A concise history of the Ostertagiinae Lopez-Neyra, 1947 (Nematoda: Trichostrongyloidea) and a discussion on its composition.

After a historical introduction to the Ostertagiinae and several revisions of this group, it is proposed that the subfamily shall contain seven genera: Ostertagia, Hyostrongylus, Longistrongylus, Marshallagia, Mazamastrongylus, Spiculopteragia and Teladorsagia. The synonyms of these genera are to be found in the literature. In this proposal the genus Hyostrongylus should belong to the Ostertagiinae though it has probably an intermediate position between the Ostertagiinae and Graphidiinae. Cervicaprastrongylus and Tunisostertagia are regarded as synonyms of Hyostrongylus and Ostertagia respectively. The position of Ostertamia and Trichostrongyella is not clear but they could have their closest affinities with Teladorsagia and Mazamastrongylus respectively. The origin of the subfamily and the relationships of the genera with regard to their preferences for host groups and to their geographical distribution are discussed.