Molecular confirmation of the life cycle of Thelohanellus hovorkai Achmerov, 1960 (Myxozoa : Myxosporea)

Transmission studies have demonstrated that representatives of the Myxospor ea and the Actinosporea, previously thought to be two classes of the phylum Myxozoa, are different stages of a complex life cycle that requires two di fferent hosts. In this study partial 18S rDNA sequences are provided for th e first time for the myxozoan genus Thelohanellus. Also, sequence conformit y is demonstrated for the myxoosporean and actinosporean stages of Thelohan ellus hovorkai that develop respectively in the common carp, Carassius cara ssius and the oligochaete, Branchiura sowerbyi, confirming the results of e arlier transmission studies that they represent stages of the same species. Such molecular approaches represent a powerful tool in helping to elucidat e myxozoan life cycles as they may preclude conducting numerous time-consum ing transmission studies.