“…Species belonging to the genus Dugesia, sharing very similar external morphology, but consistently diverging at the level of internal genital anatomy and karyology (Benazzi & Benazzi Lentati, 1976), were usually ascribed to the "D. gonocephala group" until the phylogenetic analysis results of De Vries & Sluys (1990-In spite of very numerous morphological studies focusing on species-specific diagnostic traits, karyological analyses are very scant with the exception of several western Palaearctic and Oriental species (Lepori, 1948;Dahm, 1963Dahm, , 1967Benazzi & Banchetti, 1973;Ball, 1974Ball, , 1977Ball, , 1979Bromley, 1974Bromley, , 1977Benazzi & Benazzi Lentati, 1976;Kawakatsu et al, 1976Kawakatsu et al, , 1989Gourbault, 1981;Oki etal, 1981;Pala et al, 1981Pala et al, , 1995Pala et al, , 1999De Vries, 1986, 1988aRibas etal, 1988;Deri etal, 1999). The genus Dugesia is notably common in a wide geographic range from Europe, Asia including many islands of SE Asian countries, Africa, to NE Australia (70 species are known at present; cf.…”