A newly discovered species of three-foot-long (one-meter-long) platypus, dubbed Obdurodon tharalkooschild, swam through freshwater pools in Australian forests about 5 to 15 million years ago, according to a new study. That's a much bigger critter than a modern-day platypus, which at 15 inches (38 centimeters) long is about the size of a small domestic cat.

Scientists fleshed out the animal based on a single tooth found several years ago in limestone collected from the fossil-rich Riversleigh World Heritage Area of northwest Queensland (map).

The limestone fossils were stowed in a cupboard and forgotten until study leader Rebecca Pian, a Ph.D. student at Columbia University in New York City, pulled them out in 2012 while studying at Australia's