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. This species is distinguished from its congeners all over de world by possessing six pores distinctly surrounding the mouth aperture, a buccal capsule with 3-4 spiral thickenings complete, females possessing a lateral cuticular ornamentation along the body, and two pairs of preanal and three pairs of postanal papillae in males. The findings represent new hosts and geographical records.

New species of Raphidascaris (Sprentascaris) (Nematoda: Anisakidae) in Rineloricaria steinbachi (Actinopterygii: Loricariidae) from Northwest Argentina.

During a parasitological survey, we reported specimens of a new species of Raphidascaris (Sprentascaris) in Rineloricaria steinbachi from La Caldera River, province of Salta, Northwest Argentina. The new species, R. (S.) saltaensis sp. nov., is characterized by possessing 16 pairs of preanal papillae, lips with lateral protrusions and membranous elevations, and mature eggs rough-shelled with striations. This is the sixth species of the genus described in the Neotropical Region, and the second from Argentina. Rineloricaria steinbachi is reported as host of this nematode genus for the first time. A key to the species of Raphidascaris (Sprentascaris) in the Neotropical realm is provided. Also, zoogeographical and host information of the species, belonging to the subgenus Sprentascaris, is summarized.