Acta Zoologica Cracoviensia, 26 (1982 - 1983)
Formation of the turbellarian fauna in a submontane stream in Italy
Abstract:
Turbellarian fauna of a small submontane stream, Monti d´Oltreserchio, Appenine Peninsula, has been studied through 1973 and 1974 from taxonomical and ecological points of view. Amongst 61 identified turbellarian species 12 turned out new. The stream fauna is rich in comparison with other water bodies. A dominating taxonomical group are the Catenulida with the genus Stenostomum as the most important unit. A considerable habitat differentiation is throught to be the main factor responsible for the faunal richness of Turbellaria. From the genetical point of view the investigated fauna of Turbellaria is heterogeneous: terrestrial and marine-originated forms have a remarkable share in comparison with the dominating rest of genuine freshwater species. Some large European turbellarian genera: Gieysztoria, Mesostoma, Phaenocora, Castrada, Olisthanella are poorly represented in the studiem watercourse. General features of the species distribution in the stream biozones and principal habitats have been analyzed and discussed within the ecological succession theory. A considerable role of upper clean stream sections in preserving more stenotopic and old forms has been revealed.
