Phyllidiidae (Opisthobranchia: Nudibranchia) from Papua New Guinea with the description of a new species of Phyllidiella

Species of phyllidiid nudibranchs from Papua New Guinea (and other Indo-Pacific regions) are redescribed in this paper. A new species, Phyllidiella backeljaui n. sp., is described and compared with other species of the genus. External characters and internal morphology of the species studied have been examined in detail and illustrated, some of them for the first time such as Phyllidiopsis pipeki. In addition, new locations for Phyllidiella hageni and Phyllidiella zeylanica are reported from Papua New Guinea.