the municipal region of Santarém, in the State of Pará, Brazil. The study was performed using a combination of morphological, biological, and SSU rDNA-based phylogeny, which suggested that marine transgressions of the Miocene epoch, in the central region of South America, were a pathway for the adaptation and radiation of these cnidarian parasites in the freshwater environment. Both disporic plasmodia and mature myxospores were found floating freely in the bile. Mature myxospores from both species were ellipsoidal in the valvular and sutural views, with thin smooth valves elongated in the direction perpendicular to the plane of the transverse sutural line. Ellipsomyxa plagioscioni n. sp. myxospores measured 11.1 (10.2-12.8) µm in length and 6.6 (5.6-7.6) µm in width. Two pyriform polar capsules discharging on opposite sides, some distance from both the sutural line and the spore ends, measured 3.8 (3.2-4.4) µm in length and 2.8 (2.3-3.3) µm in width, with 5-6 coil polar tubules. Ellipsomyxa paraensis n. sp. myxospores measured 11.5 (10.5-12.4) µm in length and 7.5 (6.6-8.6) µm in width. Two pyriform polar capsules which discharged on opposite sides some distance from both the sutural line and spore ends, measured 3.2 (2.1-3.9) µm in length and 2.6 (2.0-3.3) µm in width, with 2-3 coil polar tubules. Valvular protrusions were observed, associated with the tips of the polar capsules. Molecular analysis based on the SSU rDNA sequences indicated that the two novel Ellipsomyxa species were distinct from all other sequences deposited in the GenBank database. The phylogenetic trees clustered E. plagioscioni n. sp. as a basal species of a lineage of the marine/estuarine Ellipsomyxa, while E. paraensis n. sp. clustered together with other Amazonian species.

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This paper provides morphological and phylogenetic analyses of two new myxobolid species found infecting Piaractus brachypomus from the Amazon basin. The fish were caught in the Tapajós River, in the municipality of Santarém, in the state of Pará, Brazil. The plasmodial development of Henneguya brachypomus n. sp. occurred in the gill lamellae while Myxobolus pirapitingae n. sp. developed in the pyloric cecum. Morphological analyses did not identify inflammatory infiltrate for either species, but H. brachypomus n. sp. induced stretching of the epithelium, compression of the adjacent tissues, and displacement and deformation of the neighboring lamellae. The mature myxospores of H. brachypomus n. sp. were ellipsoid, with a length of 11.7-13.8 µm, a width of 4.0-4.6 µm, and a thickness of 3.5-4.3 µm. The polar capsules were elongated, with a length of 5.6-7.3 µm and a width of 1.3-2.0 µm, and each contained a polar filament with 8-9 coils. The caudal process was 40.5-48.1 µm long and the total length of the myxospore was 52.4-61.6 µm. Myxobolus pirapitingae n. sp. exhibited rounded mature myxospores measuring 10.0-11.1 µm in length, 7.0-7.6 µm in width, and 5.4-6.3 µm in thickness. The polar capsules were of equal size and occupied less than half the myxospore, measuring 3.5-4.0 µm in length and 2.0-2.6 µm in width, with each containing a polar filament with 6-7 coils. Phylogenetic analysis based on partial small subunit ribosomal DNA (ssrDNA) sequences showed that H. brachypomus n. sp. clustered as a sister species of Henneguya piaractus, while M. pirapitingae n. sp. was grouped in a sub-clade together with Myxobolus matosi and Myxobolus colossomatis.

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The aim of this was describe an infection by Kudoa orbicularis in freshwater catfish Trachelyopterus galeatus. A sample of 80 specimens of T. galeatus was collected in the municipality of Cachoeira do Arari, Marajó Island, in the state of Pará, Brazil. Pseudocysts were found in the muscle fibers of the epaxial and hypaxial regions of 85.0% of the specimens analyzed, reflecting a high infection rate. The pseudocysts contained spores that were pseudo-square in shape, with a mean length of 4.65 µm (range: 4.04-5.54) and mean width of 1.53 µm (1.56-1.74). Analyses on the morphology of the spores and a partial 934-bp sequence of the SSU rDNA gene confirmed that the microparasite was Kudoa orbicularis. This is the second record of this microparasite in a siluriform host in the Brazilian Amazon region.

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Abstract The aim of this was describe an infection by Kudoa orbicularis in freshwater catfish Trachelyopterus galeatus. A sample of 80 specimens of T. galeatus was collected in the municipality of Cachoeira do Arari, Marajó Island, in the state of Pará, Brazil. Pseudocysts were found in the muscle fibers of the epaxial and hypaxial regions of 85.0% of the specimens analyzed, reflecting a high infection rate. The pseudocysts contained spores that were pseudo-square in shape, with a mean length of 4.65 µm (range: 4.04-5.54) and mean width of 1.53 µm (1.56-1.74). Analyses on the morphology of the spores and a partial 934-bp sequence of the SSU rDNA gene confirmed that the microparasite was Kudoa orbicularis. This is the second record of this microparasite in a siluriform host in the Brazilian Amazon region.

