First report of Kudoa species in the somatic muscle of the Japanese parrotfish Calotomus japonicus (Scaridae) and a description of Kudoa igami,n. sp. (Myxozoa: Multivalvulida)

Three species of the Kudoid parasite (Myxozoa: Multivalvulida) were observed in the somatic muscle of Japanese parrotfish Calotomus japonicus caught off the coast of western Japan. All three species formed pseudocysts in myofibers and caused subclinical infections. The three Kudoa species were distinguished by spore morphology, as well as their 18S and 28S rDNA sequences. We identified a previously undescribed taxa Kudoa igami n. sp. with spores that were stellate with rounded peripheral edges and five to six polar capsules (prevalence 29.3 %). Kudoa igami n. sp. were morphologically most similar to Kudoa neothunni but were distinguishable by a more rounded shape in the apical view. Molecular analyses demonstrated that the K. igami n. sp. is closely related to Kudoa thalassomi; however, the similarity in the 28S rDNA sequence was <96 % and the spore morphology was different. We found Kudoa thalassomi in one sample (prevalence 2.4 %), which is a new host and geographical record for this species. Kudoa lateolabracis, which causes postmortem myoliquefaction in Chinese sea bass Lateolabrax sp. and olive flounder Paralichthys olivaceus was found in Japanese parrotfish (prevalence 41.5 %) for the first time, but did not cause myoliquefaction. We also expanded the host record for the brain-infecting Kudoa yasunagai (prevalence 94.1 %). In addition, an unidentified microsporidia was observed in the somatic muscle (prevalence 23.3 %).     

Henneguya nagelii n. sp. (Myxozoa: Myxobolidae) in Cyphocharax nagelii (Steindachner, 1881) (Teleostei: Characiformes: Curimatidae) from the Peixe’s River, São Paulo State, Brazil

A new species of Myxosporea, Henneguya nagelii n. sp., is described parasitizing the gills of Cyphocharax nagelii collected from Peixe’s River, São Paulo State, Brazil. Among the fish examined, 16.7 % had gills parasitized by myxosporeans. The plasmodia were white, round, or oval and measured 150–250 μm. The mature spores were fusiform and had smooth wall. The spores measurements were the following: total length, 34.5?±?4.2 (26.4–39.9)?μm; body length, 12.0?±?0.5 (11.2–11.9)?μm; body width, 4.9?±?0.3 (4.4–5.5)?μm; and caudal process length, 22.4?±?4.0 (14.7–27.3)?μm. The polar capsules were elongated and of unequal size, with lengths of 4.9?±?0.4 (4.0–5.9)?μm and 5.2?±?0.4 (4.6–6.0)?μm for the longest and shortest axes, respectively. Capsule width was 1.8?±?0.2 (1.5–2.2)?μm. Each capsule contained a polar filament with six to eight turns. There was no mucous envelope or iodinophilous vacuole. Morphometric differences between this parasite and other species of the genus Henneguya indicated that the parasite observed in C. nagelii is a new species. This is the first species of Myxosporea described in Peixe’s River.     

Some pathophysiological insights into ovarian infestation by <Emphasis Type="Italic">Myxobolus</Emphasis> sp. (Myxozoa: Myxosporea) in <Emphasis Type="Italic">Clarias gariepinus</Emphasis> (Clariids: Silurids) from Bénin (West Africa)

Mature female specimens of the catfish Clarias gariepinus originating from Ouémé River (Benin) were investigated into ovarian myxozoan parasites. Spores of Myxobolus sp. (Myxozoa: Myxosporea) were found encrusted in the whitish color oocytes which present fat dot aspect in the gonads. The pathological investigation by electron microscopy revealed that maturation and multiplication of spores induced lytic action, deformation and dysfunction of the oocyte internal structures. No host inflammatory reaction was observed, while yolk, lipid, mitochondria, and other oocyte components were degenerated inducing empty area in the oocyte and could lead to castration in case of wide infestation. The mean prevalence was 19.79 %. No significant difference was observed within seasonal prevalence (χ²?=?1.771; df?=?3; p?>?0.05). Though the host length classes ranging from 35 to 39 cm and 40 to 45 cm were more infected, difference was not significant (χ²?=?2.273; df?=?4; p?>?0.05) within them. The spores are ovoid in shape with two polar capsules which are equal in size, pyriform, and converging in anterior part of spore with four to five polar filament turns. Spore body are (11.47?±?0.67)?×?(8.19?±?0.52)?μm length by width while polar capsule size are (4.24?±?0.25)?×?(3.07?±?0.28)?μm and located in the first third portion of the spore. The molecular approaches are still running for accurate identification of this parasite.     

