New records about helminth parasites of the marsh frog, Rana ridibunda ridibunda (Anura: Ranidae) from the north of Iran

A field trials were conducted to assess the helminth parasites of 12 marsh frogs (Rana ridibunda ridibunda) in the Anzali, Astara and Aghbaba regions in the north of Iran in May 1994. Experimental results showed that 83.8% of the Anzali marsh frogs were infected by one or two kinds of metacercarian cysts of digenetic trematodes. The helminth parasites were included Skrjabinoeces breviansa, S. smilis, Gorgodera dollfusi, Opisthioglyphe ranae, Prosotocus confusus, Encyclometra colubrimurorum and Codonocephalus urniger. Frogs collected from the Astara region was infected by the helminth parasites such as Diplodiscus subclavatus, P. confusus, C. urniger and Cosmocerca ornata. There were only one digenetic trematodes cysts such as Pleurogenoides medians in the Aghbaba region. In this paper, except the S. smilis, C. urniger and O. ranae we report 7 new helminth parasites in the north Iranian freshwater system for the first time.