Who was Thylacoleo carnifex?
In present times, a large part of central Australia is a harsh desert, boiling hot by day in summer, below freezing at night. No water, deserts of stony flint, dry salt-lakes and sand dunes. Around the coasts and the eastern, southern and south-western regions the climate is generally amenable. There forests grow and native animals prosper.
Thirty thousand years ago, however, the continent wasn't like that. Rainfall was high, temperatures were mild, the land was verdant. There were extensive grasslands and game was plentiful. Proponents of an Australian aboriginal version of "first nation" ideology hold that this was the aboriginal "dream time".
However, genetic evidence now shows that the modern aboriginal people of Australia arrived here during the mid-Holocene and derive from Dravidian peoples of southern India and Pakistan. They are are thus comparatively recent settlers, like nearly all populations of the modern world.
In the far off days of the late Pleistocene Australia, like Africa today, had its own megafauna. But ours were marsupials, as distinct from the placental mammals of the Old and New Worlds. Nevertheless, the view across Australian plains would have looked remarkably like the famous Serengeti today, only with different actors.
But then, between 25,000 and 18,000 years ago, the climate changed. As the ice age neared its climax, mile high ice sheets scoured northern Europe and North America down to bedrock. Sea levels fell by 200 metres, right to the edge of the continental shelf. In the southern hemisphere, the climate cooled, rainfall diminished. The Australian continent suffered cold and extreme aridification the climate rapidly changed. The deserts moved coastwards and dunes dominated the landscape of western Victoria. Rivers dried out out and springs that had watered lush grasslands were left as oases in a barren desert.
If it is true that aboriginal folklore speaks obliguely of the megafauna, then it may be that such references originate from a time much closer to the present than the Last Glacial Maximum. Is it possible that some megafauna did survive the cataclismic events of the terminal Pleistocene into more recent times?
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At Lancefield Swamp, megafauna that were drawn to perhaps the last remaining waterhole in the district became mired and perished, leaving their bones to be found by latter day palaeontologists. The great dying in Sahul, as prehistoric Australia is known, appears to have coincided with the dramatic desiccation that occurred at the height of the Ice Age. When the ice at last relented, 10,000 years ago, the megafauna of Australia were almost all extinct.
Animals who survived the Quaternary extinction event generally reduced in size compared with their Pleistocene forebears. Consequently, Australian marsupial fauna today is but a pale shadow of what it once was.
Evolution in Australia spawned equivalent marsupials to fill the same ecological niches that were available elsewhere to placental mammals. Where there were no herds of fast moving zebras or antelopes, there appeared kangaroos. Where there were no large grazers like rhinos and elephants, there arose Diprotodontines and Zygomaturines. And where there were no lions or leopards, there appeared marsupial predators.
Most notable among these was Thylacoleo carnifex, the Australian "Marsupial Lion". It was a large animal, ranging up to the size of an African lion. Its possible cat-like appearance may owe something to the theory that T. carnifex was descended from the Burryamids, or Pygmy Possums, which are native to the mountains of S.E. Australia. Hence an arboreal reconstruction with leopard-like appearance is presented.
An alternative interpretation has thylacoleonids arising from Vombatid stock. In this case they would have been more closely related to modern day wombats than to possums. That ancestry would, presumably, leave them looking not quite so feline in appearance. The reader should consult the reference material for further exposition on the question of Thylacoleo's ancestry.
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The dentition of this animal was unique. It had no canine teeth as do placental predators like wolves or lions. Instead it was equipped with very large incisors and extremely specialised carnassial teeth. These had become blade-like cutting edges, two pairs only being positioned on the upper and lower jaws. It has been asserted that T. carnifex's dentition represents the most extreme specialisation of any known mammalian carnivore.
The reader is directed particularly to references #2 & #3 for a detailed discussion.The front paws of T. carnifex were equipped with a partly opposable thumb. The terminal phalanx of the thumb sported an impressively large, curved claw, while the other digits had smaller claws. The rear feet were equipped with similarly opposable thumbs. It's probably true to say that this was an animal equipped with four hands, rather than paws, and that it almost certainly was primarily an arboreal hunter. However, fossil specimens have been unearthed in areas which were open plains when the animal lived. So it appears to have been resourceful enough to make a living with or without a forest habitat.
Variation in the size of fossil remains are usually interpreted to mean that males of the species were bigger than females. Sexual dimorphism is common in many mammalian species, for instance kangaroos, lions and seals. It generally indicates a breeding system where males must defeat and dispossess other more dominant males for access to females. In such species, mature males are often fewer in number than breeding-age females.
Generally speaking, fossil T. carnifex presents as a large animal which exhibited a wide range in body size. Fossil evidence suggests that an individuals could have weighed uo to about 160kg. The largest specimens, which were about the size of an African lion, Panthera leo, appear to have lived in south-eastern Australia.
If Thylacoleo carnifex was cat-like in appearance, this may have been an example of convergent evolution. The most outstanding case of this phenomenon is the Thylacine, the famous marsupial wolf. It's an animal which bears an astonishing physical resemblance to placental wolves. Yet, as a marsupial, it's about as far removed from them as a gazelle is from a kangaroo.
One of the many oddities thrown up by Darwinian Selection in Australia is that examples of convergent evolution appear to be restricted to carnivorous animals. For obscure reasons, Australian herbivores don't seem to exhibit the phenomenon. For those who may wish to view an assembled skeleton of Thylacoleo carnifex, there are exhibits at the Naracoorte Caves, the fossil site in South Australia.
T. carnifex disappears from the fossil record about 30,000(?) years ago. Are there any representations of Thylacoleo available in prehistoric rock art from so long ago? Surprisingly, the answer is a tentative 'yes'.
This image is taken from The Dreamtime Animals: extinct megafauna in Arnhem Land rock art, P.Murray & G. Chaloupka, Archaeol. Oceania 19 (1984) 105-116. The authors cautiously rate it a possible image of Thylacoleo.
Want to know more? Better check out what Australia's foremost expert, Steve Wroe, has to say about Thylacoleo.
Want to see realistic models and images of Thylacoleo? check out Jeff Johnson's representations of Thylacoleo, Australia's super-predator from the Pleistocene era.
Thylacoleo Remembrance - best Thylacoleo resource on the web!
The Thylacine Museum - the most comprehensive resource available about Australia's famous marsupial carnivore.
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