Alternative Pleistocene question - Where were the marsupial super-carnivores?

 Hello again,

Now for a post that has a relatively unusual theme. I am seeing speculative-evolution posts recently that propose an alternate Pleistocene, in regards to Neogene mammal evolution. This led me to an Australian Palaeontology question that has been brought up in journals a few times, where were all the marsupial super-predators?

The largest Ice Age marsupial predators in Australia numbered only 3, the Thylacine, the Thylacoleo, and the Mainland Devil, all of these were probably below 100 kilograms in weight. Mammal Palaeontologists in Australia have occasionally wondered why we see no "marsupial cheetah" or "marsupial bear" or even any larger marsupial predators closer in size and ferocity to a tiger or Amphicyonid.

It appears the question comes down to the old Australian question of reptillian supremacy (no, not David Icke), there were giant Varanids like Meagalnia and even Komodo Dragons, as well as fair-sized terrestrial Crocodiles like Quinkana and others. Such stiff competition towards marsupial carnivores may have levelled the playing field.

So today, I present a late Pleistocene where we do actually have a Marsupial super-carnivore, and a marsupial cheetah, my own designs.



Thylohemiursus is a giant Thylacoleonid predator, reaching weights close to that of the largest tigers and Amphicyonids. This creatures differs from Tylacoleo in that it *retains* crushing molars to aid it in processing bone, and that its incisors form a separate, caniniform shape, we see similar shapes in Diprotodontids like Euowenia, but not so far in our world with pouched carnivores. It has a longer body and tail, and more muscular limbs than Thylacoleo, but they serve a similar purpose, grappling large prey in place while administering a killing bite, in this case even greater in bite force than Thylacoleo itself.

The Pardomacropus is a kind of Propleopine kangaroo, which in this timeline produced true carnivores and even larger omnivores. It is a pursuit predator similar in weight to a red kangaroo, that travels in leaps and bounds in order to tackle, grapple and kill large Macropoidines such as red and grey Kangaroos. At full pelt it can approach the Macropodines in speed, and prey is dispatched with a cutting and throttling bite to the throat via stabbing incisors and slicing blade-like premolars. In convergence to theropod dinosaurs, it exhibits incipient digitigrady and digit loss.

All images, designs and writing on this blog are the property of Timothy Donald Morris, do not use, reproduce, or copy them without my permission.
© Timothy Donald Morris 2023

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