Mature Myxospores Research Articles

Growing diversity supports radiation of an Ellipsomyxa lineage into the Amazon freshwater: Description of two novel species parasitizing fish from Tapajós and Amazon rivers

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.

A new Myxobolus (Cnidaria: Myxosporea) infecting the ornamental catfish Corydoras schwartzi from the Purus River in Brazil

A new microscopic cnidarian is described, infecting five of thirty (16.6%) specimens of Corydoras schwartzi caught in the Purus River, State of Amazonas, Brazil. Histological analysis showed that cyst development occurred in the serosa layer of the intestine. Mature myxospores are ovoid in body shape in frontal view, 22.4 ± 0.3 μm in total length and 16.3 ± 0.1 μm in width. Internally, two aubergine-shaped, elongate symmetrical polar capsules occupy more than half the length of the spore, 14.3 ± 0.2 μm in length and 6.5 ± 0.1 μm in width. Ultrastructural analysis provided evidence of five polar filament coils inside the polar capsule and binucleated sporoplasm containing a moderate number of sporoplasmosomes. The valvogenic cells abutting each other form a sutural ridge and frequently a thin layer of homogeneous material separates the cells. The outer surface of the myxospore valves is smooth, with no evidence of formation of ridges in the valves. Immature myxospores in various stages of development were observed. This study is the first report of a myxosporean parasitizing C. schwartzi and the first report of a myxosporean infection in the intestine of an ornamental fish from South America.

Ceratomyxa mennani n. sp. (Myxosporea: Bivalvulida) parasitizing the gallbladder of the dusky grouper Epinephelus marginatus (Serranidae) from Tunisian waters.

Ceratomyxa mennani n. sp. is a new coelozoic Ceratomyxa species found in the gallbladder of Epinephelus marginatus from the Gulf of Tunis, Tunisia. Mature plasmodia were disporic, ovoid in shape measuring 9-12μm in width and 11-14μm in length. Mature myxospores were slightly crescent-shaped with almost straight posterior margin, measuring 5.8 ± 0.2 (5.4-6.1) μm in length and 12.7 ± 0.3 (11.9-13.0) μm in thickness. The two valves were unequal with rounded ends. Polar capsules were spherical, equal in size with 2.1 ± 0.2 (1.9-2.6) μm in diameter. The binucleated sporoplasm filled the entire cavity of the myxospore. Molecular analysis of SSU rDNA sequences indicated that C. mennani n. sp. was distinct from all other Ceratomyxa sequences in GenBank. Phylogenetic analysis revealed that C. mennani n. sp. clustered with Ceratomyxa species infecting Epinephelinae fishes. Seasonal prevalence of infection over oneyear was significantly higher in winter and the lowest in autumn. This is the third report of Ceratomyxa species infecting the gallbladder of Epinephelus marginatus from Tunisia and the first study to include molecular data.

Novel myxosporean species parasitizing an economically important fish from the Amazon basin.

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 11.7-13.8μm, a width of 4.0-4.6μm, and a thickness of 3.5-4.3μm. The polar capsules were elongated, with a length of 5.6-7.3μm and a width of 1.3-2.0μm, and each contained a polar filament with 8-9 coils. The caudal process was 40.5-48.1μm long and the total length of the myxospore was 52.4-61.6μm. Myxobolus pirapitingae n. sp. exhibited rounded mature myxospores measuring 10.0-11.1μm in length, 7.0-7.6μm in width, and 5.4-6.3μm in thickness. The polar capsules were of equal size and occupied less than half the myxospore, measuring 3.5-4.0μm in length and 2.0-2.6μm 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.

Characterization of Myxidium spinibarba sp. nov. (Cnidaria, Myxosporea, Myxidiidae) from Spinibarbus sinensis (Bleeker, 1871) in Chongqing China.

In the present study, we described a new species of Myxidium Bütschli, 1882, obtained from the gallbladder of Spinibarbus sinensis (Bleeker, 1871) from the Jialing River in Chongqing, China. Myxidium spinibarba sp. nov. was identified based on morphological and SSU rDNA sequence data. The mature myxospores were fusiform in valvular view and ovoid in sutural view, with somewhat protrusive poles and mean dimensions (all in μm) of 11.8 ± 0.5 (10.6-12.4) in length and 6.1 ± 0.5 (5.5-7.2) in width. The polar capsules were pyriform and equal in size with mean dimensions of 3.6 ± 0.4 (3.0-4.4) in length and 3.0 ± 0.2 (2.7-3.2) in width. The new species was distinct from related species of Myxidium in its morphology and molecular characteristics. Phylogenetic analysis indicated the clustering of species based on the presence or absence of valvular striations. Moreover, myxospore morphology, rather than the host environment, played an important role in the partial phylogenetic clustering.

