Paracamallanus amazonensis sp. n. (Nematoda: Camallanidae), a parasite of the catfish, Hypophthalmus edentatus (Pisces: Hypophthalmidae), of the Brazilian Amazon.
Paracamallanus amazonensis sp. nov. is described and figured from the intestine of a fish called "mapará", H. edentatus from Marchantaria Island, Solimões River, Amazonas State, Brazil. Of the 6 species described in the genus, P. amazonensis sp. nov. resembles only P. cyathopharynx in having a buccal cavity divided into 2 parts posterior to the valves. The new species differs from P. cyathopharynx in having: a buccal cavity without teeth; 6 pairs of precloacal papillae and a single spicule in the male; a vulva with the posterior lip in the form of a fold which projects anteriorly; a pointed tail in the female. This is the first report of a genus of Paracamallanus in South America.