Kudoa septempunctata n. sp. (Myxosporea: Multivalvulida) from an aquacultured olive flounder (Paralichthys olivaceus) imported from Korea

A new myxosporean species, Kudoa septempunctata n. sp. (Myxosporea: Multivalvulida), is described from the trunk muscles of an aquacultured olive flounder (Paralichthys olivaceus) imported from Korea. This species formed pseudocysts in the myofiber without inflammatory reactions, and the infection was not evident macroscopically. Spores of the new species were irregularly stellate in apical view, with the majority having seven unequal valves, each with a polar capsule of variable size (the remaining spores had six valves and polar capsules). The spores had dimensions of: width 11.8 (11.1–13.1); thickness 9.4 (8.9–10.0); length 8.5 (7.9–8.9); polar capsule length 4.6 (3.7–5.3); and polar capsule width 2.4 (2.2–2.8; mean with range in parentheses; n = 10; all measurements in micrometers). Scanning electron microscopy of the spores revealed unequal positioning of the seven valves without a definite center, rounded posterior ends of valves, and tiny projections at the apex of each valve. The small subunit ribosomal RNA gene (SSU rDNA) sequence of the new species was closely related to Kudoa spp. with five or more valves, particularly Kudoa thalassomi (97.6% identity) recorded from the trunk muscles of a moon wrasse (Thalassoma lunare) around the Australian continent. However, the latter species has six valves with a pointed edge and six polar capsules of a uniform size. The new species was also distinct from all presently known Kudoa spp. with seven valves and polar capsules, i.e. Kudoa yasunagai and Kudoa lethrini, regarding tissue tropism (trunk muscles versus brain), spore shape or external appendages, and SSU rDNA sequence.     

Morphology and host–parasite interaction of <Emphasis Type="Italic">Henneguya azevedoi</Emphasis> n. sp., parasite of gills of <Emphasis Type="Italic">Leporinus obtusidens</Emphasis> from Mogi-Guaçu River,Brazil

Henneguya azevedoi n. sp. is described from the piava (Leporinus obtusidens). Between 2005 and 2007, 60 fish were collected from the Mogi-Guaçu River near Cachoeira de Emas Falls located in the municipality of Pirassununga, state of São Paulo, Brazil. A total of 70% had plasmodia of the parasite. The plasmodia were white, spherical, and measured 40–200 μm in diameter. Histopathological analysis revealed that the development of the parasite was intralamellar and caused stretching of the epithelium, with accentuated deformation, as well as compression of the capillary and adjacent tissues. Ultrastructural analysis revealed that the wall of the plasmodium was a single membrane in direct contact with the host cells and contained pinocytic canals that extended into the plasmodium. The development of the parasite was asynchronous, with the earliest stages at the periphery and mature spores in the central region. Mature spores were elongated in the frontal view [mean?±?standard deviation (range)]: 45.2?±?0.6 (45.0–47.0)?μm in total length, 10.0?±?0.07 (9.9–10.2)?μm in body length, 35.6?±?0.9 (34.9–36.5)?μm in caudal process length, and 4.4?±?0.4 (4.0–5.0)?μm in body width. The polar capsules were elongated and equal in size: 3.8?±?0.3 (3.5–4.0)?μm in length and 1.0 μm in width. The polar filaments were coiled in six to seven turns and perpendicular to the axis of the capsule. Scanning electron microscopy revealed smooth valves and a conspicuous rim around the spore body. This is the first time that a myxosporean has been reported in L. obtusidens.     

