Przywry ptaków Dolnego Śląska. III. Urotocus rossitensis (Muhling, 1898) - nowy dla Polski gatunek przywry pasożytującej u ptaków wróblowatych

During the studies on trematode fauna of birds from Lower Silesia, the rare species - Urotocus rossitensis (MÜHLING, 1898) - was found. It parasitized in the bursa Fabricii of Sylvia borin, Erithacus rubecula and Turdus philomelos, and in the cloaca of Turdus merula. All these birds are new hosts for U. rossitensis which was recorded for the first time in Poland. It is worth mentioning that the localization of this trematode in the cloaca of T. merula is nontypical, since the parasite has underdeveloped suckers. Morphological and biometrical data give us new information about variability of U. rossitensis. They allow the author to support WILLIAMS' (1960) proposition to include U. fusiformis MCINTOSH, 1935 and U. tholonetensis TIMON-DAVID, 1955 among the synonyms of Urotocus rossitensis (MÜHLING, 1898).