Resumo O objetivo deste estudo foi descrever a infecção por Kudoa orbicularis em Trachelyopterus galeatus. Foram analisados 80 espécimes de T. galeatus capturados no município de Cachoeira do Arari, ilha de Marajó, estado do Pará, Brasil. A presença de pseudocistos nas fibras musculares das regiões epiaxial e hipoaxial em 85,0% dos exemplares analisados, mostra alto grau de infecção. Os pseudocistos continham esporos de formato pseudoquadrado, medindo 4,65 (4,04-5,54) µm de comprimento e 5,25 (4,78-5,98) µm de largura, com quatro cápsulas polares de tamanho iguais medindo 2,22 (2,05-2,32) µm de comprimento e 1,53 (1,56-1,74) µm de largura. Através das análises morfológicas dos esporos e molecular de uma sequência parcial de 934bps do gene SSU rDNA, confirma que o microparasito é Kudoa orbicularis, sendo este o segundo registro desse microparasito em hospedeiro da ordem Siluriformes da Amazônia brasileira.

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Ultrastructural and phylogenetic description of a fish-infecting myxosporean found infecting the gallbladder wall of the teleostean Eugerres brasilianus Cuvier, 1830, collected from the Atlantic coast near the city of Maceió (Alagoas State), Brazil. Groups of mature pseudo-conical myxospores, agglutinated forming pseudocyst structures, occurring in the mucosa of gallbladder were 5.2 ± 0.8 µm (4.5-6.0) (n = 30) long, 4.3 ± 0.6 µm (3.8-4.7) (n = 25) thick, and 2.9 ± 0.2 µm (2.7-3.2) (n = 25) wide. The two ellipsoidal polar capsules, 1.8 ± 0.4 × 1.2 ± 0.4 µm (n = 25), opened close to the sutural line, each containing an isofilar polar tubule. The latter consisted of a single coil with five to six turns, arranged obliquely to the axis of the polar capsule. This myxosporean parasite, while being morphologically similar to Sphaerospora spp., displays tissue tropism and phylogenetic relationships distinct from the latter. Bayesian inference (BI) and maximum likelihood (ML) analyses showed the parasite and two other related species clustering within the marine clade, more specifically within a subclade of the larger Kudoa (Multivalvulida) clade. Consequently, this atypical new myxozoan species was classified as Kudoa eugerres n. sp. and two other histozoic Sphaerospora spp. sensu lato were transferred to the genus Kudoa.

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The class Myxozoa is a group of spore-producing eukaryote organisms that parasitize both freshwater and marine fish. The multivalvulide myxosporidian parasites of the genus Kudoa infect primarily the musculature of the fish host, some species are producing enzymes (proteases) capable of digesting muscle fibers. In the present study, 50 specimens of the freshwater catfish Hypophthalmus marginatus were collected from the Tocantins River in Pará, Brazil, and were analyzed. Overall, 68% of these specimens presented infections by Kudoa parasite in the esophageal musculature. The morphology of these parasite was examined under light microscopy and nucleotide sequences of the SSU rDNA gene were obtained for phylogenetic analyses. The species formed numerous whitish pseudocysts containing square spores with rounded extremities in the apical view, and four polar capsules of equal size. In the phylogenetic analyses, Kudoa amazonica n. sp. was characterized as a sister taxon of another freshwater species, Kudoa orbicularis. The combination of morphological, morphometric, and molecular data obtained in the present study provided a conclusive diagnosis of Kudoa amazonica n. sp., which is clearly distinct from all other Kudoa taxa described to date.

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Henneguya guanduensis was originally described as a gill parasite of the Hoplosternum litoralle, a siluriform fish belonging to the Callichthyidae family. A study was undertaken with 58 specimens of H. litoralle taken from Batalha River in the state of São Paulo. The fish were collected and examined searching for lesions and/or myxosporean plasmodia. The prevalence of infection was 9.31% in the gills and 5.17% in the intestine. The mature spores had elongated bodies with polar capsules of inequal size and a caudal length greater than body length. Morphological characteristics identified the parasite as H. guanduensis. Molecular analysis of the SSU rDNA partials sequences resulted in a 1796 bp and 1712 bp for gills and intestine repectively, demonstrating significant genetic differences with previously described species of Henneguya and 99.7% similarity to each other when aligned. Phylogenetic analysis comparing the SSU rDNA sequence of H. guanduensis with closest species as indicated by BLASTn Max Score showed H. guanduensis as sister species of H. loretoensis in a subclade compose by species that parasites fishes from Amazon basin. This is the first report of the finding of Henneguya guanduensis spores in the intestine of Hoplosternum littorale.

