The sighting of some teeth jutting out of a small piece of rock in rural Queensland 30 years ago has led to the discovery of a new species of marsupial lion.
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In the ensuing decades, more fossilised remains of the animal were found by scientists in the remote north-west of the state.
Named Wakaleo schouteni in honour of paleoartist Peter Schouten, scientists believe the animal was about the size of a border collie.
The lead author of the findings, University of New South Wales palaeontologist Dr Anna Gillespie, said that judging from the predator's remains, which included its skull, teeth and upper arm bone, it would have had a stout forearm and likely lived in Australia’s rainforests about 18 million to 26 million years ago.
"The little guys would be cute except I wouldn't want to put my finger in their mouth," Dr Gillespie said.
"Even with my animal the little tooth blade's around about a centimetre long, its enough to make a nice incision."
The first discovery of Wakaleo's fossils was made in the 1980s in the Riversleigh World Heritage Area in north-western Queensland.
"A keen-eyed volunteer was scrambling along a steep track and spotted some teeth that had weathered out on a small piece of rock and this rock was taken back to the lab and processed and the limestone dissolved and this produced a palate," Dr Gillespie said.
"It was just two tooth rows of this animal and we knew at that stage it was a different Wakaleo.
"And over the years we have collected more specimens, fragments of its skull and jaw and we even managed to recover the skull from a completely different site but, like a lot of fossils, it takes a long time to get all the information together that you need and then get it written down and convert it into a scientific paper, which is what we have now.
"This is quite the norm in paleontology," she said, adding that a marsupial lion first discovered in the 1960s was not formally published until 1984.
"Sometimes it might take a year to extract the fossil out of the limestone," she said.
Weighing 23 kilograms, the animal's diet possibly included vegetation, given its broader molars at the back of its mouth, Dr Gillespie said.
“We think it might have like its veggies every now and then but I think it still probably preferred living animals,” Dr Gillespie said.
"We reckon it probably chased small vertebrates like birds, fledglings, lizards and small mammals like small possums because there were lots of those running around the forests at Riversleigh."
Dr Gillespie said Riversleigh World Heritage Area provided ideal conditions for the preservation of fossils.
“That area consists of a huge expanse of freshwater limestone, it is a wonderful substance because it is continuously being dissolved and laid down,” she said.
“The erosion and the laying down rates will vary ... but it is a great condition for preserving bones.”
The first marsupial lion, Thylacoleo carnifex, discovered in the 1850s, was the size of a lion, the biggest of its family. Wakaleo schouteni might be the smallest of the discoveries in the species but confirmation of its existence has big implications.
"The previous oldest species was about 16 million years old ... so it has pushed the origins of this genus back into a period called the late Oligocene," Dr Gillespie said.
The findings were published in the Journal of Systematic Palaeontology.
