In a region of outback Queensland so harsh only the dead seem to reside, palaeontologists have discovered a sprawling fossil site bursting with the bones of ancient mammals.
The remains may even include a previously unknown primitive species.
''There are some animals here I've never seen before,'' said University of NSW professor Michael Archer.
New fossil site in outback Queensland
In a region of outback Queensland 400km inland from Mount Isa, scientists have discovered a sprawling new fossil site bursting with the bones of ancient mammals.PT5M40S http://www.canberratimes.com.au/action/externalEmbeddedPlayer?id=d-2r40g 620 349 August 2, 2013
The vast fossil deposit, located next to the Riversleigh World Heritage fossil site, was uncovered by a former student who, while studying the region with satellite images, noticed unusual patterns in the rocks.
In July, Fairfax Media accompanied a dig team to the location 200 kilometres north of Mount Isa, which is accessible only by helicopter, for its first major excavation.
Already one site revealed a treasure trove of animal bones, many yet to be identified, including a never-before-seen bat specimen, a couple of large wombat relatives called diprotodontids, small primitive marsupials and an ancient ring-tailed possum.
L-R, Emma Cohen, Phil Creaser, Professor Michael Archer, Rebecca Pian, and Associate Professor Sue Hand work at the newly discovered fossil deposit called Wholly Dooley. Outside the world heritage area Riversleigh in far North West Queensland. Photo: Tony Walters
''This place is bone city,'' said Professor Archer, who, after decades of fossil digs, admits he has become a discovery junkie.
He said one of the most intriguing features of the new specimens was that their teeth were worn.
The well-used dentures were distinct from those of most animals previously discovered at Riversleigh, which lived between 24 million and 15 million years ago, and suggested these new creatures were younger and ate a diet containing dust and grit, a symptom of a drier environment, Professor Archer said.
While Riversleigh is unique for its almost continuous and detailed 25 million year transcript of Australia's mammal groups - including the ancestors of our iconic koalas, kangaroos and wombats - there is a substantial gap in the record, between about 15 to 5 million years ago.
At this time, a period known as the Late Miocene, the rainforests that dominated northern Australia started to dry out.
''We know almost nothing about what happened in this area at that time,'' Professor Archer said.
A preliminary assessment suggests the animals exhumed from the new location roamed the landscape at this critical time.
With support from the National Geographic Society, a team of cavers and explorers located another eights sites containing bone deposits.
''This is such an important place to us,'' he said.
Palaeontologist Troy Myers said despite their small size, teeth could reveal a lot about their owner.
''And teeth are the hardest part of the body so they're the most likely part to be preserved,'' he said.
The fossils would likely have remained a secret were it not for a former UNSW student, Ned Stephenson, who used satellite images to view the original Riversleigh site.
As well as accurately locating the known fossil deposits in the Riversleigh area, he saw the same pattern stretched far beyond the world heritage boundary.
While the team is not sure of the exact source of the signal on the satellite images, it suspects it is related to the types of rocks, known as tertiary limestone, where Riversleigh fossils are typically located.
''It's a new potential way of locating fossils without having to wear your shoe leather out walking around on the hills,'' Professor Archer said.
Dr Myers and fossil preparator Anna Gillespie will now spend months preparing the 1.8 tonne of limestone rocks for more detailed analysis.
''This is just the beginning of new Riversleigh,'' Professor Archer said.