Gastrointestinal nematodes of freshwater fish from Pilcomayo River, Argentina, including description of a new species of Procamallanus (Spirocamallanus).

Helminthological examination of viscera of six freshwater fish species, collected from Misión la Paz, Pilcomayo River, Province of Salta, Argentina, revealed the presence of five species of parasitic nematodes belonging to the Camallanidae, Cystidicolidae, Cucullanidae and Anisakidae  The material also contained one unknown species, Procamallanus (Spirocamallanus) tomsici sp. nov. collected from Pimelodus albicans, Pygocentrus nattereri and Hoplias misionera.