AN ELECTROPHORETIC AND MORPHOLOGICAL ANALYSIS OF LABIOSTRONGYLUS (LABIOSIMPLEX) BANCROFTI (JOHNSTON AND MAWSON, 1939) (NEMATODA, CLOACINIDAE), FROM MACROPODID MARSUPIALS, WITH THE DESCRIPTION OF 2 NEW SPECIES

Allozyme electrophoresis was used to compare specimens of Labiostrongy lus (Labiosimplex) bancrofti from two species of Australian macropodid s, Macropus dorsalis and M. parryi, with a related species, L. (Labiom ultiplex) uncinatus which also infests M. dorsalis. Each nematode was characterised genetically at is enzyme loci. The level of fixed geneti c differences detected between L. (Ls.) bancrofti from M. parryi and M . dorsalis (83%) is equivalent to that when each is compared to the mo rphologically distinct species L. (Lm.) uncinatus (89-94%), demonstrat ing unequivocally that the taxon L. (Ls.) bancrofti represents at leas t two species, one in M. parryi and one in M. dorsalis. In addition, m orphological evidence from additional specimens collected from M. parr yi suggested the existence of a third sibling species in this group. A ll three species differ in the shape of the spicule tips; L. (Ls.) ban crofti has longer spicules than either of the two new species. L. (Ls. ) quasibancrofti n. sp. has smaller cephalic papillae, larger oesophag o-intestinal diverticula, a larger genital cone and a longer female ta il than L. (Ls.) turnbulli n. sp. The taxon L. (Ls.) bancrofti consist s, therefore, of three species, L. (Ls.) turnbulli in M. parryi, L. (L s.) quasibancrofti in M. dorsalis, and L. (Ls.) bancrofti found in bot h host species, as well as in four species of rock wallabies.