A rare bird of Czechia: Case of homozygous female Fabry disease patient

A new myxozoan species belonging to the genus Henneguya was isolated from the serous membrane of the visceral cavity of the hognosed catfish Brochis multiradiatus from Peruvian Amazon. Whitish plasmodia, macroscopically visible, were found in four of the thirty examined fishes. Mature myxospores were ellipsoidal in shape in frontal view and had a total length of 44.5 ± 0.6 μm (43.9–45.1), spore body measured 18.7 ± 0.9 μm (16.8–19.6) in length, 7.1 ± 0.2 μm (6.6–7.4) in width and 5.5 ± 0.3 μm (4.9–5.6) in thickness. The two polar capsules were elongated and equal in size, measuring 9.1 ± 0.1 μm (8.8–9.4) in length and 1.7 ± 0.1 μm (1.6–1.8) in width, occupying half of the myxospore body. Polar tubules coiled in 10–11 turns perpendicular to the long axis of the polar capsule. The caudal appendage was not bifurcated and measured 25.8 ± 0.6 μm (24.7–26.5) in length. The sequencing of the 18S rDNA gene resulted in 1400 bp and this sequence did not match any of the myxozoans available in GenBank. Phylogenetic analysis placed the new species in a well-supported subclade of Henneguya spp. infecting callichthyid fishes, with Henneguya loretoensis being the closest species. This study is the first description of a myxozoan species, Henneguya multiradiatus n. sp. from a fish of the genus Brochis.

Taxonomy, phylogeny and host-parasite interaction of two novel Myxobolus species infecting Brycon orthotaenia from the São Francisco River, Brazil

Two new Myxobolus species were described infecting Brycon orthotaenia from the São Francisco River, in the state of Minas Gerais, Brazil. From a total of 39 B. orthotaenia collected, two specimens (5.1%) exhibited infection of the ovary and 12 specimens (30.8%) displayed infection of the liver. The plasmodia of both Myxobolus species were white and spherical measuring around 1 mm in length. The plasmodium found in the ovary showed mature myxospores, which were oval shaped from the frontal view and measured 9.2–11.0 (9.8 ± 0.4) μm in length, 5.9–6.9 (6.5 ± 0.3) μm in width and 4.6–5 (4.9 ± 0.1) μm in diameter. The two polar capsules were the same size and measured 3.9–6.2 (4.7 ± 0.5) μm in length and 1.8–2.4 (2.1 ± 0.2) μm in width. The polar tubules had 9 coils. The plasmodium found in the liver showed mature myxospores which were ellipsoidal in shape from the frontal view and measured 10.0–11.4 (10.7 ± 0.5) μm in length, 7.3–8.6 (8.1 ± 0.4) μm in width and 5.3–7.0 (6.8 ± 0.4) μm in diameter. The two polar capsules were the same size and measured 4.2–5.4 (4.9 ± 0.3) μm in length and 1.9–2.9 (2.7 ± 0.3) μm in width. The polar tubules had 8 coils. Ultrastructural analysis revealed an asynchronous sporogenesis process, with young developmental myxospore stages more often found in the periphery of the plasmodium and mature myxospores in the centre of the plasmodium. The plasmodial wall was formed by a single membrane which was not surrounded by a layer of host tissue. A thick layer of fibrous material was found in the peripheral ectoplasm close to the plasmodial wall of the plasmodium found in the ovary. Phylogenetic analysis based on the small-subunit ribosomal DNA – ssrDNA sequences and using the closest myxozoan sequences to each one of the species studied here based on previous GenBank data and Henneguya/Myxobolus/Thelohanellus species parasitizing fish from South American, revealed that the new species are grouped in a subclade together with other Myxobolus species parasitizing bryconid hosts.

