POLYMORPHISM IN THE OSTERTAGIINAE LOPEZ-NEYRA, 1947 AND COMMENTS ON THE SYSTEMATICS OF THESE NEMATODES

A list of 19 polymorphic species of the genera Ostertagia, Orloffia, T eladorsagia, Marshallagia and Spiculopteragia is presented. The morphs of the polymorphic species in question have identical females and sho w similarities in some male features, e.g. the structure of the oesoph agus, the synlophe and the shape of the rays of the copulatory bursa. However, they differ by characters which are recognised as generic fea tures, e.g. the structure of spicules, gubernaculum and genital cone. The presence or lack of minor morphs is a generic feature in the Oster tagiinae. Each polymorphic genus has a defined type of minor morph.