Your Daily Fossil

Thylacoleo - The marsupial lion 

Mounted skeleton located in the Victoria Fossil Cave, Naracoorte Caves National Park, South Australia

Close up reconstruction by Jeanette Muirhead.

Reconstruction of Thylacoleo hunting short faced Kangaroos by Mauricio Anton. 

When: Pleistocene (2 million to 46,000 years ago) 

Where: Australia

What: Thylacoleo is another example of an extinct australian megafauna. It was the largest marsupial predator Australia has ever seen, weighing in at 250 lbs (~115kg) on average, with individuals half again as big occurring with some regularity. The common name of ‘Marsupial Lion’ comes from its large size, shortened face, and retractable claws - the latter making it unique among marsupials. The forearms of this predator were very robust and had a semi-opposable thumbs, allowing them to drag down their prey. This interpretation is supported by the morphology of the hindlimbs and pelvis, which suggests Thylacoleo habitually reared up on its haunches. It had a formidable set of teeth as well, the extremely large sets of shearing teeth gave it the most powerful bite force of any known mammal. A find of eight skeletons in a cave in southern Australia suggests these animals lived in packs. 

Thylacoleo is in the clade Diprotodontia, which contains living koalas, kangaroos, and wombats, but is not closely related to any of these forms. Rather it is in the totally extinct subclade Thylacoleonidae; all the members of this clade were carnivorous, but some were only as small as a house-cat. Like many other large endemic australian mammals, Thylacoleo vanished just under 50,000 years ago. It is thought some aboriginal cave art depicts this lost predator. The genus was named based on material shipped back to the English scientist Sir Richard Owen in the mid 1800s.