Description of five new species of Ixodes Latreille, 1795 (Acari: Ixodidae) and redescription of I. luxuriosus Schulze, 1935, I. steini Schulze, 1935 and I. zaglossi Kohls, 1960, parasites of marsupials, rodents and echidnas in New Guinea Island.

Ixodes acer n. sp., Ixodes giluwensis n. sp., Ixodes mirzai n. sp., Ixodes planiscutatus n. sp. and Ixodes stellae n. sp. (Acari: Ixodidae), are described based on females ex various marsupials (Dasyuromorphia: Dasyuridae, Diprotodontia: Petauridae, Peramelemorphia: Peramelidae), rodents (Rodentia: Muridae) and a bird (Galliformes: Megapodiidae) from Indonesia (Papua Province) and Papua New Guinea. Females of all new species are similar to those of I. luxuriosus Schulze, 1935, I. steini Schulze, 1935 and I. zaglossi Kohls, 1960, but can be distinguished from them and each other by the distinctness of lateral carinae and cervical grooves on the scutum, length of setae on the idiosoma, sculpture of the basis capituli and palpal segment I dorsally, size of the dorsal cornua, shape and sculpture of the palpal segment I ventrally, size of ventral spur on the palpal segment I, dental formula on the hypostome and measurements of various structures and their proportions. For comparative purposes the female of I. luxuriosus, I. steini and I. zaglossi is redescribed and lectotypes for I. luxuriosus and I. steini have been designated. Studied females of I. luxuriosus, I. steini and I. zaglossi were found on marsupials (Dasyuromorphia: Dasyuridae; Diprotodontia: Macropodidae, Petauridae, Phalangeridae, Pseudocheiridae; Peramelemorphia: Peramelidae), rodents (Rodentia: Muridae) and echidnas (Monotremata: Tachyglossidae) in Indonesia (Papua Province) and Papua New Guinea.