On the taxonomic status of Dugesia gonocephala and Dugesia subtentaculata (Turbellaria, Tricladida, Paludicola)

The taxonomic status of Dugesia (Dugesia) gonocephala (Dugès, 1830), the type-species of the genus Dugesia Girard 1850, and the closely related species Dugesia (Dugesia) subtentaculata (Draparnaud, 1801) have never properly been assessed. Dugesia subtentaculata has usually been regarded as a synonym of D. gonocephala, especially for its asexual races. In order to assess the status of the two species, studies have been carried out on material from the surroundings of Montpellier, southern France, from which the type-material of the two species originated. It is concluded that both are valid taxa and neotypes have been designated. Dugesia gonocephala is the common European species, whereas D. subtentaculata has a specifically Mediterranean distribution. Dugesia iberica Gourbault & Benazzi, 1979, originally described from Spain and Mallorca, is conspecific with this latter species. The morphological and karyological characteristics of the two species and of several fissiparous races belonging to the subgenus Dugesia are discussed.