The Wet Tropics contains several groups of animals that are relicts or early descendants of fauna that were around 60 million years ago after the dinosaurs became extinct. These include ancient lineages of frogs, geckos, legless lizards, dragons, skinks, cassowaries, scrubfowl, brush turkeys, songbirds, chowchillas, beetles, leafhoppers, cockroaches, spiders and land snails.
The Wet Tropics also contains some of the most primitive marsupials - the carnivorous dasuroids. These are thought to have evolved in rainforests about 40 million years ago and been the ancestors of Australia's dry-adapted marsupials. The musky rat-kangaroo (Hypsiprymnodon moschatus) is the most primitive kangaroo and is restricted to the Wet Tropics. It represents an early evolutionary stage of development from possum-like marsupials. The musky rat-kangaroo is the only living member of group descended from Gondwanan ancestors that retained the mobile first toe on the hind foot - a possum characteristic. Five of Australia's six ringtail possum species are in the Wet Tropics (four of them endemic) and are descended from a common ancestor.
The Wet Tropics of Queensland is the most important area for several lineages of Australo-Papuan songbirds such the bowerbirds, scrubwrens, thornbills and gerygones.
The frog genuses Taudactylus and Mixophyes are derived from Gondwanan times. Two of Australia's six species of Taudactylus are found only in the Wet Tropics. Mixophyes is represented in the Wet Tropics by Mixophyes schevilli, the northern barred frog
The Wet Tropics is also important because it contains a unique record of the mixing of Asian and Australian animals and plants when the continents collided about 15 million years ago. In some cases these plants and animals, some of common origin, had been separated for 80 million years. So some animal species of Gondwanan origin were able to take up residence in the Wet Tropics after a long absence.
You can read all the details about animal and plant evolution in the Wet Tropics in the update of the World Heritage nomination 2002.
The Wet Tropics evolutionary timeline poster [1.6MB] gives a summary of plant and animal evolution over the ages. Click on it to enlarge it.