The first finding of Macracanthorhynchys catulinus in Mongolian toad Bufo raddei

Acanthocephalan Macracanthorhynchus catulinus was recorded in Mongolian toad Bufo raddei in the Selenga River Basin, Western Transbaikalia. 272 sp. of Mongolian toad, 228 sp. of Siberian frog, 50 sp. Siberian salamander, 21 sp. moor frog, 30 sp. Far Eastern frog was examined for parasitological research. Sampling, fixation and laboratory processing was performed by conventional methods. Acanthocephalan was in the larval stage - the stage of late acanthella, without capsule. The length of the larvae reaches 1,98 mm, width - 0,97 mm. The primordia of the internal organs were difficult to distinguish. Differentiation was conducted by well-defined proboscis with hooks. Hooks were arranged in six spiral rows with six hooks in a row. The largest hooks were front, they have an anterior and posterior appendages of root, rear hooks have a root forming a plate. M. catulinus was detected in the intestine of toad, it was not attached to the intestine wall. Mongolian toad is a reservoir host of M. catulinus. The low level of infection (prevalence 0,37 %; abundance 0,004 sp.) indicates the random character of the infection by this acanthocephalan. M. catulinus is the first discovery of the acanthocephalan in amphibians of Transbaikalia and the first discovery of the acanthocephalan in the Mongolian toad.