Molecular phylogeny, systematics and mor phological character evolution in the Balkan Rissooidea (Cae nogastropoda

Sadleriana, Trichonia, Ventrosia) are discussed and illustrated based on the literature and, where necessary, on the presented additional data. These include shell macrocharacters, protoconch sculpture, soft part morphol-ogy and pigmentation, radulae, stomach, female reproductive organs, male reproductive organs. Based on partial sequences of the ribosomal 18S RNA gene, a molecular phylogeny is presented for all the genera, and based on fragments of CO1 gene in mitochondrial DNA, for all except six genera. Based on the Adams con-sensus tree the two gene phylogenies are summarised and systematics of the group is proposed. Adrioinsulana is considered a junior synonym of Pseudamnicola; Parabythinella a junior synonym of Marstoniopsis; a new name: Radomaniola n. gen. is proposed as a replacement name for the preoccupied Orientalina. Litthabitella, morpho-logically and molecularly distinct from the hydrobioids, probably belongs to the Assimineidae. Marstoniopsis belongs to the Amnicolidae, Bythinella to Bythinellidae, Lithoglyphus to Lithoglyphidae, Heleobia to Cochlio-pidae, Bithynia and Parabithynia to Bithyniidae, Emmericia to Emmericiidae. Paladilhiopsis and Bythiospeum be-long to the Moitessieriidae, there being no reason for homologising the two genera. All the other genera be-long to the monophyletic family Hydrobiidae, within which two subfamilies can be distinguished: Hydrobiinae and Sadlerianinae. The latter includes mostly very closely related genera, which makes splitting of this subfamily into more groups of this rank unjustified. The phylogeny of the molecular characters is mapped o