Tyrannobdella
Tyrannobdella is a monotypic genus of leech, of family Praobdellidae, found in South America in the upper reaches of the Amazon. This newly found genus of leech takes sustenance from the mucous membranes of the mammalian upper respiratory tract, and is known to feed upon humans. It has eight teeth. Tyrannobdella rex was discovered feeding upon the mucous membrane of a girl who had recently bathed in the upper Amazon in Peru. Genetic studies show that it is closely related to "Dinobdella ferox", a similar species found in Taiwan. Characteristics. Unlike related leeches, "Tyrannobdella rex" has a single jaw  with one row of teeth. Its eight teeth are disproportionately large, with a length of up to 0.13 mm, which inspired discoverers of the species to use a name reminiscent of "Tyrannosaurus rex". These teeth are about five times as long as those in the related genus "Limnatis"; most often one will only see six teeth of "T. rex" with a microscope as the others are subcutaneous. The closely related leech "Pintobdella chiapasensis" features a likewise reduced number of teeth, namely six per jaw, but in turn it has three jaws. Life and diet. As a juvenile, "T. rex" will  bite into the mucous membranes (mucosae) of its host and feed on their blood. In contrast to other leeches, "T. rex" does not drop off its host after feeding but can remain attached at the site of its bite for days and weeks. After a time it can reach a length of up to 7 cm. "Tyrannobdella rex" favours the mucosae of mouth, nose and throat in humans. Other leeches that also settle in mucosae have been found in noses but as well near the eyes and in the genitourinary system of mammals. Symptoms. When "Tyrannobdella rex" inhabits the nasal  cavity it can cause strong headaches. Because of its small size the leech is most often not discovered immediately. Taxonomy. The characteristical single jaw in this leech has led to the establishment of a new genus "Tyrannobdella", of which only "T. rex" is known so far. A genus with only one species is called monotypic. The finding of "Tyrannobdella rex" and genetic comparisons of its genome to other leeches that infest the mucosae of mammals has brought new insight to their taxonomy. "T. rex" was put into the family Praobdellidae, which also includes the genera "Praobdella", "Pintobdella", "Myxobdella", "Dinobdella", "Limnatis , and Limnobdella". Most of these are found in Africa and Asia, "Tyrannobdella rex" being the only one from South America. Its closest relative, "Pintobdella chiapasensis", is native to Mexico, where it infests tapirs. The sister group to Praobdellidae is made up of the two South American families Semiscolescidae (genera "Semiscolex" and "Patagoniobdella") and Macrobdellidae (genera "Macrobdella", "Philobdella" and "Oxyptychus").