Micrognathozoa

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. Limnognathia is the only genus in the phylum Micrognathozoa ("small-jawed animal"). DescriptionFeedingLimnognathia mainly feeds on bacteria, blue-green algae, and diatoms. It has complex jaws, with fifteen separate elements; these elements are very small, ranging from 4 μm to 14 μm. The animal can extend part of its jaw outside its mouth while eating. It also extends much of its jaw outside its mouth when it is regurgitating indigestible items. AnatomyLimnognathia has a large ganglion, or 'brain', in its head, and paired nerve cords extending along the lower side of the body towards the tail. Stiff sensory bristles made up of one to three cilia are scattered about the body. These bristles are similar to ones found on gnathostomulids, but up to three cilia may arise from a single cell i