[Generic divisions of the Ostertagiinae nematodes].

Of all the morphological characters generally used in classification of the Trichostrongyloidea, the evolution of the caudal bursa seems to illustrate the general evolution of the subfamily most clearly. The Ostertagiinae are divided into two groups. The first group, arising from Graphidium, a parasite of Lagomorphs, is characterized by the isolation of ray 4 and the grouping of ray 2 with ray 3 and ray 5 with ray 6 (arrangement of type 2-1-2). This includes Marshallagia Orloff, 1933, Longistrongylus Le Roux, 1931 and Ostertagia Ransom, 1907. The second group arising from Hyostrongylus (parasites of Lagomorphs and Ungulates--usually primitive), is characterized by the grouping of ray 2 with ray 3, ray 6 with ray 5, and the isolation of ray 6 (arrangement type 2-2-1). This consists of Spiculopteragia (Orloff, 1933), Teladorsagia Andreeva and Satubaldin, 1953 and Gazellostrongylus Yeh, 1956. Evolution in both groups involves the elongation of ray 4 and, especially in the first group, a shortening of rays 8, 5 and 6, as well as the dorsal ray which becomes more and more deeply divided. The following synonymies are recognized: - Bergheia Drozdz, 1965, synonym of Hyostrongylus Hall, 1921. - Grosspiculagia (Orloff, 1933). Ostertagiella Andreeva, 1956, Camelostrongylus Orloff, 1933 and Orloffia Drozdz, 1965, synomyms of Marshallagia. - Bigalkea Monnig, 1931, Bigalkenema Ortlepp, 1963, Kobusinema Ortlepp, 1963, Ostertagia (Costarcuata) Schulz and Kadenazii, 1950, Pseudomarshallagia (Roetti, 1941), synonyms of Longistrongylus. - Gruhneria Sarwar, 1956, Capreolagia Schulz, Andreeva and Kadenazii, 1954, Skrjabinagia (Kassimov, 1942), Muflonagia Schulz, Andreeva and Kadenazii, 1954, Sjobergia Sarwar, 1956, Ostertagiana Dikov, 1963, synomyms of Ostertagia.(ABSTRACT TRUNCATED AT 250 WORDS)