Morphological and genetic differences among actinosporean stages of fish-parasitic myxosporeans (Myxozoa): difficulties of species identification.

The occurrence and morphology of actinosporean stages of myxosporeans were studied at a fish farm and in the River Tisza in Hungary. The 43 samples sequenced belonged to 10 'genotypes', from which six were determined as new actinosporean types. Based on DNA sequence analysis, the assumed actinosporean developmental stages of four myxozoan species were identified.