Moennigia celinae n. sp. collected from the small intestine of Chaetophractus vellerosus and Chaetophractus villosus (Xenarthra, Dasypodidae) from Argentina is herein described. This new species belongs to the genus Moennigia because it possesses a short uterus with few eggs, atrophied distal branch of the ovejector, vulva near the anus, and a conical tail. The new species has a synlophe with 17 symmetrical ridges and slight ventro–dorsal orientation. The spicule length:body length ratio is similar to that of the other species parasitic of Dasypodidae; however, Moennigia celinae n. sp. differs from Moennigia pintoi and Moennigia lutzi because the latter lack a gubernaculum, and from Moennigia complexus, Moennigia moennigi, Moennigia filamentosus, Moennigia intrusa, Moennigia littlei, Moennigia pulchra and Moennigia dessetae by the latter having very complex spicules with 2 or 3 points at the distal extremity. Moreover, Moennigia celinae n. sp. differs from Moennigia virilis by the length and shape of its spicules. Moennigia celinae n. sp. can be distinguished from Moennigia travassosi by the shape of the dorsal ray of the caudal bursa. Moennigia celinae n. sp. resembles Moennigia pseudopulchra but the gubernaculum of the latter is V-shaped. This is the second report of a species of Moennigia in Argentina and the first for the genus Chaetophractus.