Marsupial lions, also known as thylacoleonids, are an extinct family of marsupials that were present in Australia from about 24 million years ago up until the end of the Pleistocene era, about 30,000 years ago. At present, the thylacoleonid family contains nine species, five of which belong to the genus Wakaleo.
A new species was discovered by fossil remains in 2017. Wakaleo schouteniwas the size of a Collie dog and weighed about 23 kilograms.