A new species of heligmosomoid nematode Sutarostrongylus johnsoni sp. n., belonging to the sub-family Herpetostrongylinae Skrjabin & Schultz, is described from the small intestine (duodenum) of the red-legged pademelon, Thylogale stigmatica (Gould, 1860) (Marsupialia : Macropodidae), from north-eastern Queensland, Australia. The only other species of the genus S. kirkpatricki Beveridge & Durette-Desset, 1986 occurs in the related host, the red-necked pademelon, T. thetis (Lesson, 1827) in south-eastern Queensland. The new species differs in having longer spicules and asymmetrical spicule tips as well as the presence of a comârete which develops on the right ventral aspect of the mid-region of the body. The synlophe of the new species is unusual in that the inclination of the axis of orientation changes from being oblique in the anterior part of the body to being frontal in the posterior part. The same change may occur in some species of Austrostrongylus Chandler, 1924. Current data suggest that species of Sutarostrongylus are limited to a single genus of host, Thylogale Gray, 1837 and support the suggestion that both nematode species exhibit morphological features which are intermediate between those occurring in Herpetotostrongylinae in dasyurid marsupials and those occurring in macropodid in marsupials.