T-Rex of Leeches

Many Peruvian swimmer have had found leeches in their nose. Brandon Keim of wired.com explained the leeches as “pinkie-finger-sized bloodsuckers that have a single jaw, with teeth five times longer than those found in any other leech." They were name Tyrannobdella rex, which means tyrant leech king. The first instant of doctor finding this leech was in the nose of 6-year old boy in San Martin, Peru in 1997. The most interesting thing about these is that they share a common ancestor with the T-Rex.
The thing the interested me the most about this article was how these leeches could be related to the T-rex. They are two completely different organisms and yet they still share a common ancestor. Also the fact that in most cases the leech was found in its victim’s nose. If your swimming or whatever in the water, how can you not feel it go into your nose.