Limnognathia is a genus of microscopic acoelomate freshwater animal that was discovered in Disko Island, Greenland, in 1994. Since then, it has also been found on the Crozet Islands of Antarctica as well as in the British Isles and the Spanish Pyrenees, suggesting a worldwide distribution. There are two known species of Limnognathia: L. maerski, described in 2000, and L. desmeti, described in 2025.