ELECTROPHORETIC COMPARISON OF RUGOPHARYNX LONGIBURSARIS KUNG AND R-OMEGA BEVERIDGE (NEMATODA, STRONGYLOIDEA), WITH THE DESCRIPTION OF R-SIGMA N-SP FROM PADEMELONS, THYLOGALE SPP (MARSUPIALIA, MACROPODIDAE)

An electrophoretic comparison of the nematodes Rugopharynx longibursar is and R. omega, both from Macropus rufogriseus in south-eastern Austr alia, revealed fixed genetic differences at 4.5% of the 23 enzyme loci examined. The electrophoretic data do not therefore reject the null h ypothesis that the two taxa are conspecific. R. longibursaris was foun d in Tasmania and in the western mainland population of M. rufogriseus , while R. omega occurred only in the eastern mainland population. Imp lications for the taxonomic status of the western host population are considered. Specimens formerly assigned to R. omega, from Thylogale st igmatica from Queensland, were found to differ at 45.0% of enzyme loci from specimens from M. rufogriseus. Morphological examination reveale d differences in the shape of the buccal capsule, the position of the deirid, the morphology of the spicule tip and the presence of a gubern aculum. A new species, R. sigma, is erected for specimens from T. stig matica, T. thetis and T. calabyi.