Light and electron microscopic studies on Kudoa pagrusi sp. n. (Myxosporea: Multivalvulida) infecting the heart of sea bream Pagrus pagrus (L.) from the Red Sea

A new multivalvulid species, Kudoa pagrusi sp. n., was described from the sea bream Pagrus pagrus. The cysts were oval to ellipsoidal and restricted to the cardiac muscles. The mean spore measurements were 7.0 μm in length and 6.4 μm in width as well as in thickness, while the mean polar capsule measurements were 3.7 μm in length and 1.5 μm in width. The ultrastructural features of the present species proved that the spore have four polar capsules with four shell valves that are the main criteria for genus Kudoa.     

Thelohanellus niloticus sp. nov. (Myxozoa: Myxosporea), a parasite of the Nile carp Labeo niloticus from the River Nile, Egypt

In the present study, the morphology and morphometric characterization of Thelohanellus niloticus sp. nov., a new myxozoan belonging to genus Thelohanellus Kudo, 1933 (Myxosporea, Bivalvulida) infecting the gills of Labeo niloticus (Osteichthyes, Cyprinidae), were described for the first time from the River Nile at El-Minia Governorate, Egypt. Forty-one out of 78 (52.6 %) of the examined fish were infected. The infection was observed as irregular, milky whitish, cyst-like plasmodia (up to 0.8 mm in diameter) attached to the gill filaments of the host fish. These plasmodia contained tear-shaped myxospores with slightly tapering anterior and rounded posterior ends. Each spore has a single pyriform polar capsule. Spores measured about 23.3?±?0.3 (20.4–27.1) μm long and 13.4?±?0.4 (11.5–14.2) μm wide. The polar capsule was 11.7?±?0.3 (9.2–12.5) μm long and 4.7?±?0.3 (3.5–6.2) μm wide, containing a polar filament coiled perpendicular to the longitudinal axis of the spore body making eight turns. Occasionally, an oblong, irregular-shaped mass of protoplasm with a slightly oval nucleus (1.4 μm in diameter) and a small iodinophilous vacuole measured 0.85?±?0.2 μm (0.73–1.2 μm) were observed in the spore. Due to the lack of the second polar capsule characterizing Myxobolus sp., the present parasite is placed within the genus Thelohanellus. Based on morphological differences (compared with other members of Thelohanellus Kudo, 1933) and the host specificity, this species is described as a new one of the genus Thelohanellus recorded for the first time in Egypt.     

<Emphasis Type="Italic">Kudoa unicapsula</Emphasis> n. sp. (Myxosporea: Kudoidae) a parasite of the Mediterranean mullets <Emphasis Type="Italic">Liza ramada</Emphasis> and <Emphasis Type="Italic">L. aurata</Emphasis> (Teleostei: Mugilidae)

A new multivalvulid myxozoan parasite, Kudoa unicapsula n. sp., is described from the intestinal mesentery, intestine and pyloric caeca of the thin-lipped grey mullet Liza ramada (Risso 1826) and the golden grey mullet L. aurata (Risso, 1810) from the Mediterranean coastal waters of Spain. It is characterized by the presence of elongated, rice corn-like white cysts of 0.47–0.56 × 0.18–0.38 mm, filled with tetracapsulate, slightly asymmetric spores, rectangular in apical view and tear-shaped in lateral view with four polar capsules of considerably different size and slightly unequal spore valves with rounded edges, overlapping each other on the apex of the spore. One large polar capsule includes a polar filament coiled in two to three turns, and the other three polar capsules, which are very small, posses only a rudimental filament. Both light and electron microscopy data showed that this species differs from all previously described Kudoa spp. with unequal polar capsules. The molecular analysis based on 18S and 28S ribosomal deoxyribonucleic acid DNA sequence data of K. unicapsula n. sp. indicates a close relationship and thus phylogenetic clustering together with K. trifolia, a myxozoan from the same host and the same geographical location.     

