Three new species of Syphacia (Syphacia) (Oxyurida: Oxyuridae) from Queensland, Australia, and a key to the species present in the Australian bioregion

Three new species of Syphacia Seurat 1916 (Oxyurida: Oxyuridae) are described from rodents (Rodentia: Muridae) in Queensland, Australia. Syphacia (Syphacia) helidonensis n. sp. from Pseudomys gracilicaudatus (Gould 1845) can be distinguished from all other species by a suite of characters including an oval-shaped cephalic plate, elongated laterally with dorso-ventral constriction at the level of laterally placed amphids and cephalic papillae, lateral but not cervical alae, and a single pair of postanal papillae. Syphacia (Syphacia) boodjamullaensis n. sp. from Zyzomys argurus (Thomas, 1889) also has an oval-shaped cephalic plate, elongated laterally with dorso-ventral constriction at the level of laterally placed amphids and cephalic papillae, a single pair of postanal papillae, neither cervical nor lateral alae, and spicule 77 µm long. Syphacia (Syphacia) carnarvonensis n. sp. from Pseudomys delicatulus (Gould, 1842) with an oval-shaped cephalic plate, elongated laterally with dorso-ventral constriction at level of laterally placed amphids and cephalic papillae and a single pair of postanal papillae, also has both cervical and lateral alae, small body size, males 690–865 µm, and eggs 77–86 µm long, 24–29 µm wide. A key to the species of Syphacia from the Australian Bioregion is given, and the potential for as yet undiscovered species in the region is discussed.