24-16 million years ago, late Oligocene - early Miocene.
The Riversleigh Forest Beast was about the size of a sheep. It browsed on leaves, stems and other soft parts of rainforest plants.
The Riversleigh Forest Beast is related to Diprotodon, which was the largest marsupial ever. It is in the group of marsupials known as diprotodontoids, which are now extinct. Their closest living relatives are wombats and Koalas. The Riversleigh Forest Beast is one of the smallest and rarest diprotodontoids discovered so far.
The Riversleigh Forest Beast is known from two fossil skulls found close together at Riversleigh in north-western Queensland. One of the skulls belonged to an adult animal and the other to a baby. The baby would have been in its mother's pouch when it died.
Did you know?
Skulls of the Riversleigh Forest Beast have become famous as the Riversleigh 'Madonna and Child', because they appear to be the skulls of a mother Forest Beast and her baby.