A nearly-complete skeleton of an extinct, non-hopping kangaroo species has been painstakingly retrieved, piece by piece from a cave 20 metres underground.
Scientists have unearthed the "incredible" fossil of an extinct kangaroo that walked, rather than hopped around southern Australia 50,000 years ago.
In a precarious operation, the nearly complete skeleton of a short-faced kangaroo, simosthenurus occidentalis, took about two years to recover from deep within Nightshade Cave near Buchan in eastern Victoria.
The find is the most complete fossil skeleton ever discovered in a Victorian cave.
A team headed by Museums Victoria Research Institute palaeontologist Tim Ziegler abseiled 20 metres underground through a shoulder-width hole and stalactite-encrusted passages to recover the specimen, piece by piece.
"Part of the reason this skeleton is so exceptional is that it was in an exceptionally difficult place to reach," Mr Ziegler said.
"It was a protected wedge inside a cave in a vertical shaft covered by boulders that were washing water and sediment away from the bones."
Tim Ziegler says the rare find was retrieved from an exceptionally difficult place to reach.
Mr Ziegler recalled removing his shirt to use as makeshift bubble-wrap to ensure the precious skull made it out of the cave safely.
"There's not much that palaeontologist wouldn't do for a specimen as incredible as this," he said.
The team spent about 58 hours underground during the arduous two year process.
Short faced kangaroos were the most widespread and most successful variety of kangaroo in Australia for the last couple of million years, but with a key difference.
"Unlike its living cousins, simosthenurus occidentalis was more comfortable walking with a striding gait, similar to that of humans or Tyrannosaurus rex: it did not hop," he said.
"This near-complete and exceptionally preserved specimen is helping scientists revolutionise our understanding of the deep past of Australia's iconic fauna."
The fossil was first spotted by recreational cavers in 2011 but, noticing some degradation a decade later Mr Ziegler began work to safely retrieve and conserve it.
Parks Victoria rangers and recreational cavers played a crucial role in the delicate extraction.
"'This fossil skeleton was first seen and reported by members of the Buchan community," senior ranger Phil McGuinn said.
"They've made an invaluable contribution to the natural heritage of the Buchan Caves, to the local area and to scientific knowledge worldwide.'"
The fossil will be on public display in the Melbourne Museum's Research Institute Gallery from 24 June, ahead of the school holidays.