New species of Cloacina von Linstow, 1898 (Nematoda: Strongyloidea) parasitic in the stomachs of wallaroos, Osphranter spp. (Marsupialia: Macropodidae) from northern Australia.

Three new species of the parasitic nematode genus Cloacina von Linstow, 1898 (Strongyloidea: Cloacininae) are described from the stomachs of wallaroos, Osphranter spp. (Marsupialia: Macropodidae), from northern Australia. Cloacina spearei n. sp. is described from O. robustus woodwardi (Thomas) and O. antilopinus (Gould) and is distinguished from congeners by the shape of the cephalic papillae, the shallow buccal capsule, the presence of an oesophageal denticle and the convoluted but non-recurrent vagina in the female. Cloacina longibursata n. sp. also from O. robustus woodwardi and O. antilopinus is distinguished from congeners by the elongate dorsal lobe of the bursa, with the origin of the lateral branchlets posterior to the principal bifurcation, in the features of the spicule tip, the lack of bosses lining the oesophagus and the absence of an oesophageal denticle. Cloacina crassicaudata n. sp., from the same two host species was formerly identified as C. cornuta (Davey & Wood, 1938). Differences in the cephalic cuticle (inflation lacking in the new species), the shape of the cephalic papillae, the dorsal oesophageal tooth and the spicule tips, as well as differences in the sequences of the internal transcribed spacers of the nuclear ribosomal DNA, indicate that this is an independent species. The geographical distribution of this species is disjunct with populations in both the Northern Territory and Queensland. Possible reasons for the disjunct distribution are discussed.