Search

A new species of Myxobolus parasitizing the arterial bulb and cardiac musculature of the freshwater fish Pimelodus ornatus Kner, 1858, from the Arari river in the municipality of Cachoeira do Arari, island of Marajó, Pará, Brazil, was described. In the present study, the observed prevalence of myxozoan parasites in the heart tissue of the hosts was 20% (6/30). The myxozoans observed had mature biconvex spores, slightly rounded, an anterior end with two pyriform polar capsules and a posterior end with very evident sporoplasm, measuring 8 ± 0.2 μmin length. The spore width was 5.8 ± 0.4 μm, with a thickness of 3.4 ± 0.2μm. The length of the polar capsules was 3.6 ± 0.3 μm and the width was 1.2 ± 0.2μm, with 6 to 7 turns of the polar filament. The divergences observed, regarding the morphometric and genetic structure of SSU rDNA, in relation to other Myxobolidae already described in the literature, confirm the description of the new species Myxobolus rangeli n. sp. Resumo Descrição de uma nova espécie de Myxobolus que parasita o bulbo arterial e a musculatura cardíaca do peixe de água doce Pimelodus ornatus Kner, 1858, do rio Arari, no município de Cachoeira do Arari, ilha de Marajó, Pará, Brasil. No presente estudo, a prevalência observada de parasitas mixozoários no tecido cardíaco dos hospedeiros foi de 20% (6/30). Os mixozoários observados apresentavam esporos maduros biconvexos, levemente arredondados, extremidade anterior com duas cápsulas polares piriformes e extremidade posterior com esporoplasma bem evidente, medindo 8 ± 0,2 μm de comprimento. A largura do esporo foi de 5,8 ± 0,4 μm, com espessura de 3,4 ± 0,2 μm. O comprimento das cápsulas polares foi de 3,6 ± 0,3 μm e a largura foi de 1,2 ± 0,2 μm, com 6 a 7 voltas do filamento polar. As divergências observadas, quanto à estrutura morfométrica e genética de SSU rDNA, em relação a outros Myxobolidae já descritos na literatura, confirmam a descrição da nova espécie Myxobolus rangeli n. sp.

Panel with potentially amplifiable minisatellite loci for Arapaima gigaspanel with potentially amplifiable minisatellite loci for Arapaima gigas

