Primi dati sulla distribuzione geografica di planarie del gruppoDugesia lugubris-polychroa(Turbellaria, Tricladida) in Sardegna, con particolare riguardo alla presenza di una mutazione tetraploide nel fiume Cixerri (Siliqua, Cagliari)

The finding of a Planarian of theDugesia lugubris-polychroagroup characterized by a tetraploid chromosome set of 4n=16; n=4 is reported. This is therefore a tetraploid mutation that has never been reported before in Sardinia.Besides mitotic metaphase plates with 16 chromosomes, which are by far the most frequent (78% of the counts), others containing fewer chromosomes, believed to be derived from segregational mitoses, were also observed.