Parhadjelia cairinae n. sp. (Nematoda: Habronematoidea: Habronematidae) in the Muscovy duck, Cairina moschata (Linnaeus, 1758) (Aves: Anseriformes: Anatidae), from the area de conservacion Guanacaste, Costa Rica.

A new species of Parahadjelia occurs in the muscovy duck, Cairina moschata (Linnaeus, 1758), from the Area de Conservacion Guanacaste, Costa Rica. The new species differs from Parhadjelia neglecta Lent and Freitas, 1939, in the body size, in the spicules shape and ratio of spicules, and in having 2 pairs of sessile papillae near the tail tip of the male. The characters exhibited by P. neglecta and the new species validate its generic status distinct from Hadjelia.