Panel polymorphic microsatellite markers for the Arapaima gigas

Panel with potentially amplifiable microsatellite loci for Arapaima gigas

Panel with potentially amplifiable microsatellite loci for Arapaima gigas

Panel polymorphic microsatellite markers for the Arapaima gigas

Myxobolus arariensis n. sp. ( Figs 1���3) Morphological description. Mature spores are ellipsoidal in shape, with a mean length of 11.4 ��m (10.7��� 12.6) and mean width of 7.2 ��m (6.4���7.9). Each spore contains two polar capsules (PCs) of equal size 4.0 �� 0.7 ��m (3.6���4.3) long and 1.9 �� 0.36 ��m (1.7���2.2) in width (Figs. 1B and 3) (Table 1). Type host. Rhamdia quelen (Quoy & Gaimard 1824) Site of infection. epaxial and hypaxial layers of the musculature, with plasmodia containing numerous spores. Type-locality. Arari River, Cachoeira do Arari on Maraj�� Island, northern Brazil. Etymology. The species was named for the locality of origin, the Arari River in northern Brazil. Specimens deposited. Microscope slides containing spores from the muscle layer, prepared using the paraffin technique, stained in Gutierrez and mounted in Entellan were deposited in the International Protozoan Type Collection of the National Institute for Amazonian Research (INPA) in Manaus, Amazonas state, Brazil (catalog number: INPA /027). The partial 18S rDNA sequence was deposited in GenBank under accession number MG572219. Prevalence. Three of twenty-five R. quelen examined 12% (3/25) had plasmodia of an unknown parasite from the genus Myxobolus. Remarks. M. arariensis can be differentiated morphologically from all seven Myxobolus species known to infect the muscle tissue of freshwater fish (Table 1). The new species can be distinguished from M. tasikkenyirensis (Sz��kely et al. 2009a) and M. groenlandicus (Buchmann et al. 2012) by the different shape of the anterior extremity of the spores, and from M. leptobarbi (Sz��kely et al. 2009b) by the same trait. The length of M. arariensis (11.4 ��m) is most similar to that of M. lentisuturalis (Dykov�� et al. 2002), which is 11.8 ��m long, whereas M. omari (Sz��kely et al. 2009b) is the shortest species, at 7.9 ��m. Anomalous spores with a caudal filament and lack of ornamentation on the external wall were also observed (Fig. 2C). Histology. The histological analysis revealed the presence of cysts of M. arariensis lodged in the fibers of the skeletal muscles (Fig. 4). Immature spores were observed in the most external layer of the cyst, with mature spores being found more internally. The cyst wall is thick and fibrous, and the adjacent musculature was compressed, with the sarcoplasm frayed, and evidence of a necrotic reaction caused by this compression. Molecular data. In the molecular analysis, the specific pair of myxozoan primers (MC5-MC3) amplified 974 bps of the 18S rDNA gene of the spores obtained from the plasmodia found infecting the musculature of R. quelen. The BLAST search of the 18S rDNA sequence data (974 bps) of the Myxobolus species parasitizing R. quelen found no identical myxozoan sequence in GenBank, although a similarity of at least 85% was found with four species: Myxobolus cordeiroi (KF296353, 90% similarity), Myxobolus sp. GA2 (KU 170935, 86%), Myxobolus lentisuturalis (AY278563, 85%), and Myxobolus cultus (HQ613409, 85%). The optimal evolutionary model for maximum likelihood (ML) and Bayesian analysis were determined by jModelTest 3.0 (Posada, 2008) which identified the best evolutionary model as the general time reversible model (GTR + I + G), using Akaike information criteria. Nucleotide frequencies were estimated from the data (A = 0.2574, C = 0.1848, G = 0.2625, T = 0.2326) and six rates of nucleotide substitution calculated as AC = 0.8659, AG = 2.6388, AT = 1.7658, CG = 0.4883, CT = 3.4814, GT = 1.000. The proportion of invariable site was 0.5565 and the alpha value of gamma distribution parameter 0.3612. Two independent runs were conducted with 4 chains for 2 million generations for Bayesian analysis. Ceratomyxa shasta (AF001579) e C. amazonensis (KX236169) was designated as outgroup. Phylogenetic trees were sampled every 100 generation. Characteristics of some Myxobolus species. Abbreviations: FC = Capsule Formate, SL, spore length, SW = Spore Width, PCL = Polar Capsule Length, PCW= Polar Capsule Width. PC = relative size of the polar capsules (= = equal in size, # = different in size, or equal and different); All measurements are given in micrometers. In the phylogenetic analysis, trees generated by Bayesian Inference (BI) had similar topologies, but with different support values at some nodes. A strong clustering tendency was found according to phylogenetic affinities. The phylogram indicated the existence of three clades, A, B and C the first paraphyletic, includes species of Henneguya and Myxobolus formed by the freshwater and marine water (Mugiliformes). The clade A subdivide into 2 subclades, A1 and A2. The subclade A1 shows M. arariensis grouping on the same branch with M. cordeiroi and with adjacent subclade with M. marajoensis species, having same host. The other subclade, A2 have the presence of the Myxobolus and Henneguya, corroborating the characteristic of the Myxobolus genus to be paraphyletic. On the other hand, the clades B and C have agrouped species of various Myxobolus parasites of freshwater fish belonging to same and different Order (Table 3). The type of host defines a well-supported freshwater and marine water clade of Myxobolus and Henneguya (clade A) that infect fish of the orders Siluriformes, Mugiliformes, Characiformes and Perciformes. However, M. arariensis, which infects silurids, evolved independently from the Myxobolus subclade A1 that infects fish of the families Pimelodidae and Ictaluridae. The tree presented a similar topology for the other clades, clustering according to the taxonomic order of the host. The clade B groups Myxobolus, of the orders Cypriniformes and Perciformes. The clade C is also compounded by Myxobolus groups that parasitize hosts of the different orders Salmoniformes, Siluriformes, Characiformes and Cypriniformes (Fig. 5). The p distance found between M. arariensis and any other Myxobolus species that had Siluriformes as host ranged from 11.6 to 22.1% (Table 2), which reinforces the definition of M. arariensis as a new species. The myxosporidian sequences analysed are showing in the Table 3. ������continued on the next page, Published as part of Abrunhosa, Jacqueline, Sindeaux-Neto, Jose L., Santos, Sidney, Hamoy, Igor & Matos, Edilson, 2018, A new species of myxozoa in the skeletal striated musculature of Rhamdia quelen (Quoy & Gaimard) (Siluriforme: Pimelodidae) Amazonian fish, Maraj�� island, Brazil, pp. 164-176 in Zootaxa 4482 (1) on pages 166-172, DOI: 10.11646/zootaxa.4482.1.8, http://zenodo.org/record/1453193, {"references":["Buchmann, K., Skovgaard, A. & Kania, P. W. (2012) Myxobolus groenlandicus n. sp. (Myxozoa) distorting skeletal structures and musculature of Greenland halibut Reinhardtius hippoglossoides (Teleostei: Pleuronectidae). Diseases of Aquatic Organisms, 98, 133 - 141. https: // dx. doi. org / 10.3354 / dao 02437"]}