First report of Kudoa species (Myxozoa: Kudoidae) infecting the spotted coral grouper Plectropomus maculates from the Red Sea. A light and ultrastructural study

In the present study, out of 200, 120 (60?%) Plectropomus maculates fish were found to be naturally infected with Kudoa sp. The infection was intensive and appeared as clusters of ovoid to ellipsoidal plasmodia being restricted to the cardiac muscles. More than 100 plasmodia were counted per infected heart and measured 1.53?±?0.2 (1.2-2.5)?×?0.65?±?0.2 (0.63-0.80)?mm. On the basis of spore morphology, the parasite was identified as Kudoa sp. The spore measures 4.8?±?0.3 (4.7-6.8)?×?4.0?±?0.3 (4.6-6.5)?μm. The four polar capsules were pyrifom in shape measuring 1.4?±?0.2 (1.3-3.5)?×?1.2?±?0.2 (1.1-2.2)?μm. Transmission electron microscopy showed that the plasmodia were bordered by a single membrane which invaginates into pinocytotic canals. Adjacent to the plasmodial wall, the generative cells and the early pansporoblasts were located peripherally. The developmental stages characterizing sporogenesis, capsulogenisis, and valvogenesis of the present parasites were ultrastructurally studied.     

Characterization of the ribosomal RNA gene of Kudoa neothunni (Myxosporea: Multivalvulida) in tunas (Thunnus spp.) and Kudoa scomberi n. sp. in a chub mackerel (Scomber japonicus)

Kudoa neothunni is the first described Kudoa species having six shell valves and polar capsules, previously assigned to the genus Hexacapsula Arai and Matsumoto, 1953. Since its genetic analyses remain to be conducted, the present study characterizes the ribosomal RNA gene (rDNA) using two isolates from a yellowfin tuna (Thunnus albacares) with post-harvest myoliquefaction and a northern bluefin tuna (Thunnus thynnus) without tissue degradation. Spores of the two isolates localized in the myofiber of trunk muscles, forming pseudocysts, and showed typical morphology of K. neothunni with six equal-sized shell valves radially arranged in apical view: spores (n?=?15) measuring 9.5–11.4 μm in width, 7.3–8.6 μm in suture width, 8.9–10.9 μm in thickness, and 7.3–7.7 μm in length; and polar capsules measuring 3.6–4.1 μm by 1.8–2.3 μm. In lateral view, the spores were pyramidal in shape without apical protrusions. Their 18S and 5.8S rDNA sequences were essentially identical, but variations in the ITS1 (62.4 % similarity across 757-bp length), ITS2 (66.9 % similarity across 599-bp length), and 28S (99.0 % similarity across 2,245-bp length) rDNA regions existed between the two isolates. On phylogenetic trees based on the 18S or 28S rDNA sequence, K. neothunni formed a clade with Kudoa spp. with more than four shell valves and polar capsules, particularly K. grammatorcyni and K. scomberomori. Semiquadrate spores of a kudoid species with four shell valves and polar capsules were detected from minute cysts (0.30–0.75 mm by 0.20–0.40 mm) embedded in the trunk muscle of a chub mackerel (Scomber japonicus) fished in the Sea of Japan. Morphologically, it resembled K. caudata described from a chub mackerel fished in the southeastern Pacific Ocean off Peru; however, it lacked filamentous projections on the shell valves of spores. Additionally, it morphologically resembled K. thunni described from a yellowfin tuna also fished in the Pacific Ocean; spores (n?=?30) measuring 8.2–10.5 μm in width, 7.0–8.8 μm in thickness, and 6.1–6.8 μm in length; and polar capsule measuring 2.5–3.4 μm by 1.3–2.0 μm. The similarities of the 18S and 28S rDNA sequences between these two species were 98.5 % and 96.3 %, respectively. Simultaneously, the dimensions of cysts in the trunk muscle formed by K. thunni are clearly larger than those of the present species from a chub mackerel: 1.3–2.0 mm by 1.1–1.4 mm (n?=?14) vs. 0.30–0.75 mm by 0.20–0.40 mm (n?=?7), respectively. Thus, Kudoa scomberi n. sp. is proposed for this multivalvulid species found in the chub mackerel.     

