This is Tyrannobdella rex, a newly-discovered leech species named for its terrifying, human-looking teeth. And now scientists know more about why it wants nothing more than to swim up your nose or into your mouth.


Most people are familiar with the type of leech which sticks on your skin and sucks out your blood. A thousand action movies and TV shows have taught us they dislike heat, so I'm sure we all have a MacGuyver plan for if we ever get attacked by blood suckers.

But what about the ones that feed on mucosa, AKA snot and spit? The leeches that will swim up your mouth or nose, and live there for weeks at a time, siphoning nutrients from your gooey bits? It turns out there are dozens of species which prefer to feast on you from inside your orifaces.


Let me introduce Tyrannobdella rex, named for its single large jaw, with eight oversized teeth. Found in Perú, it was discovered up the nose of a nine-year old girl, who bathed in streams and lakes. She complained of a "sliding" feeling in her nose, and they spotted a 65mm leech lodged up her nostril, which took some effort to dislodge. After this new species was named, two older specimens were found - one 25mm and the other 60mm, also found up people's noses in Perú. At least the slithery bastard is kind enough to not cause pain while it's eating.

T. rex is related to a number of other species of leech, which are more than happy to go beyond just the nasal cavity, and can be found "infesting various body orifices such as the eyes, urethra, vagina, or rectum". That picture just above? That's Dinobdella ferox, found in India and Taiwan, but a close relative to T. rex according to DNA testing.


But T. rex is unique, as it's the only species identified with single jaw, armed with such large teeth. The scientists responsible for this leech's classification said:

No other leech species is known to have but a single armed jaw with such large teeth. The reduced number of teeth, a caudal sucker wider than the posterior of the body, and preference for feeding on mucous membranes of mammals all indicate the placement of this new taxon within the family Praobdellidae among the genera Praobdella, Myxobdella, Dinobdella, Limnatis, and Limnobdella. Pintobdella chiapasensis similarly has few (six) teeth per jaw, albeit for each of three jaws. Tyrannobdella rex n.sp. unique in possessing only one jaw with eight large teeth (e.g., five times the height of those in the genus Limnatis).


So next time you feel something slippery in your nose, is it an oncoming cold? Or something far more creepy?

via Public Library of Science. All images also from there.

BONUS GROSSOUT: Want to see a similar leech in action? This video by Alejandro Oceguera shows a leech related to Tyrannobdella rex, another mucosal species known as Pintobdella chiapasensis, found at Lagunas de Montebello in Chiapas, Mexico.