Obdurodon tharalkooschild

Obdurodon tharalkooschild is an extinct species of platypus in the genus "Obdurodon". Only one single tooth has been found. This was at the Miocene fossil beds in Riversleigh in Queensland, Australia.
The tooth was discovered in 2012 by a team from the University of New South Wales including Mike Archer, Suzanne Hand, and Rebecca Pian. 
The species lived during in the middle and upper Miocene about 5–15 million years ago. Wear on the tooth shows that it probably crushed hard shells such as those of turtles. Because of this, scientists believe that "O. tharalkooschild" was carnivorous. They also believe that it was twice the size of the modern platypus at one metre long. Its name was chosen in honour of an indigenous Australian creation story for the platypus, where a duck named Tharalkoo gives birth to a strange and fantastic creature after being ravished by a water-rat.