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A new myxozoan species, Henneguya sp., is described based on material from skin of Cyphocharax modestus. Mature myxospores are were elongate and ellipsoidal, measuring 21.4 ±â€¯1.2 (19.4-23.2) µm in total length, 5.1 ±â€¯0.3 (4.5-5.8) µm in width, 11.9 ±â€¯0.5 (10.9-12.7) µm in body length and 9.6 ±â€¯0.7 (8.4-10.5) µm in length of the caudal process. The polar capsules were elongated and had unequal sizes, with length of 5.1 ±â€¯0.4 (4.5-6.0) µm and 5.6 ±â€¯0.4 (4.9-6.3) µm for smaller and larger respectively and width of 1.8 ±â€¯0.2 (1.4-2.0) µm. The larger polar capsule had 8 turns in polar filament while the smaller polar capsule had 5 turns in polar filament. The macroscopic analysis revealed the presence of large nodules, which were located before and after the dorsal fin of the hosts. The histopathological analysis showed the development of nodules filled with plasmodia, surrounded by loose connective tissue, developed in the dermis of the skin. Many cysts containing countless spores, as well as free spores, were located in the dermis and hypodermis of the hosts, causing the disorganization of the connective tissue that is responsible for the support. This is the first record of a Henneguya species in C. modestus.

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This paper describes 2 new myxosporean species, Henneguya lepturus sp. nov. and Thelohanellus lepturus sp. nov., simultaneously infecting the brain and spinal cord of Hypopygus lepturus Hoedeman, 1962 (Teleostei, Hypopomidae) from the Brazilian Amazon (Roraima State). Several spherical cysts of varying dimensions (up to 135 µm) were microscopically observed. The myxospores of H. lepturus sp. nov. measured 25.8 µm in total length, having an ellipsoidal body (12.4 × 6.4 × 2.2 µm) and 2 equal tapering tails (13.4 µm in length). Each of the 2 pyriform polar capsules measured 4.4 × 1.6 µm and possessed a polar filament coiled in 8-9 turns. The myxospores of T. lepturus sp. nov. were pyriform, formed by 2 equal valves (17.7 × 9.1 × 4.3 µm) surrounding a single polar capsule (10.9 × 3.5 µm) that had a coiled polar filament with 13-16 turns and a binucleated sporoplasm that contained several circular sporoplasmosomes. Molecular analysis of the small subunit (SSU) rRNA gene sequences of these 2 species were in agreement with the taxonomic classification derived from the ultrastructure of the myxospores. Histopathology of the host tissue showed degradation of the myelinated axons surrounding the cysts of both species, with the hosts displaying behavioural changes and erratic movements when observed in an aquarium.

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The Patagonian seabass Acanthistius patachonicus (Jenyns, 1840) (Serranidae) is a marine fish valued for commercial and sport fisheries from Argentina. We report a new myxosporean (Cnidaria: Myxozoa) infecting the urinary system of the Patagonian seabass from San Antonio Bay, San Matías Gulf, on the Atlantic Ocean. The mature myxospores were subspherical, 8.2-11.0 µm × 7.9-11.0 µm and 7.7-9.0 µm in thickness; two subspherical polar capsules, 2.4-3.8 µm × 2.3-3.6 µm, with 3 to 4 turns of the polar tubule; openings on different valves in almost opposite directions. Ornamented shell valves exhibited 17-20 concentrically organized surface ridges. SSU rDNA phylogenetics analyses placed the new species in the freshwater urinary tract clade, clustering in a clade formed by Myxobilatus gasterostei (Parisi, 1912), Acauda hoffmani Whipps, 2011, and other Ortholinea spp. Based on spore morphology, site of infection, and molecular data, we described this myxozoan as Ortholinea concentrica n. sp.

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During a survey on the myxosporean fauna of Rajiformes from the Atlantic coast of Argentina, in waters off Buenos Aires Province (34°-42°S; 53°-62°W), the gall bladders of 217 specimens belonging to seven species of skates, representatives of two families, were examined. As a result, three species of Chloromyxum Mingazzini, 1890, namely C. atlantoraji n. sp., C. zearaji n. sp. and C. riorajum Azevedo, Casal, Garcia, Matos, Teles-Grilo and Matos, 2009 were found infecting three endemic host species, the spotback skate Atlantoraja castelnaui (Arhynchobatidae), the yellownose skate Zearaja chilensis (Rajidae) and the Rio skate Rioraja agassizii (Arhynchobatidae), respectively. These species were described based on myxospore morphology and morphometry characterization, as well as by providing their small subunit ribosomal DNA (SSU rDNA) sequences. The SSU rDNA-based phylogenetic analyses showed that these three species constituted a well-established monophyletic subclade within the marine Chloromyxum clade, while branches subtending the other Chloromyxum species were poorly resolved or unresolved, independently of the host taxonomic identities (Carchariniformes, Myliobatiformes, Orectolobiformes, Pristiophoriformes, Rajiformes, Squaliformes and Torpediniformes) and/or host geographic distribution (Atlantic coast of Portugal, Atlantic coast of the USA, Australian waters or Mediterranean Sea). The possible causes of these discrepancies are discussed, providing new insights into the phylogeny of the marine Chloromyxum clade.

