What are the enemies of a diprotodon?

The Diprotodon was the largest of the marsupials known in ancient Australia, so it had few predators. The now extinct marsupial lion (Thylacoleo carnifex) was believed to be a predator, given that a fossil Diprotodon bone was found near some marsupial lion teeth at a site in New South Wales, and sporting tooth marks matching those of the marsupial lion.

Since the Australian Aborigines are believed to have contributed to the extinction of the Diprotodon through hunting and through changing the ecology by their fire regimes, it could be said that they, too, were its enemies.