Two new species of Dugesia (Platyhelminthes, Tricladida, Dugesiidae) from the Yunnan border region, Southwest China.

Two new species of the genus Dugesia from the Yunnan border region, Southwest China, are described by applying an integrative approach, using morphological, histological, and molecular data. Dugesia repanda Chen & Dong, sp. nov. is characterized by the following features: symmetrical openings of the oviducts into the bursal canal; an upward curving, highly asymmetrical penis papilla; highly elongated and muscularised seminal vesicle of which the major portion is located considerably anterior to the root of the penis papilla; a long connecting duct between the seminal vesicle and diaphragm; a dorsally located penial fold; ejaculatory duct opening subterminally through the dorsal wall of the penis papilla. Dugesialaterocalceata Chen & Dong, sp. nov. is characterized by the following features: hyperplastic ovaries; symmetrical openings of the oviducts; a boot-shaped penis papilla; penis papilla with a dorsal bulge; a connecting duct between the seminal vesicle and diaphragm; ejaculatory duct consistently opening through the right lateral wall of the penis papilla. In the molecular phylogenetic tree, the two new species belong to distinct and independent lineages. Dugesia laterocalceata Chen & Dong, sp. nov. is nested within the Oriental-Australasian clade, whereas D. repanda Chen & Dong, sp. nov. is recovered as a distinct lineage that is sister to the entire Eastern Palearctic-Oriental-Australasian clade.