THE GENUS DUGESIA IN AUSTRALIA, WITH ITS PHYLOGENETIC ANALYSIS AND HISTORICAL BIOGEOGRAPHY (PLATYHELMINTHES, TRICLADIDA, DUGESIIDAE)

The new species Dugesia notogaea Sluys & Kawakatsu, sp. n. is describe d from Queensland, Australia, representing the first record of the gen us Dugesia for that continent. A phylogenetic analysis of the 68 speci es of Dugesia resulted in the discovery of a new apomorphy for the gen us, and a cladogram showing two major phyletic groups. The distributio nal range of one group has a western accent, whereas that of the other group has an eastern emphasis; the ranges of these two groups overlap in Africa and the Mediterranean region. We attempt to determine the a ncestral area for both the Dugesiidae and Dugesia. A scenario for the historical biogeography of the genus Dugesia is discussed. In this sce nario it is presumed that the geological history of the Australasian r egion enabled Dugesia's from southeast Asia to colonize northern Austr alia. (C) 1998 The Norwegian Academy of Science and Letters.