[The data on helminth infestation of the Siberian tree frog (Rana amurensis Boulenger, 1886) in the western boundary of the range].

Helminth species composition and infection rates of the Siberian tree frog Rana amurensis in Western Siberia were studied. Four species of helminthes--nematodes Rhabdias bufonis, Oswaldocruzia filiformis, Cosmocerca ornata and the trematode Haplometra cylindracea were found. Prevalence of helminths in the Siberian tree frog is 100%, and mean abundance is 27.5 +/- 4.8. Helminth species richness in the Siberian tree frog in the western periphery of their distribution area is lower than in the center of the range, in Yakutia and Transbaikalia, and is approximately equal to that in the northeastern boundary of the range, in Magadan Province. R. bufonis, a highly pathogenic nematode species, dominates in prevalence and abundance in the Siberian tree frog in Western Siberia as well as in other parts of the geographical range of this species.