Molecular phylogeny provides new insights on the taxonomy and composition of Looss, 1899 (Digenea, Dicrocoeliidae) and related genera.

Looss, 1899 is one of the largest genera of the Dicrocoeliidae and is one of the best examples of the systematic complexity and taxonomic instability within this family. We present the molecular analyses based on novel sequences of nuclear and mitochondrial genes obtained from 56 isolates of adult flukes and larval stages of dicrocoeliids belonging to , as well as previously available sequence data. According to obtained results we propose to return and into , and to recognize as a synonym of . Our study shows that commonly occurs in Europe in corvids as well as in several species of migratory songbirds, e.g. . At the same time, the Turdidae appear to host a distinct species of . The phylogenetic analysis has clearly demonstrated the paraphylepic nature of and indicated the need of its thorough revision preferably using specimens from type hosts and type territories of nominal species. In addition, inclusion of numerous not yet sequenced dicrocoeliid genera into future phylogenetic studies is necessary to clarify the interrelationships of taxa within the family and stabilize its system.