An Optimized Protocol for Myxosporidia (Cnidaria: Myxosporea) DNA Extraction for Molecular Studies

Myxosporidia constitute a major group of fish parasites which have a significant negative impact on wild and cultured fish. The used of DNA in Myxosporidia studies has progressed rapidly over the last twenty years, especially in their identification and characterization as well as determination of species diversity and investigation of their evolutionary relationships. Extraction and isolation of pure and high quality DNA are essential for any molecular study, but constitute a challenge for many laboratories especially in low and middle income countries. Myxosporidia plasmodia filled with mature myxospores were isolated from different tissues of Labeo batesii Boulenger, 1911. DNA from myxosporidia myxospores were extracted using a Livak optimized DNAs extraction protocol. Four particular phases of the original protocol were optimized. Yield and absorbance ratios of extracted DNA were determined using spectrophotometer. DNA samples were used as template for the amplification of the 18S rDNA region and amplicons resolved on 1.5% agarose gel for determination of fragment sizes and purity evaluation. The concentration of extracted DNA from all Myxosporidia species ranged from 4.6 to 26 ng/μl with purity indices ranging from 1.88 to 2.12. We successfully amplified the 1050 bp DNA fragment as targeted. The intensity, thickness and clarity of the bands were evidences of non-degradation of DNA. The optimized Livak protocol is simple, low-cost and manageable. Regarding the quantity, purity and quality of extracted DNA, the optimized Livak protocol is highly recommended for Myxosporidia studies.

Morphological and molecular identification of Myxobolus parakoi sp. nov(Myxozoa: Myxobolidae), from Cyprinus carpio in Chongqing China.

During an ongoing investigation into the myxosporean diversity of common carp in Chongqing, China, Myxobolus parakoi sp. nov. was found to infect the gill lamellae of Cyprinus carpio (Linnaeus, 1758). Both morphological and SSU rDNA data revealed that M. parakoi sp. nov. was distinct from other myxosporeans. Mature myxospores of M. parakoi sp. nov. were pyriform in the frontal view. The spores were 15.98 ± 0.78 (14.59-17.72) μm in length and 7.84 ± 0.78 (6.66-9.75) μm in width. The two polar capsules were pyriform and equal in size, exhibiting 8.72 ± 0.50 (7.76-9.92) μm in length and 3.03 ± 0.23 (2.63-3.56) μm in width. Polar filaments within the polar capsules were coiled with 11 or 12 turns. Phylogenetic analysis revealed that M. parakoi sp. nov. and Myxobolus koi (FJ710800) were clustered together, forming a sister subclade with Myxobolus tanakai. This study also implied that the morphology of the myxospores was generally correlated with their phylogenetic relationship, while such correlation was not strong or consistent.

Morphological and Molecular Identification of a Novel Species, Ceratomyxa siganicola n. sp. (Myxozoa: Ceratomyxidae) from Siganus fuscescens, in East China Sea

Ceratomyxa Thélohan, 1892 is one of the largest genera under Myxosporea Butschli, 1881, and has a worldwide distribution, but little attention has been paid to myxosporean parasites from the Chinese seawaters, East China Sea. Morphology and molecular biology methods were combined for species identification and phylogenetic analysis. A new coelozoic myxosporean species, Ceratomyxa siganicola n. sp., was found to infect the gallbladder of Siganus fuscescens (Houttuyn, 1782) (Perciformes, Siganidae) from coastal waters of Xiamen, East China Sea, China. Mature myxospores of the novel species exhibited the morphologically typical features of the genus Ceratomyxa. They were slightly crescent shaped with rounded ends, measuring 5.6 ± 0.5 (4.8-6.5)μm in length and 19.1 ± 1.8 (16.0-22.1)μm in thickness. The posterior angle was slightly convex to straight and measured 177.1 ± 0.5 (175.2-178.4)°. Spore valves were slightly unequal and smoothly ovoid in the lateral view. Two polar capsules were spherical, equal in size and measured 2.7 ± 0.2 (2.1-3.0)μm in diameter. The 18S rDNA sequence of C. siganicola n. sp. was unique among all myxozoans, and the highest similarity was 97.4% with Ceratomyxa barnesi. Phylogenetic analysis showed that C. siganicola n. sp. was clustered within the clade of siganid ceratomyxids. The present results also indicated that the species radiation of Ceratomyxa occurrednot only within host affinity but also within locality.

