A new cucullanid nematode, Cucullanus mexicanus sp. n., is described from specimens
recovered from the intestine of the freshwater catfish Rhamdia guatemalensis
(Günther)(Pisces, Pimelodidae) from three localities (brooks El Sal-tillo, Valle Nacional and
San Juan Bautista) in the State of Oaxaca, central Mexico. The new species, belonging to
the subgenus Cucullanus, distinctly differs from all its congeners in having an unusually
large, conspicuously elongated precloacal sucker and only one pair of preanal papillae near …