Structural and molecular characterization of Kudoa quraishii n. sp. from the trunk muscle of the Indian mackerel Rastrelliger kanagurta (Perciforme,Scombridae) in Saudi Arabia coasts

A new Myxozoa, Kudoa quraishii n. sp., is reported in the striated muscle of the Indian mackerel Rastrelliger kanagurta from the Red Sea and the Arabian Gulf in Saudi Arabia. Mean prevalence of infection is about 20 % and varies between localities. The parasite develops whitish and oval or rounded pseudocysts of 0.2–3 mm in the striated muscles of the body. Pseudocysts are filled with mature spores. Myxospores are quadrate in shape in apical view with rounded edges and ovoid in side view. Each spore is formed by four equal shell valves and four symmetrical polar capsules. Polar capsules are pyriform in apical view and drop-like in side view. Myxospore measurements in micrometers are 6.14 (5.9–6.34) in width, 5.48 (5.3–5.71) in thickness, and 4.27 (4.1–4.42) in length. Polar capsule measurements in apical view in micrometers are 2.08 (1.88–2.28) and 1.31 (1.10–1.52) length by width. Molecular analysis based on SSU rDNA gene shows closest association with K. amamiensis and K. kenti with respectively 98 and 97.2 % of similarities.     

Kudoa iwatai and two novel Kudoa spp., K. trachuri n. sp. and K. thunni n. sp. (Myxosporea: Multivalvulida), from daily consumed marine fish in western Japan

Infection of marine fish by certain myxosporean species of the genus Kudoa results in unsightly cyst formation in the trunk muscle or post-mortem myoliquefaction, causing a great economic loss to aquaculture industries, capture fisheries, and fish dealers. In addition, consumers encountering unsightly Kudoa cysts in fish fillets believe them to be unknown foreign materials acquired during processing. To identify prevalent Kudoa spp. encountered in daily life by the Japanese population, fresh fish slices (sashimi) or fish fillets with whitish spots were collected during a 7-month period (May to December 2008) at local markets in the city of Yamaguchi, western Japan. Kudoa cysts were found in three Japanese seaperches (Lateolabrax japonicus), two black sea bream (Acanthopagrus schlegelii), two Japanese jack mackerel (Trachurus japonicus), and one albacore (Thunnus alalunga). Kudoa iwatai was identified in all the examined Japanese seaperch and black sea bream from Japan’s Inland Sea, as assessed by morphology and genetic analysis of the 18S and 28S ribosomal RNA gene (rDNA). Kudoa trachuri n. sp. from two Japanese jack mackerel fished in the Japanese Sea off Nagasaki and Kudoa thunni n. sp. from one albacore fished in the Pacific Ocean had a spore, which was semiquadrate in shape in apical views and ovoid in lateral views, with four equal shell valves and drop-like polar capsules. Scanning electron microscopy revealed that these three Kudoa species had different types of small projections at the apex of each valve. The 18S and 28S rDNA sequences of K. trachuri n. sp. and K. thunni n. sp. were found to be closely related to those of Kudoa crumena; however, these sequences were distinct in each of the species, which additionally exhibited different morphological features.     

Ortholinea auratae n. sp. (Myxozoa,Ortholineidae) infecting the urinary bladder of the gilthead seabream Sparus aurata (Teleostei,Sparidae), in a Portuguese fish farm

A new myxosporean species, Ortholinea auratae n. sp., is described from the gilthead seabream, Sparus aurata Linnaeus, 1758 (Teleostei, Sparidae) from a fish farm in Algarve, Portugal. Plasmodia and spores were found in the urinary bladder and, less frequently, in the posterior kidney. Plasmodia were polymorphic, presenting an irregular cellular membrane due to the presence of several peripheral projections, which in turn were covered by a glycocalyx-like sheet. Mature spores were subspherical in valvular view and ellipsoidal in sutural view, measuring 9.0?±?0.3 (8.2–10.1) μm in length, 8.3?±?0.4 (7.5–9.1) μm in width, and 7.2?±?0.5 (6.3–8.4) μm in thickness. The two valves comprising the spores displayed an intricate pattern of surface ridges and were also enveloped by a glycocalyx-like sheet. Two subspherical polar capsules, 3.2?±?0.1 (2.9–3.6) μm long and 2.7?±?0.1 (2.4–2.9) μm wide, were located at the anterior pole and displayed divergent orientation. The polar filament coiled in three to four turns. The comprehensive analysis of the parasite’s ultrastructural observations and molecular data for the small subunit (SSU) ribosomal DNA (rDNA) gene identify O. auratae n. sp. as a new species, clustering together with other myxosporeans infecting the excretory system to form a subclade of the main freshwater clade.     

