During a survey of birds from Argentina, two species of Digenea, one of them new, were found parasitizing the great antshrike, Taraba major (Vieillot) (Aves: Thamnophilidae). The strigeid, Strigea orbiculata sp. n. is characterized by having a body plump, a copulatory bursa without a membraneous fold ('Ringnapf'), entire testes, eggs with miracidia with eye-spots, by the arrangement of vitelline follicles in the forebody, which are densely distributed from its anterior edge, and by the absence of a neck region in the hindbody. Among the known Neotropical species of Strigea Abildgaard, 1790, only five share with Strigea orbiculata sp. n. the body shape and the distribution of vitelline follicles in the forebody: Strigea caluri Dubois, 1962, S. elliptica (Brandes, 1888), S. inflecta Lunaschi et Drago, 2012, S. nugax Szidat, 1928 and S. sphaerocephala (Westrumb, 1823 nec Brandes 1888). However, S. caluri can be easily distinguished by having a membraneous fold in the copulatory bursa originated from ''Ringnapf'', and multilobed testes. Strigea elliptica differs mainly by having a well developed ''Ringnapf'' and the remaining species differ principally by metrical characters. The dicrocoeliid, Lyperosomum oswaldoi (Travassos, 1919) is reported for the first time from Argentina and T. major represents its new definitive host. The host specificity of Neotropical Strigea spp. is discussed and an updated list of records of their hosts is provided.
A new strigeid digenean, Strigea meridionalis sp. n., is described from the small intestine of the savanna hawk, Buteogallus meridionalis (Latham) (Aves: Accipitridae), from Formosa Province, Argentina. This species is characterised by the absence of a neck region in the hindbody, the presence of entire testes, a copulatory bursa with a membranous fold originated from the muscular ring (Ringnapf) and by the arrangement of vitelline follicles in the forebody. Other two strigeid species collected from the savanna hawk, Strigea elliptica (Brandes, 1888) and Strigea microbursa Pearson et Dubois, 1985, are described and illustrated. Strigea microbursa is reported for the first time from the Neotropical Region and B. meridionalis represents a new host record for S. elliptica. These findings allow us to increase the knowledge of these species, adding new metric and morphological data. A key to the species of the Neotropical Strigea Abildgaard, 1790 is presented including data on their geographical distribution.