Wednesday, May 13, 2009

Cool

As you know, where science is concerned it takes quite a lot to get me excited, even when it related to paleontology. But this paper by Akerman & Willing, which was published in the March edition of the journal Antiquity, is very, very cool. It seems like Willing may have discovered the first authenticated cave painting of Thlacoleo carnifex, the marsupial lion.

The name is a misnomer. Thylacoleo ("pouch lion") was actually a possum the size of a leopard. It lived in Australia during the Pleistocene; it is fairly well-known from fossils, and the last ones seem to have gone extinct around 30,000 years ago. Since the ancestors of the Australian aborigines arrived in Australia about 50,000 years ago, they would have been more than familiar with it. Probably more familiar than they wanted.

Now you may be thinking, "big possum, huh? What's so scary about that?" Well, listen to one who did his PhD on possums - even the modern ones, which are about the size of a cat are scary animals. I once worked on a project in a Papua New Guinea where we fitted radio telemetry collars to possums. It took two of us to do this, wearing heavy duty gauntlets; one to fit the collar and the other to restrain the angry, snarling possum. "Restrain" in this case meant putting your whole weight on the thing's body to pin it to the ground. Even so, they sometimes got loose - under the wooly fur, they were solid muscle. And this was an animal that weighed maybe 5lbs and ate fruit. Now imagine tackling something with the same basic anatomy, but weighing 300lbs and eating meet. Nightime in the Outback 40,000 years ago can't have been much fun.

The first artists often drew pictures of the megafauna on which they lived, or which lived on them. From the caves of Europe we have richly painted bestiaries of horses, deer, bison, mammoths, lions, ibex and a host of other big Pleistocene mammals. Sometimes these are stylized, but often they are remarkably lifelike and consistent in appearance across different sites, such that we can use them to reconstruct the appearance of long extinct animals - the fact that the Steppe bison (Bison priscus) had a reddish body and black fur on its face and hump, that the giant deer (Megaloceros giganteus) had a brownish back, creamy chest, and dark markings around the neck and shoulders, or that Pleistocene lions in Europe were mostly maneless.

By contrast, despite the number of aboriginal petroglyphs that are known from Australia, paintings of the continent's extinct fauna have proved frustratingly elusive. Pleistocene Australia sported an impressive range of odd animals, including giant short-faced kangaroos, rhino-sized herbivores, 10 foot tall flightless birds, and a 20 foot-long relative of the Komodo dragon. However, prior to the Thylacoleo discovery the only contemporary representation of the Australian megafauna known was an animal in rock art from the Kakadu national park which has been indentified as the "marsupial tapir," Palorchestes.

So the current image, which was found by Tim Willing on the wall of a rock shelter in the Kimberley region of Western Australia, is very important. It shows a large, striped animal with powerful forelimbs, a short muzzle, and pricked ears. The arrangement of the genitals shows testes in front of penis, which is typical of marsupials. The tail is long and sticks straight out from the body. There was another stripey carnivore in Australia during the Pleistocene - the thylacine (Thylacinus cynocephalus), which became extinct on the mainland about 2000 years ago but clung on in Tasmania as recently as the 1960s. However, there are also many cave paintings of thylacines and none of them look like the one that Willing discovered. So it seems this may be the real deal.

The feature that really resonated with me was the way in which the artist had emphasized the size of the forelegs. Thylacoleo had a battery of weaponry at its disposal, including huge shearing premolars like scissor blades and pairs of stabbing incisors, both upper and lower, but it is clear that the feature that most impressed the ancient aborigines were those arms. I clearly remember trying to extract angry possums from cages in New Guinea. The animals would rear up on their back feet, supporting their weight on their stiffened tails, and strike out at me with their clawed forepaws, all the while emitting a chorus of snarls and growls that sounded like a baby's cry mixed with a buzz saw. Bad enough with something cat sized, but in a 300lb animal, when all you have is a spear, it doesn't bear thinking about.

2 comments:

  1. I'm really excited about this, but I can't shake the suspicion that this is really just a Thylacine. The forelimbs do look just right, but the head shape and striping cannot be said to fall outside of possible artistic license for a thylacine. We need to find more examples of both creatures in art of that time (a luxury I know we don't have) in order to be sure.

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  2. I guess it's a bit suspicious that something completely unrelated to thylacines would also have stripes - why not spots, which are present in a number of groups of marsupials?

    I guess I just want to believe.. :)

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