Life-cycle and genetic characterization of Astiotrema odhneri Bhalerao, 1936 sensu Cho & Seo 1977 from the Primorsky Region (Russian Far East)

Adult Astiotrema odhneri Bhalerao, 1936 sensu Cho & Seo 1977 were found in the intestine of a freshwater turtle, Pelodiscus sinensis (Wiegmann), from the Komissarovka River Basin, Primorsky Region, Russia. It was established that the first intermediate host of this parasite is a snail, Anisus centrifugops, and that the second intermediate hosts include the snails, Helicorbis sujfunensis and A. centrifugops, tadpoles of the frog Rana dybowskii, and the fish Perccottus glenii. The development of A. odhneri includes the formation of sporocyst and xiphidiocercariae, which is typical for species belonging to Plagiorchioidea. Phylogenetic analysis based on 28S rRNA gene sequences showed that A. odhneri, together with Astiotrema monticellii, form a monophyletic clade that was closer to Opisthorchioidea than to any other taxon represented in the tree. However, phylogenetic analysis without outgroup taxon indicated a high degree of differentiation of Astiotrema from both Plagiorchioidea and Opisthorchioidea.