Hysterothylacium rhamdiae sp.n., (Ascaridoidea: Anisakidae) from a Neotropical Catfish, Rhmdia sapo (Pisces: Pimelodidae)

a new species of hysterothylacium is described and figured. the nematodes were collected from the intestine of a neotropical catfish, rhamdia sapo, collected from its southernmost locality (napostá stream and sauce grande river, buenos aires province). the specimens resemble h. murrayense but differ in having a shorter spicules, in the number and distribution of papillae and the relative size of intestinal caecum ventricular appendix.