Ornithostrongylus cristatus sp n. (Nematoda, Trichostrongylina, Molineoidea), a parasite of Columbigallina talpacoti (Temm., 1811) (Aves, Columbia) from Paraguay.

The new species is closely related to O. travassosi described by Maplestone in 1932 from Chalcophas indica from India, to O. minutus and to O. ihering i, described by Travassos in 1941, from Brazil (Esto do Grosso), all three from Columbidae. O. travassosi is differentiated by rays 3 very far from ra ys 4, by rays 9 and 10 merged together and by the different shape of the gu bernaculum. O. Minutus is distinguished by the absence of cuticular ala and by the absence of a common trunk between rays 5 and 6 (caudal pattern of t ype 2-2-1). O. iheringi differs by the length of the females, twice longer, and different shape of the gubernaculum. In addition, O, cristatus sp. n. is characterized by the presence of small crests on the interno-dorsal bran ches of the spicules. In one Columbigallina, Ornithostrongylus cristatus was present with four fe males belonging to the Pudicinae, more particularly to the genera Heligmost rongylus or Fuellebornema. A more precise identification is impossible with out the examination of males. The Pudicinae are parasites of Caviomorpha an d cricetid rodents and Neotropical sciurids. The occurrence of Pudicinae in a bird is discussed.