Thylacoleo carnifex

Collection Highlights | Updated 2 years ago

Careful excavation of a Nullarbor Thylacoleo in the hope of finding fossilised DNA
Careful excavation of a Nullarbor Thylacoleo in the hope of finding fossilised DNA
Photo by Clay Bryce, image copyright WA Museum

About 46,000 years ago, most of Australia’s ‘megafauna’ (a term applied to land living animals weighing more than about 45 kg) went extinct. During glacial periods (‘ice-age’ periods,) of the Pleistocene epoch (2.6 million – 11,700 years ago), many mammal species increased in size as an adaptation to a colder climate. Australia’s ice-age megafauna included, among others, the rhinoceros-sized diprotodontids, giant flightless birds, giant snakes, enormous monitor lizards, wallabies exceeding the size of the modern red kangaroo, and wombats weighing several hundred kilograms.

Our largest carnivore was the marsupial lion, Thylacoleo carnifex. This extinct species has a most unusual background in that it actually evolved from a plant eating species of wombat or possum-type. Its dentition (teeth formations) was unlike that of any other mammalian carnivore. In dogs and cats, the canines are greatly enlarged and constitute the main killing tools. Thylacoleo, on the other hand, had no canines in the lower jaw and only small, non-functional canines in the upper jaw. The inner incisors (front teeth), however, were enormous, resembling the incisors of a rodent but on a much larger scale. The molars (back teeth, usually used for grinding plant material) and all but one of the premolars were very small. The third premolar however had evolved into an enormous bolt-cutting-like device, enabling Thylacoleo to slice through flesh with ease.

In size, an adult Thylacoleo would have been about as large as a jaguar. Thylacoleo had a very broad head and immensely powerful jaws. The bite force of Thylacoleo has been estimated to be comparable to that of the considerably larger male African lion. Remains of Thylacoleo have been found in all states of Australia but until 2002 no complete skeletons had ever been found.

In May 2002 a group of speleologist (people who explore caves), using an ultra-light aircraft, spotted cave openings in a remote part of the Nullarbor Plain. When they subsequently entered the caves they discovered numerous skeletons of extinct megafauna species, including one complete and a dozen incomplete skeletons of Thylacoleo.

Fossil Collection