Facieplatycauda pratti gen. n., sp. n. and Two New Species of Myxobolus (Myxosporida)*

Synopsis. Facieplatycauda pratti gen. n., sp. n. and Myxobolus kozloffi sp. n., from the Klamath Lake sucker, Catostomus luxatus (Cope), are described. The new genus is placed in the family Myxobolidae between Henneguya and Myxobolus. The spore valves beyond the sporoplasmic space are broad and long but not attenuated as an inverted triangle as in certain species of Myxobolus with tails, or of Henneguya with sometimes bifurcated tails. An organism resembling Myxobolus insidiosus (Wyatt & Pratt) was found in the muscle of the body of Salmo clarki (Richardson). Differences in spore structure and site of infection suggest this is a subspecies of the previous form which should be designated Myxobolus insidiosus clarki. A previously unreported species of Myxobolus from Cottus aleuticus (Gilbert) is also described.     

Henneguya tunisiensis n. sp. (Myxosporea: Bivalvulida), a new gill parasite of Symphodus tinca (L.) (Teleostei: Labridae) off Tunisia

Henneguya tunisiensis n. sp., a new myxosporean, is described from the gill-arches of the East Atlantic peacock wrasse Symphodus tinca (L.) collected from off the Kerkennah Islands, Tunisia. It is characterised by the presence of elongate white plasmodia of 1–1.5 × 1.5–2 mm in size. The mature spores are rounded in frontal view and have two identical polar capsules and two caudal appendages which taper considerably at the end. Both light and electron microscopical data show that this species differs in several morphological features from all previously described Henneguya spp. A molecular analysis, based on 18S rDNA sequence data, indicates that H. tunisiensis n. sp. is readily distinguishable from other myxozoan DNA sequences in GenBank. Phylogenetically, the new species is placed in the marine Henneguya clade, which is a sister group of marine Myxobolus spp. from perciform fishes in Tunisian waters.     

Two new species of Myxobolus (Myxozoa: Myxobolidae) infecting the gill and scales of the smallmouth bass,Micropterus dolomieu (Centrarchiformes: Centrarchidae) in the French Broad River Basin,North Carolina

Two new species of Myxobolus Bütschli, 1882 (Bivalvulida: Myxobolidae) are described from the gill and scales of smallmouth bass (Micropterus dolomieu Lacepède, 1802 [Centrarchiformes: Centrarchidae]) from the Watauga River, French Broad River Basin, North Carolina, United States. Myxobolus intralamina n. sp. infects the lumen of the lamellar arterioles and Myxobolus infrabractea n. sp. infects the inner surface of the scale. They differ from all congeners by a combination of myxospore dimensions, polar tubule coil count, and the presence or absence of an iodinophilic vacuole in the sporoplasm and an intercapsular process. A phylogenetic analysis of the small subunit ribosomal DNA (SSU rDNA) recovered M. intralamina n. sp. sister to Myxobolus lepomis and Myxobolus branchiarum and M. infrabractea n. sp. sister to Myxobolus micropterii in a clade composed of five Myxobolus spp. infecting centrarchids and Henneguya spp. (Myxobolidae) infecting percids. Histological sections of infected gill revealed intra-lamellar plasmodia of M. intralamina n. sp. within the lumen of the lamellar arterioles and plasmodia of M. infrabractea n. sp. developing beneath the scales. These new species comprise the first species of Myxobolus reported from a black bass (Micropterus Lacepède, 1802) in the Southeast United States.     

<Emphasis Type="Italic">Myxobolus imparfinis</Emphasis> n. sp. (Myxozoa: Myxosporea), a new gill parasite of <Emphasis Type="Italic">Imparfinis mirini</Emphasis> 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.     

