LIBYOSTRONGYLUS DENTATUS N-SP (NEMATODA, TRICHOSTRONGYLIDAE) FROM OSTRICHES IN NORTH-AMERICA, WITH COMMENTS ON THE GENERA LIBYOSTRONGYLUS AND PARALIBYOSTRONGYLUS

Libyostrongylus dentatus sp. n. is described from ostriches on farms f rom North Carolina and Texas. Nematodes were recovered from the poster ior proventriculus and under the koilon lining of the gizzard; the par asites occurred in mixed infections with Libyostrongylus douglassii. T he species is distinguished from congeners by the presence of a promin ent, dorsal, esophageal tooth; in males by the structure of the dorsal ray and spicules; and in females by small eggs (52-62 mu m in length) , a sublateral vulva situated at 93% of the body length from the anter ior, and a strongly curled, digitate, tail with cuticular inflations a t the anus. Conflicts in the generic diagnoses of Libyostrongylus and Paralibyostrongylus were apparent, based on the structure of the dorsa l ray or position of rays 3-5 of the copulatory bursa. These can only be resolved based on phylogenetic analyses of the 11 nominal species r eferred to these genera.