Morphological and molecular aspects of Ceratomyxa ghannouchensis n. sp. and C. pallida Thélohan 1894 infecting the bogue, Boops boops (l.)

ABSTRACTWe report herein the molecular and morphological characteristics of two myxozoan parasites, Ceratomyxa ghannouchensis n. sp. and Ceratomyxa pallida Thélohan, 1894 infecting the gallbladder of the bogue, Boops boops (Linnaeus, 1758) in the Gulf of Gabès off the Tunisian coast. Mature myxospores of C. ghannouchensis were stubby with a convex anterior end and almost straight to slightly concave posterior one. Mature myxospores measured 5.8 ± 0.4 (5–7) µm in length and 11.7 ± 0.3 (11–13) µm in thickness. Valves were unequal in size with one occasionally tapering to a greater degree than the other. The polar capsules were equal in size, spherical in shape and measured 2 ± 0.2 (1.8–2.8) µm in diameter. Infection with C. pallida occurs as spherical to elongated mono-, di- or trisporic plasmodia floating in the bile. Mature myxospores were crescent-shaped with two symmetrical shell valves with rounded edges. The myxospores measured 6 ± 0.5 (5–7) µm in length and 28.5 ± 2.5 (26–33) µm in thickness. The polar capsules were spherical, equal in size and measured 3 ± 0.3 (2.7–3.3) µm in diameter. Based on the SSU rDNA partial sequence, C. ghannouchensis n. sp. and C. pallida appeared in the same subclade with Ceratomyxa leatherjacketi and Ceratomyxa tunisiensis.www.zoobank.org/urn:lsid:zoobank.org:pub:0DE35680-A3C9-45BA-B29B-0B7462CA7A43

Morphological and molecular characterization of Myxobolus dibombensis sp. n. (Myxozoa: Myxobolidae), a parasite of the African carp Labeobarbus batesii (Teleostei: Cyprinidae) from Dibombe River, Cameroon.

Myxobolus dibombensis sp. n. (Cnidaria: Myxosporea: Bivalvulida) is described from the fins of the African carp, Labeobarbus batesii, based on morphological and molecular data. Prevalence of infection was 51.9% (67/129). Ovoid to spherical cyst-like plasmodia were found in the intrasegmental region and among the fin rays. No pathological changes were found in the fish host tissue surrounding the cyst-like plasmodia. Mature myxospores were ovoid in frontal view and lenticular in lateral view, with slightly truncated anterior and rounded posterior ends. Myxospores measured 16.8 (15.8-18.0) μm long and 11.4 (10.0-13.0) μm wide. There was a triangular intercapsular appendix measuring 3.8 (2.6-4.5) μm long. Polar capsules were ovoid and slightly unequal in size, occupying approximately one-third of the myxospore length. The larger polar capsule measured 7 (6-8) μm long and 3.6 (3-4) μm wide, while the smaller one measured 5.8 (4.8-7.0) μm long and 3 (2-4) μm wide. The larger polar capsule contained nine to 11 filament coils, whereas the smaller one contained seven to nine coils. SSU rDNA gene sequence of M. dibombensis sp. n. did not match any sequences available in the GenBank. The similarity with available Myxobolus spp. sequences ranged from 65 to 81%. The novel species clustered with M. algonquinensis, which infects the cyprinid Luxilus cornutus from Canada.

Morphological and molecular characterization of the muscle-infecting myxosporean Myxobolus xinyangensis sp. nov. from Abbottina rivularis in China