Description of a new species of myxobolid parasite,Henneguya pindaibensis n. sp. (Cnidaria: Myxosporea), infecting the gills of Boulengerella cuvieri (Spix and Agassiz, 1829) from Brazil

Myxozoans are microscopic cnidarians that mainly parasitize fishes. The present study aimed to describe a new myxozoan parasite from the gills of Boulengerella cuvieri (Spix and Agassiz, 1829) by morphological and molecular analysis. The fish was collected in 2019 at the Pindaíba River, municipality of Cocalinho, Mato Grosso State, Brazil. Whitish and circular plasmodia were found in the primary gill filaments, occupying an intralamellar position, with an average of 0.5 mm in diameter. Henneguya Thélohan, 1892 myxospores found inside the plasmodia were elongated and ellipsoidal, consisting of two long and elliptical shell valves with two long, tapering caudal appendages. Morphometric measurements revealed a total spore length of 36.1 ± 2.0 μm; spore body length of 12.8 ± 0.5 μm; spore width of 4.9 ± 0.3 μm; tail length of 23.3 ± 1.6 μm; capsule length of 7.2 ± 0.4 μm; capsule width of 1.5 ± 0.2 μm; and 10 coils in the polar filament. Phylogenetic analysis showed that the isolates from this study were grouped into the main-clade of freshwater fishes, within a group of species parasitizing fishes from Brazil. Intergenotypic difference ranged from 23%–25.9% compared with other Brazilian myxozoan isolates. Using molecular and morphological characterization, this parasite was identified as a new species of the genus Henneguya.     

A skin disease of the eels caused by Myxobolus kotlami n. sp.

In elvers (Anguilla anguilla) imported yearly to a fish farm in Hungary the regular occurrence of a Myxobolus infection was recorded. The parasite produces oval or spherical plasmodia of 0.1–0.2·0.07–0.12mm in the subcutaneous and intermuscular connective tissue of the head. In each piasmodium about 200 to 400 spores develop which differ morphologically from the spores of all Myxobolus species known from the eel and other fishes. Based upon the characteristic location of plasmodia and spore morphology, this parasite is described as a new species, Myxobolus kotlani.     

Morphological,ultrastructural, and molecular analysis of a new species of Myxobolus (Cnidaria,Myxosporea) parasitizing Apareiodon piracicabae (Characiformes,Parodontidae) from Brazil

About forty-two species of Myxobolus have been previously described to parasitize characiform fishes in South America. Here, we described a new myxozoan species, Myxobolus parodontidis n. sp., in the gills of Apareiodon piracicabae (Characiformes, Parodontidae) from the streams of the Middle Paranapanema River basin, Brazil. The proposed new species is supported by a combination of morphological, ultrastructural, and molecular characterization (small subunit ribosomal DNA). Thirteen specimens of A. piracicabae were analyzed and 30.8% was infected by Myxobolus parodontidis n. sp. The myxospores was classified as intralamellar asymmetric type. A few aberrant myxospores with three polar capsules were observed: the spore length and width were the same of normal myxospores, but the polar capsules had smaller sizes. Ultrastructural analysis showed that the plasmodial membrane of Myxobolus parodontidis n. sp. was in direct contact with the host tissue and a connective capsule surrounding the plasmodium was not observed. The phylogenetic analysis showed that the main influence in the clustering of species of myxobolids seems to be related to the phylogenetic relationships established among fish hosts, mainly at the level of family and order. This is the first record of a myxozoan species parasitizing parodontid fish, contributing to the knowledge of the biodiversity of myxozoans from Brazil.     

Myxobolus albi n. sp. (Myxozoa) from the Gills of the Common Goby Pomatoschistus microps Krøyer (Teleostei: Gobiidae)

ABSTRACT. A recent investigation into the myxozoan fauna of common gobies, Pomatoschistus microps , from the Forth Estuary in Scotland, revealed numerous myxosporean cysts within the gill cartilage. They were composed of polysporous plasmodia containing myxobolid spores that were morphologically different from the other known species of Myxobolus and from the myxosporeans previously recorded from this host (i.e. the ceratomyxid Ellipsomyxa gobii , infecting the gall bladder, and the kudoid Kudoa camarguensis , infecting the muscle tissues). Spores were ovoid, 9.4 × 9.1 μm with a thickness of 6.6 μm, with two pyriform polar capsules, the polar filaments of which had four to five turns. Molecular analysis of the parasite's small subunit rDNA region, based upon a contiguous sequence of 1,558 base pairs, discriminated it from other myxosporean species that have been characterized so far. A comparison of the spore morphology and the molecular sequences determined for this new isolate with other myxozoans described to date, confirmed its identity as a previously unknown myxobolid supporting the proposal that this isolate be elevated to the species level as a new species within the genus Myxobolus . A phylogenetic analysis places this new myxobolid, Myxobolus albi n. sp., in a basal position of a clade containing the majority of Henneguya spp. sequenced to date and various Myxobolus spp.     

