Taxonomic Study Of 4 Myxobolus SPP. From The Common Carp (Cyprinus Carpio)

In this study,4 Myxobolus spp. infecting the common carp were collected from Hubei Province and Pengxi River during 2012 to 2013. Their morphological and molecular data were studied. The main results are as follows.1. Redescription of Myxobolus tsangwuensis and Myxobolus acinosus with morphological, histological and molecular data.(1) Myxobolus tsangwuensis Chen,1954 is a common parasite infecting the gills of common carp Cyprinus carpio (L.). Histology showed the plasmodia developed in the capillary network of the gill lamella. Mature spores of M. tsangwuensis were ellipsodal in frontal view and lemon shaped in lateral view, averaging 11.2 ± 0.7 (10.2-12.5) μm × 9.3 ± 0.3 (8.5-10.0) μm × 6.2 ± 0.4 (5.5-7.0) μm. Spores valves were symmetrical and smooth. Occasionally, a small intercapsular appendix was observed. Two polar capsules were pyriform with different sizes, measuring 5.0 ± 0.2 (4.4-5.3) μm × 3.1 ± 0.1 (2.9-3.5) μm and 3.9 ± 0.2 (3.4-4.3)μm x 2.5 ± 0.2 (2.0-2.8) μm, respectively. Polar filaments coiled five to seven turns in large polar capsule and three to four turns in the small polar capsule. Some spores were surrounded by the mucous envelope that was not recorded in the original description. The Myxobolus spores with caudal appendages were also observed in the cysts. Molecular analysis revealed that the present 18S rDNA sequences did not match any available sequences in GenBank and phylogenetic analysis showed M. tsangwuensis was sister to M. basilamellaris and M. musseliusae.(2) Histology showed the plasmodia of Myxobolus acinosus Nie et Li,1973 developed in the capillary network of the gill lamella. Mature spores of M. acinosus were solanum shape in frontal view (some spores concave on one side) and lemon shaped/pyriform in lateral view, averaging 11.2 ± 0.4 (10.4-12.0)μm × 6.4 ± 0.3 (6.0-7.1) μm × 5.8 ± 0.3 (5.0-6.3) μm. Two polar capsules were pyriform with different sizes, measuring 4.7 ± 0.2 (4.1-5.2) μm × 2.7 ± 0.2 (2.4-3.0) μm and 2.5± 0.2 (2.1-2.9)μm × 1.0 ± 0.1 (0.8-1.3)μm, respectively. Polar filaments coiled seven to eight turns in large polar capsule. Molecular analysis revealed that the 18S rDNA sequences of M. acinosus did not match any available sequences in GenBank and phylogenetic inference placed M. acinosus sister to M. longisporus, and the two Myxobolus were within a smaller group containing T. toyamai, T. qadrii and M. koi.2. Myxobolus pseudoacinosus n. sp. and Myxobolus chenmai n. sp were described based on morphological and molecular data.(1) Myxobolus pseudoacinosus n. sp. was found in the gills of commom carp. Mature spores of M. pseudoacinosus n. sp. were solanum shape in frontal view, concave on one side and pyriform in lateral view, averaging 14.1 ± 0.5 (12.9-15.6) μm x6.5 ± 0.3 (6.0-7.3) μm × 5.2-5.8 μm. Two polar capsules were pyriform with different sizes, measuring 6.5 ± 0.3 (6.0-7.2) μm ×3.7 ± 0.2 (3.2-4.2) μm and 3.2 ± 0.3 (2.8-3.8) μm ×1.2 ± 0.1 (0.9-1.4)μm, respectively. Polar filaments coiled six to eight turns in large polar capsule. Molecular analysis revealed that the 18S rDNA sequences of M. pseudoacinosus n. sp. did not match any available sequences in GenBank and phylogenetic inference placed M. pseudoacinosus n. sp. sister to M. acinosus and M. longisporus.(2) Myxobolus chenmai n. sp. was found infecting the fins of common carp. Mature spores of M. chenmai n. sp. were ellipsoidal or rotundity in frontal view, averaging 14.5 ± 0.7 (13.0-15.9)μm × 12.2 ± 0.2 (11.6-12.8) μm. Two polar capsules were pyriform with different sizes, measuring 5.5 ± 0.2 (4.9-5.9) μm x 3.7± 0.1 (3.5-4.0)μm and 4.7± 0.2 (4.2-5.2) μm × 3.1± 0.2 (2.9-3.4) μm, respectively. Polar filaments coiled six to seven turns in large polar capsule and four to five in small polar capsule. Molecular analysis revealed that the 18S rDNA sequences of M. Chenmai n. sp. did not match any available sequences in GenBank and phylogenetic inference placed M. chenmai n. sp. sister to M. basilamellaris and M. musseliusae.