Two new tichostrongylid nematodes of the family Viannaiidae Durette-Desset & Chabaud, 1981 coparasites in Dasyprocta fuliginosa Wagler, 1832 from the State of Amazonas, Brazil, are described: Viannella trichospicula sp. nov. is differentiated from the other species of the genus by the extreme slenderness of its spicules. Avellaria intermedia sp. nov. is distinguished from the single type species Avellaria avellari Freitas & Lent, 1934, by a smaller number of cuticular ridges (17 versus 27), a higher ratio of spicule length/ body length (8% versus 5.6%) and spicules with a single tip. This genus, synonymized with the genus Viannella Travassos, 1918, by Durette-Desset (1968) is re-established, the female being didelphic. It is the first record of a nematode of the family Viannaiidae in a host of the family Dasyproctidae Bonaparte, 1838.
Avellaria intermedia sp. nov.; Brazil; Caviomorpha; nematodes; rodents; Viannaiidae; Viannella trichospicula sp. nov