Myxobolus shuifuensis sp. n. (Myxozoa: Myxobolidae) infecting the exotic mrigal Cirrhinus mrigala feral in China

Myxobolus species represents a group of cosmopolitan metazoan parasites commonly harbored in the farmed and wild fish populations. Here, a species of Myxobolus is found in the kidney of an exotic mrigal Cirrhinus mrigala feral in the Yangtze River and utilized for an integrative characterization. Ellipsoidal myxospores are measured at 15.68 ± 0.8 (13.93–17.11) × 11.42 ± 0.54 (10.34–12.3) × 7.94 ± 0.35 (7.58–8.5) μm in dimension. The polar capsules are pyriform, and unequal in size. The morphological and morphometric characteristics of the present isolates are distinct from those of other congeners. Molecularly, the pairwise comparison based on the SSU rDNA sequence indicates that the present amplicon does not match any sequences available in the GenBank database and shares the highest similarity of 92.12% to Myxobolus pavlovskii (MG520369). Accordingly, we propose a name Myxobolus shuifuensis sp. n. for the present isolates. Phylogenetical trees indicate an apparent host-associated phylogenetic pattern. M. shuifuensis sp. n. groups loosely with other Myxobolus species isolated from Cirrhinus fish. Insead, it forms a sister clade to some myxosporeans belonging to the Thelohanellus genus. This result underpins the species identification and provides evidence for challenging the taxonomic separation among both morphologically comparable genera.     

Morphology evolution and molecular phylogeny of Pestalotiopsis (Coelomycetes) based on ITS2 secondary structure

The internal transcribed spacer 2 (ITS2) located between the 5.8S and 28S genes of the nuclear ribosomal gene cistron is conserved at the level of secondary structure rather than primary sequence. Within the fungal genus Pestalotiopsis, there were two types of ITS2 sequence patterns, and hence secondary structures, which were supported by high bootstrap values in phylogenies based on the ProfDist distance and Profile neighbor-joining algorithms. Pestalotiopsis consists of two groups that differ in color intensity of the spore as measured by optical density (OD) in three median cells of conidia comprised of five cells with one basal and two to four apical appendages. OD was quantified using a novel method with the publicly available software, Image J. OD values of species within one clade were high (dark OD >0.6), while OD values of species in the other clade were low (pale OD <0.6). However, knobbed-tipped appendages, which have been used to classify species of Pestalotiopsis, were observed in both clades. In the dark clade, knobbed-tipped appendage strains aggregated in one subclade, but in the pale group, these strains did not aggregate.     

Testicular myxosporidiasis in the flat-backed toad, Bufo maculatus (Amphibia: Bufonidae), from Cameroon, Africa.

Macroscopic cysts measuring less than or equal to 860 x 500 microns were found in the testes of a flat-backed toad, Bufo maculatus, collected in Cameroon, West Africa. On histologic examination, the cysts contained numerous spores of a Myxobolus sp. (Myxozoa: Myxobolidae). Spores in fixed tissues measured 9.2 microns long, 8.9 microns wide, and 4.0 microns thick; the range of values for length, width, and thickness were 8.8 to 9.6 microns, 8.6 to 9.4 microns, 3.6 to 4.4 microns, respectively (n = 20). The shape index (length/width) was 1.03, and ranged from 1.00 to 1.09. Pathology was limited to a slight constriction of adjacent seminiferous tubules by the cysts. No host inflammatory response was noted. This myxozoan is distinct from all other members of the genus infecting anurans and is assigned the name Myxobolus bufonis sp. n.     

Henneguya polarislonga n. sp. (Cnidaria: Myxosporea) parasitizing Astyanax lacustris (Lütken, 1875) with an insight on its life cycle

Henneguya polarislonga n. sp. is described from the gills of Astyanax lacustris (Lütken, 1875) (Characiformes, Characidae) from streams of the Middle Paranapanema River, Upper Paraná River basin, in the São Paulo State, Brazil. The proposed new species is supported by a combination of morphological and molecular characterization (partial fragment of the SSU rDNA). Thirty specimens of A. lacustris were analyzed and myxospores were found in the gill lamellae of one specimen (Prevalence = 3.3%). Henneguya polarislonga n. sp. was morphometrically and genetically distinct from other Henneguya spp. previously described in Astyanax spp., mainly differing in the total length and caudal appendages length of the mature myxospores. Comparative analysis of the SSU rDNA sequences revealed that Seisactinomyxon-type actinospores previously reported parasitizing oligochaetes are developmental stages of the life cycle of Henneguya polarislonga n. sp. (similarity of 99.9%). This is the first time that an actinospore and a myxospore are correlated through molecular analysis in Brazil, contributing to the knowledge of the myxozoan ecology and biodiversity.     

