Twelve species of nematode were recovered from the gastrointestinal tract of 115 lizards in the genus Pogona (Agamidae) in Western Australia. Seven species belonged to the Physalopteridae, and three new species are described: Abbreviata pilbarensis, sp. nov., occurs only in the Pilbara region and possesses relatively small dorsal and ventral pseudolabial teeth, inconstant and irregular small denticles on the medial pseudolabial surface, left spicule more than twice the length of the right, vulva with short wide posteriorly directed tubular extension, and thick-shelled eggs; Abbreviata anomala, sp. nov., occurs throughout the State, and possesses small pseudolabia, small dorsal and ventral pseudolabial teeth, an even row of 40-60 small denticles lining the medial pseudolabial surface, left spicule 3-4 times the length of the right, five pairs of pedunculate pericloacal papillae, and females with truncated rounded tail and vulva 3-5% of body length from anterior end; Kreisiella lesueurii, sp. nov., was identified from the south-west, and possesses a row of fine even denticles extending the width of the medial pseudolabial margin, no apical, dorsal or ventral pseudolabial teeth, a restricted area of tubercles on the male ventral tail surface, a short and thick right spicule, four pairs of pedunculate pericloacal papillae, caudal alae not meeting anteriorly and not extending to the tip of the tail, and females with truncated rounded tail and anteriorly placed vulva. The male of Maxvachonia brygooi is described: it possesses lateral alae and differs from M. chabaudi only in the larger size of the gubernaculum and spicules. Other species recorded were Strongyluris paronai, Physalopteroides filicauda, Skrjabinoptera goldmanae, Abbreviata antarctica, Pseudorictularia disparilis, one species of Oxyuroidea, and two species of Trichostrongyloidea.
Concurrent infection with M. brygooi and S. goldmanae was positively correlated, and prevalence and intensity of both species increased with host size, in Pogona minor mitchelli. Prevalence and intensity of infection, and species diversity, were highest in the northern, subtropical parts of the State, and lowest in the drier central and southern inland. Cysts containing physalopteran larvae were present in the stomach wall of many hosts; prevalence and intensity of cysts was highest in the northern area.