2017-03-03 Fri

Limnognathia maerski, a microscopic animal, living in homeothermic springs on Disko Island, Greenland has variously been assigned as a class or phylum in a Gnathifera superphylum, named Micrognathozoa. It is related to the rotifers and gnathostomulids, grouped together as the Gnathifera. It is one of the smallest animals known with an average length of one-tenth of a millimeter.

Its jaws are very complicated having fifteen separate elements. The parts of the jaw structure are very small and are connected by ligaments and muscles. It can extend a part of its jaw structure outside of its mouth while eating. It also extends much of its jaw structure outside of its mouth when it is regurgitating items that are indigestible. Its main diet is bacteria, blue-green algae, and diatoms.

It has a large ganglion, or 'brain', on its head, and paired nerve cords extending ventrally (along with the lower side of the body) towards the tail. Stiff sensory bristles made up of one to three cilia are scattered about the body. Flexible cilia are arranged in a horseshoe-shaped area on the forehead (moves food particles towards the mouth), and in spots on the sides of the head and in two rows on the underside of the body (move the animal).

All specimens of L. maerski that have been collected have had female organs. They lay two kinds of eggs: thin-walled eggs that hatch quickly, and thick-walled eggs that are believed to be resistant to freezing, and thus capable of over-wintering and hatching in the spring. The youngest L. maerski specimens collected may also have male organs, and it is now theorized that the animals hatch as males and then become females.

Greenland issued this 10 Danish krone commemorative stamp of Limnognathia maerski on 20th June 2005.