AN ELECTROPHORETIC AND MORPHOLOGICAL ANALYSIS OF LABIOSTRONGYLUS (LABIOMULTIPLEX) UNCINATUS (NEMATODA, CLOACINIDAE), WITH THE DESCRIPTION OF A NEW SPECIES, LABIOSTRONGYLUS-CONTIGUUS, FROM MACROPUS-PARRYI (MARSUPIALIA, MACROPODIDAE)

An electrophoretic study was conducted on Labiostrongylus (Labiomultip lex) uncinatus, nematodes that occur in the stomachs of two species of Australian macropodid, Macropus dorsalis and M. parryi. The allelic p rofiles of these nematodes were compared to those of a morphologically distinct species, L. (Lm.) billardierii, which infests Thylogale bill ardierii. Nematodes were genetically characterized at 17 enzymes encod ing a presumptive 18 loci. The results revealed the existence of two s pecies, one in M. dorsalis and the other in M. parryi, that had fixed genetic differences at 72% of loci. This level of fixed difference bet ween these species is equivalent to that when each is compared to L. b illardierii (87-89%). The new species in M. parryi, Labiostrongylus co ntiguus n. sp., is described herein. A morphological comparison with L . uncinatus revealed slight but consistent differences in the morpholo gy of their anterior end; namely, rectangular rather than conical shap ed lateral lips, small inconspicuous, not larger hook-shaped cephalic papillae, and convex rather than flat floor of the buccal capsule for L. (Lm.) contiguus as compared with L. (Lm.) uncinatus. Differentiatio n of L. contiguus from L. uncinatus is more clearly demonstrated by bi ochemical characters than morphological. ones.