Karyotypes of two European species of the genus Lymnaea with disputable taxonomic status (Gastropoda: Pulmonata: Lymnaeidae)А. V.GarbarauthorА. V.KornіushіnauthorKaryotypes of Lymnaea corvus and L. occulta are studied for the first time and compared to the original data on Ukrainian populations of L. palustris and L. stagnalis. While all the studied species have the same diploid chromosome number (2n = 36), they differ in chromosome morphology. Karyotypes of L. occulta and L. palustris include only biarmed chromosomes (number of arms = 72). In contrast, L. corvus and L. stagnalis have also uniarmed (acrocentric) chromosomes (number of arms = 60 and 62, respectively). Karyological data confirm specific distinctness of L. occulta and L. corvus; however, similarity in the chromosome morphology of the latter species to L. stagnalis is probably based on symplesiomorphies and, thus, cannot support phylogenetic relationship suggested earlier on the basis of anatomical characters.QL Zoology2002Staatliches Museum fur Tierkunde DresdenArticle