Abstract
A total of 333 vials of nematodes collected from three species of Isoodon (representing three individuals of I. auratus, 63 of I. fusciventer and 92 of I. obesulus) held in the Australian Helminthological Collection of the South Australian Museum were examined. Nematodes were identified and the nematode assemblages of the three hosts were compared with each other and with the assemblage of Isoodon macrourus. Two fully identified species were recovered from I. auratus, eight from I. fusciventer and 14 from I. obesulus. None of the species occurred in all three hosts; Labiobulura inglisi (Subuluridae), Peramelistrongylus skedastos (Dromaeostrongylidae) and Asymmetracantha tasmaniensis (Mackerrastrongylidae) all occurred in I. fusciventer and I. obesulus. Only Pe. skedastos was also found in I. macrourus. Sorensen's index of similarity, 27.2 %, showed that I. fusciventer and I. obesulus did not have similar nematode communities and neither were their communities similar to that of I. macrourus, 17.1 % and 39.0 % respectively. Labiobulura inglisi and Linstowinema inglisi were the dominant nematodes in the assemblage of I. fusciventer and La. inglisi was dominant in I. obesulus. The two hosts had nematode assemblages with unique species profiles; one species of Linstowinema in I. fusciventer, three in I. obesulus; a species of Physaloptera in I. obesulus, none in I. fusciventer; four species of strongylid; Asymmetracantha tasmaniensis the most prevalent in I. fusciventer, Peramelistrongylus skedastos the most prevalent in I.obesulus. The size of the geographic range is a probable determinant of the species richness of the nematode assemblages.