Marsupial Lion

The Marsupial Lion (Thylacoleo carnifex; or meat cutting-marsupial-lion; or pouch-lion-butcher) was a large, carnivorous marsupial mammal that lived in Australia from the early to late Pleistocene Era (1,600,000–46,000 years ago). Despite its name, it wasn't part of the cat family, but was more closely related to wombats. It was one of the apex predators at its time, and probably fed on early man.

Anatomy
Although the marsupial lion had been first discovered in the mid 19th century, it's only been recently that we've found enough bones to make a clear visual of what it looked like. The marsupial lion was about the size of a modern day cougar, growing to be about 5-feet long from nose to tail, 2.5 feet tall at the shoulder, and weighing up to 285 lbs. In the biggest species making it the biggest mamalian predator to have ever lived in Australia. Despite its rather small size, it had a very strong biteforce. Pound for pound, it had one of the strongest bites in history. It had sharp, slicing teeth that were designed to clamp down and, literally, butcher its preys' flesh. It spent most of its time in trees, like most modern marsupials, and would lie in wait until its prey, such as a large short-faced kangaroo or an ancestor of the wombat the size of a rhino, walked by and would jump down and ambush its prey, using its huge bite to kill its victims. Another weapon it has is its thumb claw.

Environment
The marsupial lion lived in Australia, where it was mostly grassland with a few random trees. It shared its environment with its prey, with the giant short-faced kangaroo Procoptodon, the giant wombat Diprotodon, and the mega lizard Megalania, an apex predator rival, and even early man (which it probably preyed upon and rivaled for top predator).