Morphostructural data and phylogenetic relationships of a new cnidarian myxosporean infecting spleen of an economic and ecological important bryconid fish from Brazil

A new cnidarian myxosporean infecting the spleen of an economic and ecological important bryconid fish (Salminus franciscanus) is described based on integrative taxonomic approach including morphological, ultrastructural, biological traits, geography, molecular data phylogenetic analysis. In a total thirty specimens examined, nineteen (63.3%) were infected by undescribed parasite species belonging to genus Myxobolus. Plasmodial development was asynchronous, with young in periphery mature myxospores central area without projections microvilli plasmodial wall. Mature ovoid shape measured 7.9 ± 0.2 μm (7.6–8.1 μm) length 5.4 0.1 (5.0–5.6 width. The two polar capsules equal size, occupying little more than half myxospore body, measuring 4.0 (3.9–4.1 1.7 (1.5–1.8 tubules coiled six turns, perpendicular long axis capsule. Phylogenetic analysis placed within clade containing nine myxobolid from South American characiforms appears as close Myxobolus pantanalis. Nevertheless, sequences M. pantanalis have large genetic divergence 13.5% their SSU rDNA. light differences observed taxonomy, we confidently considered that this isolate myxosporean, douradae n. sp., increasing knowledge diversity enigmatic group cnidarians.