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Henneguya quelen n. sp. (Myxosporea) is described from the kidney of the silver catfish, Rhamdia quelen (Quoy & Gaimard, 1824), from Marajó Island. In all, 40% of the 57 silver catfish collected from the Paracauari River in the municipality of Salvaterra presented cysts in the kidney. The cysts were whitish, spherical, and 0.45 mm in diameter. The histological analyses revealed tubular renal compression and cellular degeneration in the area adjacent to the xenomas. The spores are ellipsoid, with well-marked valves, caudal projection, and two elongated polar capsules of equal size. The mature spores measure approximately 15.6 µm in length, with the caudal appendage split posteriorly; 24.3 µm in length, for a total spore length of 40.0 µm; and a width of 4.1 µm. The polar capsules are pyriform, 5.5 µm long and 1.7 µm wide. A phylogenetic analysis based on Bayesian inference confirmed that the specimens represented a new species, which was denominated Henneguya quelen n. sp.

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Ellipsomyxa arariensis n. sp. was found in the gallbladder of Pygocentrus nattereri Kner, 1858 and Pimelodus ornatus Kner, 1858 from the Arari River on Marajó Island in Pará, Brazil. The new species has disporous plasmodium that varies in size and shape, with ellipsoidal mature spores in the sutural view that have a curved suture line. The spores are 12.6 (12.0-13.4) µm in length and 7.3 (6.7-8.0) µm in width. The two polar capsules present in the spore are pyriform and of equal size, with subterminal openings that project in opposite directions. The polar capsules are 3.5 (3.4-4.0) µm long and 2.6 (2.5-3.2) µm wide. Based on the partial sequences of the SSU rRNA gene of the Ellipsomyxa arariensis n. sp. spores found in Pygocentrus nattereri Kner, 1858 (1325 bps) and Pimelodus ornatus Kner, 1858 (1240 bps), the new species is clearly distinct from all the other myxozoan sequences deposited in GenBank. Based on Bayesian inference and p distances, the new species belongs to the "Ellipsomyxa clade", together with all the other Ellipsomxa species, reinforcing the monophyletic status of this genus. Overall, the morphological data and the partial sequences of the SSU rRNA gene provide a conclusive diagnosis of Ellipsomyxa arariensis n. sp. as a species distinct from all the other Ellipsomyxa species described previously.

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During a parasitological survey of Astyanax altiparanae captured in the Mogi Guaçú river, Pirassununga, state of São Paulo, Brazil, a new species of myxozoa was observed infecting the kidney of 30 of 42 specimens. Plasmodia of the new myxozoa, referred to herein as Unicauda whippsi n. sp. were spherical and varied from 450 to 1000 µm in length. The mature spore was elongated and measured 11 ± 1.2 (10-12) µm long by 5.4 ± 0.6 (4.7-7.2) µm wide. Polar capsules of unequal length with the filament coiled 7-9 times and a unique caudal process characteristic of the genus Unicauda, were recorded. Phylogenetic analysis demonstrated that U. whippsi n. sp. clustered with members of the genus Unicauda and Myxobolus, confirming it's placement within the family Myxobolidae. This is the first record of a species of Unicauda infecting characiform fish, as well as the first registered occurrence of species of this genus in South America.

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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.

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We investigated the involvement of oligochaetes in the life cycles of fresh water myxozoan parasites in Brazil. In a fish farm in the State of Mato Grosso do Sul, we examined 192 oligochaetes and found that two (1%) released Aurantiactinomyxon type actinospores. We identified infected oligochaetes by morphology: both were Pristina synclites, from family Naididae. This is the first report of the involvement of this species in the life cycle of myxozoans. Small-subunit ribosomal DNA sequences of Aurantiactinomyxon type 1 (1882 nt) and Aurantiactinomyxon type 2 (1900 nt) did not match any previously sequenced myxozoan in the NCBI database, with the highest BLAST search similarities of 83% with Myxobolus batalhensis MF361090 and 93% with Henneguya maculosus KF296344, respectively, and the two aurantiactinomyxons were only 75% similar to each other (over ~ 1900 bases). Phylogenetic analyses showed that Aurantiactinomyxon type 1 had closest affinities with myxozoans from fish hosts in Order Characiformes, and Aurantiactinomyxon type 2 had affinities with myxozoans from fish of Order Siluriformes.

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