Three new ancestors join the history of the Tasmanian tiger

September 10 () –

Three new species of ancestors of the Tasmanian tiger, the last specimen of which died 88 years ago in a zoo, have been discovered in fossils unearthed in northern Australia.

UNSW Sydney scientists have discovered three new species of thylacines in fossils unearthed in the Riversleigh World Heritage Area on Waanyi Country in north-west Queensland.

In a research published in the Journal of Vertebrate Paleontologypaleontologists say the new species are now the oldest members of the thylacine family to date, with an estimated age of between 25 and 23 million yearsmaking them a late Oligocene species.

The largest of these new species, Badjcinus timfaulkneri, weighed between 7 and 11 kilograms, roughly the same size as a large Tasmanian devil. This thylacine, named after Australian Reptile Park director and co-owner and Aussie Ark CEO Tim Faulkner, adds a new piece to the puzzle of the Tasmanian tiger’s ancestry, said study lead author and PhD student Tim Churchill.

“Like Tasmanian devils, the jaw of Badjcinus timfaulkneri could easily crush the bones and teeth of its prey,” he says. in a statement.

“But until now, the much smaller Badjcinus turnbulli, weighing around 2.7 kg, was the only other thylacine known from the late Oligocene. The teeth, including the lower jaw and the isolated first molar, were found at the Hiatus site at Riversleigh, which is even older than the White Hunter site where Badjcinus turnbulli was previously found. This makes Badjcinus timfaulkneri the oldest undisputed thylacine yet discovered.”

The second new member to join the thylacine family, Nimbacinus peterbridgei, It was slightly larger than a tiger cat.weighing around 3.7 kilograms. This species was described from a nearly complete jaw from the White Hunter site at Riversleigh, which is also from the late Oligocene (25–23 million years ago).

“Nimbacinus peterbridgei was a more generalized predator that probably targeted small mammals and other prey species that lived in the ancient forests of Riversleigh,” says co-author Professor Mike Archer.

“We think it may have been in direct lineage to the only other Nimbacinus species, the larger Nimbacinus dicksoni (5-7 kilograms) found in 15 million-year-old deposits at Riversleigh. This group of thylacines appears to be the one that led directly to the Thylacinus species.

“The other two new species described here appear to represent distinctive side branches in the increasingly complex thylacine family tree. This means that Nimbacinus peterbridgei It is probably the oldest known direct ancestor of the Tasmanian tiger.”

Nimbacinus peterbridgei is named after geologist, caver, author and bibliophile Peter Bridge, who has long supported palaeontological research at the University of New South Wales.

The third new member to join the thylacine family is Ngamalacinus nigelmarveni. It weighed around 5.1 kilograms, roughly the size of a red fox. It also came from the White Hunter site in Riversleigh.

“It was a highly carnivorous thylacine,” says co-author Sue Hand. “We know this because the cutting blades on its lower molars are elongated with deep, V-shaped, carnivorous (or ‘meat-cutting’) notches. Ngamalacinus nigelmarveni had these notches better developed than any of the other similarly sized thylacinids.”

Ngamalacinus nigelmarveni is named after Nigel Marven, a well-known British television presenter known for his captivating documentaries exploring the natural world and prehistoric life.

Churchill says the presence of three distinct lineages of specialized thylacinids during the late Oligocene highlights how quickly this group of marsupials diversified after first appearing in the fossil record.

“These new species exhibit very different dental adaptations, suggesting that there were several unique carnivorous forest niches available during this period,” he says. “All but one of these lineages, the one leading to the modern thylacine, became extinct 8 million years ago. That lineage ended with the death of Benjamin, the last Tasmanian tiger at Hobart’s Beaumaris Zoo, on 7 September 1936.”

Professor Archer says the idea, once suggested, that Australia was dominated by reptilian carnivores during this 25 million year interval is being steadily dismantled as the fossil record of marsupial carnivores, such as these new thylacinids, grows with each new discovery.