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

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

Synopsis of the species of the genus Henneguya Thélohan, 1892 (Myxozoa: Myxosporea: Myxobolidae

This synopsis of the species of the genus Henneguya (Myxozoa, Myxosporea, Myxobolidae) includes a total of 146 species. Morphometric and morphological (when available) features are indicated for each species. Data related to the hosts are also provided.     

Preliminary phylogenetic analysis of the fern genus Lomariopsis (Lomariopsidaceae)

A preliminary phylogenetic analysis is presented forLomariopsis based on sequence data from the chloroplast intergenic spacertrnL-trnF. The analysis includes 27 (60%) of the approximately 45 species in the genus. A strict consensus of six most parsimonious trees supports two main clades—theSorbifolia-group and theJapurensis-group—previously proposed based on heteroblastic leaf development. TheSorbifolia-group is entirely neotropical and includes all the Antillean species. The species in this clade had either smooth or crested spores, but the tree was ambiguous whether these spore types define two separate clades. TheJapurensis-group consists of two clades, one primarily neotropical and the other entirely paleotropical. Within the neotropical clade nests a clade of two African species, which have long-spiny spores typical of the neotropical clade and unlike those found in the African-Madagascan clade. The occurrence of these two species in Africa is best explained by longdistance spore dispersal of their ancestral species from the neotropics to Africa. Within the paleotropical clade of theJapurensis-group, a clade of three African species is nested among seven species from Madagascar (all the species from that island). Within the genus as a whole, a derived character—the abortion of the rachis apex and its replacement by the distal lateral pinna assuming a terminal position—was found to have evolved separately in each of the four species with this kind of leaf apex. A scanning electron microcope study of the spores revealed five types, and a transformation series for these different types is proposed. Characters of spore morphology and heteroblastic leaf development agreed with many of the clades in the phylogenetic tree. This study represents the first phylogeny for the genus.     

<Emphasis Type="Italic">Clitopilus reticulosporus</Emphasis>, a new species with unique spore ornamentation,its phylogenetic affinities and implications on the spore evolution theory

Clitopilus reticulosporus (Entolomataceae, Agaricales) growing on rotting wood is described as a new species based on collections from Austria and Hungary. Multi-gene phylogenetic analysis of ITS, rpb2, LSU and mtSSU confirms the placement of C. reticulosporus in the Clitopilus-Rhodocybe clade in the Entolomataceae. It is nested within the subclade containing the species with clitopiloid spores (Clitopilus s. str.). Scanning electron microscopy studies demonstrate that the spores of this species have a peculiar reticulate ornamentation resembling an intermediate form between the clitopiloid type with longitudinal ribs, and the rhodocyboid type with irregular bumps and ridges. However, our ancestral character reconstruction suggests that (1) this character state is not an intermediate form and (2) the discovery of this new character state does not have a direct implication on the Entolomataceae spore evolution theory. Our phylogenetic reconstruction uncovered, at least, three distinct lineages in the Clitopilus s. str. clade, and suggest that sect. Clitopilus is monophyletic, while sect. Schyphoides and sect. Pleurotelloides are not.     

Synopsis of the species of Myxobolus Bütschli, 1882 (Myxozoa: Myxosporea,Myxobolidae) described between 2005 and 2013

A synopsis of the species of Myxobolus Bütschli, 1882 (Myxozoa, Myxosporea, Myxobolidae) described between 2005 and 2013 is presented, including 112 nominal species. For each species the most important morphological and morphometric features are indicated in tabulated format. Included are also accession numbers for molecular data (when available), site of the infection within the host, features of the vegetative stage, organ infected, etc., plus a full bibliography of the original records for these species.     

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

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

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.