Morphometrical and molecular characterization of Gyrodactylus cichlidarum (Gyrodactylidae) from Astronotus ocellatus (Cichlidae) in Iran

Gyrodactylus is a small monogenean ectoparasite that lives on the skin and fins of most of the world's fish species. Gyrodactylus appears to be one of the most prevalent parasites of ornamental fish. The current study aimed to identify the species of one of the most species-rich genera of the monogenean flatworms (Gyrodactylus) in one of the popular ornamental fish (Astronotus ocellatus) in Iran. In the present study, Gyrodactylus species identification was made based on the morphometrical and molecular analysis. The morphometrical identification was performed using the measurements and drawings of opisthaptoral hard parts of the parasites. Molecular species analysis was utilized by polymerase chain reaction of a partial sequence of the 5.8S region of ribosomal DNA and partial sequence of internal transcribed spacer 2 of ribosomal DNA. Based on morphometrical analysis and sequencing, the Gyrodactylus specimens were described as Gyrodactylus cichlidarum. This is the first report of G. cichlidarum from oscar fish (Astronotus ocellatus).