During an environmental assessment on the Huang River in Xinyang City (Henan Province, China), a novel Myxobolus species (Myxozoa: Myxobolidae) was found infecting the trunk muscle of Chinese false gudgeon Abbottina rivularis Basilewsky, 1855 (Gobioninae, Cyprinidae). Plasmodia of the new myxozoan, nominated herein as Myxobolus xinyangensis sp. nov., are round and yellowish, symmetrically and bilaterally located dorsal to the openings of the 2 opercula, and measure about 4.5 mm in diameter. The mature myxospores are orbicular in frontal view and fusiform in sutural view, with slightly tapered anterior end and rounded posterior end, and measure 9.4 ± 0.5 (8.7-10.6) µm long, 8.6 ± 0.6 (7.3-9.5) µm wide and 6.4 ± 0.3 (5.8-7.1) µm thick (mean ± SD, range). The ratio of spore length to spore width is close to 1. Two slightly unequal pyriform polar capsules, with tapering anterior ends and rounded posterior ends, measure 5.6 ± 0.67 (4.3-6.8) µm long and 3.0 ± 0.3 (2.4-3.6) µm wide, present as a figure 8 in the anterior part of spores and tightly converge at the top end of spores. Polar filament coils show 4 to 5 turns and are situated perpendicularly to the longitudinal axis of the polar capsules. No intercapsular appendix or sutural folds at the posterior end of spores were observed. The obtained partial small subunit ribosomal DNA sequence did not match any available data in GenBank and showed the highest sequence identity (93%) with 2 cyprinid trunk muscle-infecting Myxobolus species, M. pseudodispar and M. klamathellus. Phylogenetic analysis clearly showed that M. xinyangensis sp. nov. clustered within a cyprinid trunk muscle-infecting Myxobolus subclade at the basal position, but as an independent branch which was a possible reflection of its distinct myxospore morphology. This is the first record of infection of Myxobolus species in the trunk muscle of Abbotina fish.

Skin nodules associated with parasitism with Henneguya sp. (Cnidaria: Myxosporea) in the neotropical fish Cyphocharax modestus

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 ± 1.2 (19.4–23.2) μm in total length, 5.1 ± 0.3 (4.5–5.8) μm in width, 11.9 ± 0.5 (10.9–12.7) μm in body length and 9.6 ± 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 ± 0.4 (4.5–6.0) μm and 5.6 ± 0.4 (4.9–6.3) μm for smaller and larger respectively and width of 1.8 ± 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.

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.

Ortholinea concentrica n. sp. (Cnidaria: Myxozoa) from the Patagonian seabass Acanthistius patachonicus (Jenyns, 1840) (Perciformes: Serranidae) off Patagonia, Argentina.

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, 8.2-11.0μm × 7.9-11.0μm and 7.7-9.0μm in thickness; two subspherical polar capsules, 2.4-3.8μm × 2.3-3.6μm, 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.

Molecular phylogeny of the gill parasite Henneguya (Myxosporea: Myxobolidae) infecting Astyanax lacustris (Teleostei: Characidae) from fish farm in Brazil

Molecular data of Henneguya chydadea Barassa, Cordeiro and Arana, 2003, found in the gill filaments of Astyanax lacustris bred in fish farm in the State of Mato Grosso do Sul, Brazil was obtained in order to estimate their phylogenetic position among other platysporines myxosporean. The prevalence of the parasite was 28.1% and the range intensity was 1–3 plasmodia per fish. The shape and measurements of mature myxospores were consistent with the characteristics previously defined to H. chydadea. The SSU rDNA sequence of the myxospores of H. chydadea resulted in a total of 1405 nucleotides, and this sequence did not match any of the myxozoan available in the GenBank. Phylogenetic analysis showed H. chydadea within the clade of histozoic myxosporeans and closed together with Henneguya rotunda and Myxobolus pantanalis reported in the gill arch and fins and gill filaments of Salminus brasiliensis respectively. Nonetheless, the SSU rDNA sequences of H. chydadea, H. rotunda and M. pantanalis have only 85.2% and 84.4% similarity, respectively. This is the first molecular study of a Henneguya species that parasitizes a fish belonging to the genus Astyanax in South America. The importance of myxosporeans introduction to new locations along with infected cultured host is emphasized.

Ultrastructural and molecular characteristics of Kudoa crenimugilis n. sp. infecting intestinal smooth muscle of fringelip mullet Crenimugil crenilabis in the Red Sea.

