While the reality of the taxon Turbellaria has been called into question lately, turbellarians are nevertheless the subject of active research by a sizable group of biologists. Turbellarians are relatives of the major groups of parasitic platyhelminthes - monogeneans, digeneans, and tapeworms - and most are free-living. Because the ancestors to the major parasitic groups would be classified as turbellarians, strict application of princi ples of phylogenetic systematics dictates that the Turbellaria is not properly considered a separate taxon; i. e., it is, in the parlance of systematics, a...