Three Unicapsula species (Myxosporea: Trilosporidae) of Asian marine fishes,including the description of Unicapsula setoensis n. sp. in the yellowfin goby (Acanthogobius flavimanus) from the Inland Sea of Japan

The myxosporean genus Unicapsula (Multivalvulida: Trilosporidae) is defined as having a spore with three unequal shell valves and polar capsules, of which one is prominent and the two other polar capsules are rudimentary. Genetic characterization of members of the genus, currently 11 nominal species, is, at present, unsatisfactory yet when comparing to the closely related genus Kudoa (Multivalvulida: Kudoidae). In the present study, we characterized long ribosomal RNA gene (rDNA) sequences of three Unicapsula spp., namely Unicapsula pyramidata, Unicapsula seriolae, and a novel myxosporean species, Unicapsula setoensis n. sp., from Asian fishes. Elongated plasmodia of U. pyramidata were found in the trunk muscle of Japanese threadfin breams, Nemipterus japonicus, fished off northern Vietnam in the South China Sea. Semitriangular spores, 5.5–6.4 μm in length and 5.6–9.6 μm in width, consisted of three shell valves with two caudal appendages, 7.2–7.4 μm in length. One prominent polar capsule, 2.0–2.4 μm in diameter, was located in the apical shell valve and two rudimentary polar capsules, 0.4–0.5 μm in diameter, in each caudal shell valve. Elongated plasmodia of U. seriolae were found in the trunk muscle of a greater yellowtail, Seriola dumerili, aquacultured in Japan. Semispherical spores, 5.9–7.4 μm in length and 6.3–7.4 μm in width, also consisted of three shell valves and one prominent polar capsule, 3.4–3.8 μm in diameter, with two rudimentary polar capsules, 0.7–1.0 μm in diameter. Plasmodia of U. setoensis n. sp. were found in the trunk muscle of yellowfin gobies, Acanthogobius flavimanus, fished off Hofu, Yamaguchi Prefecture, in the Inland Sea of Japan. Semispherical spores, 5.6–6.9 μm in diameter, displayed three shell valves and one prominent and two rudimentary polar capsules. The former functional polar capsule was 1.9–2.5 μm in diameter and extruded a 9.4–13.8-μm-long polar filament. Nearly the whole length of the 18S rDNA and more than 2,200 bp of the 28S rDNA of the three Unicapsula spp. were sequenced along with nucleotide sequences of the 5.8S rDNA and internal transcribed spacer-1 and spacer-2 of U. pyramidata and U. setoensis n. sp. Molecular genetic analyses supported the morphological species differentiation of U. pyramidata and U. seriolae, and the distinctness of U. setoensis n. sp. from hitherto known species.     

The morphological and molecular characterization of Myxobolus khaliji n. sp. (Myxozoa: Myxosporea) from the double bar seabream Acanthopagrus bifasciatus (Forsskål, 1775) in the Arabian Gulf,Saudi Arabia

