First-ever look at complete skeleton of Thylacoleo, Australia's extinct 'marsupial lion'

[Dubious]

December 12, 2018, Public Library of Science
Thylacoleo carnifex reconstructions.

Thylacoleo carnifex reconstructions.
(A) Reconstruction of the skeleton of T. carnifex. (B) Body outline based on examination of musculature evident in x-ray imaging of marsupials Vogelnest and Allen. Credit: Wells et al., 2018

Thyalacoleo carnifex, the "marsupial lion" of Pleistocene Australia, was an adept hunter that got around with the help of a strong tail, according to a study released December 12, 2018 in the open-access journal PLOS ONE by Roderick T. Wells of Flinders University and Aaron B. Camens of the South Australia Museum, Adelaide. These insights come after newly-discovered remains, including one nearly complete fossil specimen, allowed these researchers to reconstruct this animal's entire skeleton for the first time.

A marsupial predator with an estimated weight of over 100kg, Thylacoleo was unlike any living animal, and paleontologists have long tried to interpret its lifestyle from incomplete remains. The new fossils, discovered in Komatsu Cave in Naracoorte and Flight Star Cave in the Nullarbor Plain, include the first known remains of the tail and collarbone of this animal. The authors used this new information to re-assess the biomechanics of Thylacoleo, and by comparing its anatomy to living marsupials, reach new conclusions about the biology and behavior of the "marsupial lion".

The tail of Thylacoleo appears to have been stiff and heavily-muscled, probably allowing it to be used along with the hind limbs as a "tripod" to brace the body while freeing up the forelimbs for handling food or climbing, as many living marsupials do. The analysis suggests that Thylacoleo had a rigid lower back and powerful forelimbs anchored by strong collarbones, likely making it poorly suited for chasing prey, but well-adapted for ambush hunting and/or scavenging. These features also add to a list of evidence that Thylacoleo was an adept climber, perhaps of trees or steep-walled caverns. Among living marsupials, the anatomy of Thylacoleo appears most similar to the Tasmanian devil, a small carnivore that exhibits many of these inferred behaviors.

The authors add: "The extinct marsupial lion, Thylacoleo carnifex has intrigued scientists since it was first described in 1859 from skull and jaw fragments collected at Lake Colongulac in Victoria Australia and sent to Sir Richard Owen at the British Museum. Although Australia's largest marsupial carnivore it retains many features indicative of its diprotodont herbivore ancestry and its niche has been a matter of considerable debate for more than 150yrs. Recent cave finds have for the first time enabled a description and reconstruction of the complete skeleton including the hitherto unrecognised tail and clavicles. In this study, Wells and Camens compare the Thylacoleo skeleton with those of range of extant Australian arboreal and terrestrial marsupials in which behaviour and locomotion is well documented. They conclude that the nearest structural and functional analogue to Thylacoleo is to be found in the unrelated and much smaller Tasmanian Devil, Sarcophilus harrisii, a scavenger /hunter. They draw attention to the prevalence of all age classes within individual cave deposits as suggestive of a high degree of sociality. Those ancestral features Thylacoleo shares with arboreal forms are equally well suited to climbing or grasping a prey. They conclude that Thylacoleo is a scavenger, ambush predator of large prey."

More information: Wells RT, Camens AB (2018) New skeletal material sheds light on the palaeobiology of the Pleistocene marsupial carnivore, Thylacoleo carnifex. PLoS ONE 13(12): e0208020. doi.org/10.1371/journal.pone.0208020


Read more at: https://phys.org/news/2018-12-first-ever-skeleton-thylacoleo-australia-extinct.html#jCp

 

[Dubious]

Cave diver finds pre-historic bones in 'new room' of underwater cave network
ABC South East SA
By Selina Green
Posted 30 minutes ago

PHOTO: Palaeontologists say the bones belong to several extinct species, including the marsupial lion. (Supplied: Flinders University)

A cave diver has uncovered a globally significant collection of ancient bones from Australia' pre-historic period in the dark depths of South Australia's underwater caves.

