Two species of Synhimantus (dispharynx) railliet, Henry and Sisoff, 1912 (Nematoda: Acuarioidea: Acuariidae), in passerine birds from the Area de Conservacion Guanacaste, Costa Rica.

Members of 2 species of Synhimantus (Dispharynx) live under the lining of the gizzard in passerine birds from the Area de Conservacion Guanacaste, Costa Rica. Synhimantus (Dispharynx) nasuta (Rudolphi, 1819) occurs in Thraupis episcopus, Turdus grayi, Caryothraustes poliogaster, Platyrinchus cancrominus, Ramphocaenus melanurus, Vermivora peregrina, and Geothlypis poliocephala. A single male, in Turdus grayi, apparently representing a new species, distinguishable from all other species of Synhimantus (Dispharynx) by having similar shaped left and right spicules, is described but not named.