Myxobolus khaliji n. sp., a new myxosporean, is described from the intestinal wall of the double bar seabream Acanthopagrus bifasciatus, collected from the Arabian Gulf off the coast of Saudi Arabia. It is characterized by the presence of ellipsoidal or round plasmodia of 2–4 mm in diameter. Mature spores were subspherical to elliptical in the frontal view, with a slightly pointed anterior end and a bluntly rounded posterior end, and measured 8.1?±?0.4 (7.2–9.5) μm long, 6.3?±?0.6 (5.1–7.4) μm wide, and 9.2?±?0.7 (8.3–10.2) thick. Spore valves are relatively thin, sometimes with a prominent thick caudal appendage. Two equal elliptical polar capsules were situated in the plane of the suture line at the anterior end of the spores and occupied above half of the spore length. Polar capsules measured 5.5?±?0.7 (4.1–6.1) μm long and 3.2?±?0.2 (2.1–4.2) μm wide. Polar filaments, wound in three to four coils, were situated perpendicularly to the longitudinal axis of the polar capsules. Combining the morphological characteristics, host specificity and geographical distribution, tissue tropism, and the molecular analysis of the partial sequence of the SSU ribosomal DNA gene, it was concluded that M. khaliji n. sp. was distinct from all previously described Myxobolus species. Phylogenetic analysis placed the present Myxobolus species in a marine Henneguya clade, which is a sister group of marine Myxobolus species. This is the first Myxobolus species with Henneguya-like spores from the marine environment to be found in the Saudi Arabian coasts of the Arabian Gulf.     

Prevalence,morphology, and molecular analysis of Serrasentis sagittifer (Acanthocephala: Palaeacanthocephala: Rhadinorhynchidae), a parasite of the gilthead Sea bream Sparus aurata (Sparidae)

Seventy specimens of the gilthead sea bream Sparus aurata of the Red Sea were collected during the period from March to November 2013; they were dissected and examined for parasitic acanthocephalans. Only 40 (57.14 %) specimens were found to be naturally infected with Serrasentis sagittifer belonging to family Rhadinorhynchidae. The infection was recorded in the intestine, pyloric ceca, and the external surfaces of some internal organs of the infected fish. Seasonally, the prevalence of infection was increased to 77.14 % during summer season and decreased to 37.14 % during winter. Light and scanning electron microscopic investigation revealed that the adult worm was elongated (with broad anterior and narrow posterior ends) and measured 6.9–8.6 (7.6?±?0.2)?×?0.57–0.73 (0.63?±?0.02) mm for male and 10.2–12.1 (11.5?±?0.2)?×?0.71–0.82 (0.76?±?0.02) mm for female. Proboscis was long and cylindrical with a length of 0.97–1.6 mm (1.2?±?0.2) for male and 1.12–1.17 mm (1.14?±?0.02) for female. It was covered with numerous uniform spines arranged longitudinally as 9–11 rows each equipped by 15–18 spines. Spines were triangular, arrow-shaped, strong, and covered with cuticular theca; they decreased in size from the apex to the base of the proboscis. The proboscis is followed by a short spineless neck region followed by the body proper which is supported by multiple combs of spines (16–20) on its ventral surface. Molecular analysis of 18S rDNA sequence for the parasite demonstrated a close identity (>83 %) between the present acanthocephalan and other previously described species within class Palaeacanthocephala with 98 % identity with the previously recorded S. sagittifer (acc. no. JX014227) which is supported by the morphological data and the presence of trunk spines arranged within rows (comb-like) and the presence of four cement glands in the males. So, according to the records of morphological and molecular analyses, the present parasite is classified as S. sagittifer belonging to class Palaeacanthocephala and family Rhadinorhynchidae with a new host record from the gilthead sea bream S. aurata of the Red Sea.     

Morphological and molecular characterization of Lecithochirium grandiporum (Digenea: Hemiuridae) infecting the European eel Anguilla anguilla as a new host record in Egypt

In the present study, the morphological and molecular characterization of Lecithochirium grandiporum, a digenetic trematode infecting the European eel Anguilla anguilla (Family (F): Anguillidae), were described for the first time from Burullus Lake, Kafr El-Sheikh Governorate, Egypt. Twenty-five out of 60 specimens (infection rate of 41.66 %) were found to be naturally infected. Infection was recorded as small worms attached to the inner wall of the intestine of host fish. Adult worms measured 1.59?±?0.20 (1.3–1.85)?mm long and 0.3?±?0.02 (0.29–0.48)?mm wide for everted specimens with a smaller oral sucker measuring 0.15?±?0.02 (0.13–0.18)?mm, and a larger ventral sucker which was 0.16?±?0.02 (0.14–0.25)?mm. Our results recorded morphological differences as smaller dimensions of different body parts and the smaller oral/ventral sucker ratio between Lecithochirium fusiforme and L. grandiporum. Also, the phylogenetic position of the worm was determined by molecular characterization of their 18 SSU rDNA. Results were compared with those of previously recorded species on the Gene Bank. It was found that the present species coincide with those belonging to genus Lecithochirium. Comparison of the nucleotide sequences and divergence showed that the SSU rDNA gene of this Lecithochirium species revealed 92 % sequence identity with L. fusiforme (accession no. DQ413192) differing in 26 nucleotides with lower divergence value. According to these results, this study indicated that the present species is recorded as L. grandiporum with accession no. KC166146 as a parasite with new host and locality records in Egypt.     

