A total of 10 complete rDNA ITS-1 sequences representing 10 different genotypes were obtained from 4 populations of Lymnaea (Stagnicola) palustris palustris from Denmark (Laboratory-bred topotype specimens), France, Germany and The Netherlands, 2 of L. (S.) p. turricula from Austria and Poland, 3 of L. (S.) fuscus from Germany and Spain, and 1 of Catascopia occulta from Poland. Sequences were analysed and compared to those of North American stagnicolines of the genera Catascopia and Hinkleyia. The ITS-1 proved to be a good marker for genus, species, subspecies and population differentation and relationships in stagnicolines. Results suggest that ITS-1 may evolve somewhat faster than ITS-2 in Lymnaeidae. Only a subspecific status is supported for L. (S.) p. turricula when compared to L. (S.) p. palustris. Maximum-parsimony, distance (neighbor-joining) and maximum-like-lihood methods were used in phylogeny reconstruction. The trees showed similar branches supported by very high bootstrap and puzzle values:one branch for the European Stagnicola, including the American stagnicoline species Hinkleia caperata as a basal or sister group, and a branch comprising the European C. occulta together with the North American stagnicolines species of the genus Catascopia.
