The marine myxosporean Sigmomyxa sphaerica (Thélohan, 1895) gen. n., comb. n. (syn. Myxidium sphaericum) from garfish (Belone belone (L.)) uses the polychaete Nereis pelagica L. as invertebrate host

Sigmomyxa sphaerica (Thélohan, 1892) gen. n. (Myxozoa, Myxosporea) with myxosporean stages in the gall bladder of Belone belone (L.) (Teleostei, Belonidae) uses the polychaete Nereis pelagica L. (Nereidae) from shallow water in the northern Øresund, Denmark, as invertebrate host. The nearly spherical tetractinomyxon-type actinospores of S. sphaerica differ from those of two species of Ellipsomyxa which also use Nereis spp. as invertebrate host. Pansporocysts of S. sphaerica were not seen. S. sphaerica is redescribed on the basis of myxospore stages from B. belone and actinospores from N. pelagica, and the phylogenetic affinities examined on the basis of ribosomal small subunit gene sequences. S. sphaerica is closest related to Ellipsomyxa spp., and is not congeneric with morphologically similar Myxidium spp. from gadids. This is the fifth elucidated two-host life cycle of a marine myxozoan

The morphological and molecular characterization of Myxobolus khaliji n. sp (Myxozoa: Myxosporea) from the double bar seabream Acanthopagrus bifasciatus (ForsskAyenl, 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) mu m long, 6.3 +/- 0.6 (5.1-7.4) mu m 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) mu m long and 3.2 +/- 0.2 (2.1-4.2) mu m 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.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) mu m long, 6.3 +/- 0.6 (5.1-7.4) mu m 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) mu m long and 3.2 +/- 0.2 (2.1-4.2) mu m 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