Platyzoa genera

Cosmognathia is a genus of worms belonging to the family Pterognathiidae.

Haplognathia is a genus of worms belonging to the family Haplognathiidae.

Neodasys is a marine and hermaphroditic genus of gastrotrichs, with a worm-shaped body and lateral adhesive tubes, in the class Chaetonotida. It is the only genus in the family Neodasyidae, which is the only family in the suborder Multitubulatina.

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.

Paucidentula is a monotypic genus of worms belonging to the monotypic family Paucidentulidae. The only species is Paucidentula anonyma.

Pterognathia is a genus of worms belonging to the family Pterognathiidae.

Rastrognathia is a monotypic genus of worms belonging to the monotypic family Rastrognathiidae. The only species is Rastrognathia macrostoma.

Rhomballichthys is a genus of gastrotrichs belonging to the family Chaetonotidae.

Problognathia is a monotypic genus of worms belonging to the monotypic family Problognathiidae. The only species is Problognathia minima, also known as the problematic jaw worm.