This study describes infection of intestinal smooth muscle in fringelip mullets Crenimugil crenilabis with Kudoa crenimugilis n. sp. Of 30 individuals sampled from the Red Sea off Saudi Arabia, 6 (20%) were infected. Ovoid plasmodia (279-412 × 157-295 µm) in the smooth muscle of the intestine were packed with only mature myxospores with 4 valves. Specifically, light and transmission electron microscopy revealed quadrate myxospores with 4 equal, rounded, spore valves uniting at thin delicate suture lines. The mature myxospores were 8 (7-9) µm long, 5.2 (5-6) µm thick and 7.8 (7-8) µm wide. The 4 polar capsules were equal-sized, elliptical to ovoid, and measured 5 (4-5) µm long and 2 (1.5-3) µm wide, possessing 2 filament coils. The sporoplasm was uninucleated and composed of a primary cell enveloping a secondary cell. The parasite had a significant histopathological impact since the developing plasmodia replaced normal muscle tissue and was associated with the myolysis of local muscle fibres and the inflammatory infiltration of lymphocytes and macrophages. The partial sequences of the 18S and 28S rDNA showed that K. crenimugilis n. sp. has the highest level of nucleotide similarity with K. ciliatae (98.46 and 94.11%, respectively) and K. cookii (97.51 and 92.11%, respectively), both of which have previously been reported from the intestines of their host fish. Phylogenetic analysis revealed that K. crenimugilis consistently clustered with these other 2 intestinal Kudoa species in a well-supported subclade, confirming the evaluative association between Kudoa species infecting the same organs.

Identification of a new myxosporean parasite Thelohanellus indiana n. sp. (Myxosporea: Myxobolidae) isolated from three major organs of goldfish, Carassius auratus L. highlighted with its morphological and SSU rDNA sequence based molecular description

Fish mortality and poor growth in surviving fish contribute substantial losses to the ornamental fish farms of India and revealed an infection of a new myxosporidian parasite Thelohanellus indiana n. sp. which has become one of the most important limiting factors for successful aquaculture management. The parasite infects Carassius auratus, an Indian goldfish, described on the basis of myxospores morphology and amplification of a part of 18 S rDNA gene. Three major attaching site of fish body have been explored for showing the location of attachment for the parasites. The whitish cysts of the parasites are about 2.5–3.5 mm contains large amount of lemon shaped mature myxospores measuring 12.1–15.2 (13.8) × 7.5–8.8 (8) μm. A single round or elliptical polar capsule located only at the anterior pole of the spore having 6.2–7.2 (6.8) × 3.3–4.7 (4.0) μm in diameter. The morphological characters have been assessed by both the light and scanning electron microscope. The most differentiating feature from closely related species was carried out by morpho-taxonomic affinities with previously described species which are tremendously supported by molecular taxonomy by partial sequencing of the 18 S rDNA gene resulted in a total of 2101 bp fragment of newly obtained SSU rRNA gene sequence of the new species which exhibit 79–91% homogeneity with other closely related species available in GenBank. The BLAST search of Thelohanellus sp. did not matches with any available sequences in GenBank and the phylogenetic analysis revealed that the novel species were sister to T. habibpuri and T. caudatus, in the Thelohanellus clade and form a closest neighboring branch as a subclade in phylogenetic tree from which the new Thelohanellus parasite is being placed. Both the branches are originating from monophyletic clade that are strongly supported by bootstrap values which indicate clearly about independent position of T. indiana n. sp.

Myxobolus imparfinis n. sp. (Myxozoa: Myxosporea), a new gill parasite of Imparfinis mirini Haseman (Siluriformes: Heptapteridae) in Brazil.

A new species of myxozoan, Myxobolus imparfinis n. sp. is described based on material from the gills of Imparfinis mirini (Haseman) (Heptapteridae). Mature myxospores are round, measuring 7.1-8.4 (7.9 ± 0.3) μm in length, 4.5-6.2 (5.5 ± 0.5) μm in width and 3.1-4.2 (3.7 ± 0.3) μm in thickness. The polar capsules are of unequal size, the larger polar capsule measuring 3.4-4.5 (3.9 ± 0.3) μm in length and 1.4-2.0 (1.7 ± 0.1) μm in width and the smaller capsule measuring 3.1-3.8 (3.4 ± 0.2) μm in length and 1.2-1.8 (1.5 ± 0.2) μm in width. The polar filament presents 6-7 coils. Spores had a prevalence of infection of 75% (6/8). In histological analyses we detected the development site of spores in primary filaments, in afferent branchial artery, thus classifying the type of infection to the filamental type and vascular subtype. The phylogenetic analyses of a dataset including species Myxobolus Bütschli, 1882 and Henneguya Thélohan, 1892 from South America recovered M. imparfinis n. sp. as a sister species of Myxobolus flavus Carriero, Adriano, Silva, Ceccarelli & Maia, 2013. To our knowledge, this is the first record of a myxozoan species parasitising I. mirini.