Study of Myxosporea (Myxozoa), infecting worldwide mullets with description of a new species

Existing data on Myxozoa parasites infecting mullets were reviewed. The validity of nine species names was updated. Sixteen species were registered during analysis of original material collected in the Mediterranean, Black, Azov, and Japan Seas in 2004–2005. A new bivalvulid myxozoan parasite, Myxobolus adeli n. sp., was described from the inner organs of the golden grey mullet Liza aurata (Risso, 1810) collected in the Mediterranean (Ebro Delta, Spain), Black Sea (Kerch Strait, Ukraine), and Azov Sea (Genichesk, Ukraine) coastal waters. It is characterized by the presence of elongated, spindle-like cysts 0.5–1.3 mm in size, filled with wide transverse-oval spores about 6.2?×?7.2?×?4.6 μm in size, with two equal polar capsules measuring about 3.0?×?1.8 μm and short polar filament, turned into four coils. The obtained data show that this species differs from all previously described Myxobolus spp. with equal polar capsules. Comparative study of Myxobolus spp. recorded in worldwide mullets indicates a close relationship with M. adeli n. sp. and Myxobolus improvisus Isjumova, 1964 registered in mullets. Probably, the last species includes representatives of some different species, infecting freshwater and marine hosts.     

Two novel myxosporean species (Myxosporea: Bivalvulida), Myxobolus marumotoi n. sp. and Cardimyxobolus japonensis n. sp., from the dark sleeper,Odontobutis obscura,in Japan

Two new myxosporean species, Myxobolus marumotoi n. sp. and Cardimyxobolus japonensis n. sp. (Myxozoa: Myxosporea: Bivalvulida), are described from the dark sleeper, Odontobutis obscura, in Japan, based on their morphological and molecular characterizations. Plasmodia of M. marumotoi n. sp. (Myxobolidae) grew in the myofiber of trunk muscles, forming pseudocysts. The rounded spore was relatively large, measuring 13.3–15.0 μm (average 13.8) in length, 14.2–15.0 μm (14.6) in width, and 10.0–11.7 μm (10.8) in thickness, with two subspherical polar capsules of 7.9–9.6 μm (8.4) in length by 5.4–6.3 μm (5.9) in width (n?=?15). The polar capsules were directed toward the apex of the spore, packing five to six spirals of the polar filament. Plasmodia of C. japonensis n. sp. (Ortholineidae) were surrounded by thin fibrous tissue, forming cysts in the lamina propria of the alimentary tract. The spore was ovoid, wider than long, in valvular view and spindle-shaped in sutural view. It measured 8.8–10.4 μm (9.4) in length, 11.3–12.5 μm (11.9) in width, and 5.2–6.7 μm (5.8) in thickness, with two ovoid polar capsules of 4.2–5.0 μm (4.7) in length by 2.9–3.8 μm (3.3) in width (n?=?15). The shell valves of spores often showed a flattened anterior border and semicircular posterior border, and the two polar capsules were directed toward opposite lateral sides. In addition, the sporoplasm contained an iodinophilous vacuole. Almost complete small-subunit (SSU) rDNA sequences, except for primer flanking regions, were obtained for both species; 1,996 bp long for the former and 1,588 bp long for the latter. On phylogenetic trees based on the SSU rDNA sequences of representative species of Bivalvulida, M. marumotoi n. sp. and C. japonensis n. sp. formed a distinct branch in the Henneguya/Myxobolus clade or near but outside this clade, respectively. This study is the first report of the genetic characterization for the genus Cardimyxobolus.