Deviation from the Groundplan: a unique new species of freshwater planarian from South Brazil (Platyhelminthes, Tridadida, Paludicola)



The species Girardia biapertura Sluys, sp. nov. is described from the state of Rio Grande do Sul, Brazil. A unique derived character distinguishes this species from its congeners and all other planarians known to date, namely separate openings of the vasa deferentia at the tip of the penial papilla. Present knowledge on the distribution of Girardia species in Rio Grande do Sul is summarized.