Myxobolus bragantinus n. sp. Host: Mugil rubrioculus Harrison et al. 2007. Locality: Municipality of Bragan��a, northeastern Par��, Brazil. Site of infection: Gill filaments Plasmodial type: Intrafilamental-epithelial (FE) Prevalence: 60% (90/150). Type material: Slides containing cysts with spores in the gill filament, which were processed by embedding in paraffin, and stained with Ziehl-Neelsen (Fig. 2a). These specimens were deposited in the International Protozoan Type Specimen Collection at the Brazilian National Institute of Amazonian Research (INPA) in Manaus, Amazonas, Brazil (catalog number: INPA 34). Etymology: The species name, bragantinus, refers to the collection site, at Bragan��a, in the Brazilian state of Par��, where the microparasite was discovered and described for the first time. The histological analysis shows cysts lodged internally in the gill filament, located in the intermediate portion, causing hypertrophy, a moderate increase in the size of the filaments, associated with the presence of the parasitic cysts of Myxobolus bragantinus n. sp., and a thickening of the cyst wall (Fig. 2 a���b). Under light microscopy, the ZN-stained slides revealed spores characteristic of Myxobolus (Lom & Dykova 2006), featuring polar capsules (see Fig. 2b). The location of the parasite in the gills, is known as the ���intrafilamental-epithelial��� (FE) type., Published as part of Cardim, Joyce, Silva, Diehgo, Hamoy, Igor, Matos, Edilson & Abrunhosa, Fernando, 2018, Myxobolus bragantinus n. sp. (Cnidaria: Myxosporea) from the gill filaments of the redeye mullet, Mugil rubrioculus (Mugiliformes: Mugilidae), on the eastern Amazon coast, pp. 177-187 in Zootaxa 4482 (1) on pages 179-181, DOI: 10.11646/zootaxa.4482.1.9, http://zenodo.org/record/1440542, {"references":["Harrison, I. J., Nirchio, M., Oliveira, C., Ron, E. & Gaviria, J. (2007) A new species of mullet (Teleostei: Mugilidae) from Venezuela, with a discussion on the taxonomy of Mugil gaimardianus. Journal of Fish Biology, 71 (Supplement A), 76 - 97. https: // doi. org / 10.1111 / j. 1095 - 8649.2007.01520. x.","Lom, J. & Dikova, I. (2006) Myxozoan genera: definition and notes on taxonomy, life-cycle terminology and pathogenic species. Folia Parasitologica (Praha), 53 (1), 1 - 36. http: // dx. doi. org / 10.14411 / fp. 2006.001"]}

Abrunhosa, Jacqueline, Sindeaux-Neto, Jose L., Santos, Sidney, Hamoy, Igor, Matos, Edilson (2018): A new species of myxozoa in the skeletal striated musculature of Rhamdia quelen (Quoy & Gaimard) (Siluriforme: Pimelodidae) Amazonian fish, Marajó island, Brazil. Zootaxa 4482 (1): 164-176, DOI: https://doi.org/10.11646/zootaxa.4482.1.8