A new species of Centrorhynchus (Acanthocephala, Centrorhynchidae) endoparasite of Guira guira (Aves, Cuculidae) from Argentina

Centrorhynchus guira n. sp. is described from the guira cuckoo, Guira guira (Gmelin) (Cuculiformes: Cuculidae), from Argentina. This new species is characterized by the proboscis armament with 32 longitudinal rows (29 with 18 hooks per row and 3 with 19 hooks per row) and by the following hook pattern per row: 8–9 true hooks, 4 transitional hooks with lateral alate processes, and 6 spiniform hooks. The presence of transitional hooks is shared with five other Neotropical species in the genus: C. polymorphus, C. albidus, C. microcephalus, C. kuntzi and C. crotophagicola. Among these species, C. guira n. sp. most closely resembles C. kuntzi in having transitional hooks with lateral alate processes, however differs in the number of hooks per row and spiniform hooks. This is the first record of the genus Centrorhynchus parasitizing Argentinean birds. A key to the species of the Neotropical Centrorhynchus Lühe 1911 is presented.