On the species of the Dugesia gonocephala group (Platyhelminthes, Turbellaria, Tricladida) from Greece

Dugesia gonocephala is a species group, comprising numerous closely related species, which differ from each other in morphological and karyological aspects. In this paper known and presently described species, of the group from the eastern Mediterranean region, are reviewed. Hitherto the triclads of this region have been poorly known in comparison with their western counterparts. Yet there is a wealth of species in the area. Six well-delimited new species of the Dugesia gonocephala group are described and one further species is rescued from synonymy. The wealth of material available has also made possible an assessment of the taxonomic validity of many characters usually considered to be of importance within this difficult group.