The continent boasts the largest fossil marsupial, Diprotodon, and a collection of the fossilized remains of animals that never appeared anywhere else on earth -- including Palorchestes, a marsupial lion called Thylacoleo carnifex, a carnivorous kangaroo called Propelopus, an assortment of dinosaurs and a recently identified order of mammals called Thingodonta, which are entirely unlike anything found on the rest of the planet.