The chance discovery was made in Mount Gambier's longest and largest cave system, having been hidden from human eyes for thousands of years.

The jaw bones and teeth from extinct mega-fauna were in a chamber about 1 kilometre from the entrance to Tank Cave, located on private property.

Local cave diver Ryan Kaczkowski said he was exploring the cave system when he found the "new room" containing the bones.

"It's a large collection of bones and they're strewn about the place, so I was able to document them and take photos and get some sizing," Mr Kaczkowski said.

He sent the images and details to palaeontologists and was told the bones belonged to several extinct species, including the short-faced kangaroo and the marsupial lion.




Mr Kaczkowski said it was not unusual to find bones near cave entrances, but it was rare to come across them this deep into a cave system.

"What it means is that it would have been an entrance — some kind of pit or collapse a long, long time ago and it was open so land animals could maybe live in it, or fall into it and at some point it was closed over a long time ago, so it's contained and preserved what's fallen in," he said.

"The room itself has obviously never been entered by anyone or anything, so suddenly to get into that and see that is quite a special experience."

He said he was careful not to disturb the bones, and instead surveyed their location and took measurements.

PHOTO: Cave diver Ryan Kaczkowski was exploring Mount Gambier's longest and largest cave system when he found the bones. (ABC South East SA: Glen Moret)


Palaeontologist 'envious' of discovery
It's this approach that has drawn the praise of fellow cave diver and palaeontologist Dr Julien Louys from Griffiths University.

"It's best to leave them in place so professionals can assess and work out the best way to extract those fossils, so we don't lose any scientific information," Dr Louys said.

"In any system whatsoever, whether it's a dry cave, a wet cave or even out in the open, if you find fossils, as soon as you take them out of their context you lose a huge amount of information."

Dr Louys said this find was "particularly significant" because it contained obvious examples of extinct mega-fauna.

"Bones are relatively common in some of these flooded caves but most of the time they're quite modern, quite recent. We're talking maybe in the last few thousand years or so," Dr Louys said.

"Not just for Australia but all around the world it's quite rare to find such old material in these flood caves."


There have been many discoveries of Thylacoleo fossils in the south east region of SA. (Supplied: Steven Bourne)


He said such ancient fossils were usually "cemented" into the floors and walls of dry caves, making it more challenging to extract them. They are also more prone to being destroyed and weathered away over time.

"Ryan is just incredibly privileged [because] he's probably the first person in the last few hundred thousand years who's actually laid eyes on these fossils. I'm more than just a little bit envious," he said

Discovery unlikely to be the last
One of the species identified amongst the fossils — the marsupial lion (Thylacoleo carnifex) — was the largest carnivorous Australian mammal in the Pleistocene epoch.

An ambush predator, the animal's enormous scissor-like teeth, used in conjunction with a large thumb claw, meant it would be able to dispatch much larger prey quite easily.

University of Adelaide palaeontologist Dr Liz Reed, who is based at the world heritage listed Naracoorte Caves, said there had been many discoveries of these types of fossils in the south east of South Australia.

"I often joke that the Naracoorte Caves in the world headquarters for the Thylacoleo — we've found more [here] than anywhere else," Dr Reed said.


The marsupial lion (Thylacoleo carnifex) was the largest carnivorous Australian mammal in the Pleistocene epoch.(Wikicommons: Nobu Tamura)


Mr Ryan Kaczkowski is excited to put on his wetsuit again and return to the site of his amazing discovery.

The Cave Diving Association of Australia is working on a grant to potentially excavate and preserve the site.

"I dive it every week so 100 per cent I'll be back with my suit on and back out there as soon as you know it," he said.

"There's always the possibility of more and that's part of the drawcard of the sport I suppose. There's literally hundreds of dive sites that we know about here that we're waiting to explore.

"It's going to be an ongoing discovery."

https://www.abc.net.au/news/2018-12-13/cavediver-finds-large-fauna-bones-south-australia/10599218