A group of paleontologists say weird flesh-eating, galloping kangaroos once inhabited parts of Australia.
The team from the University of New South Wales says its latest dig at the Riversleigh fossil fields in north-west Queensland has uncovered new evidence of the ancient kangaroo, along with a creature they describe as the "demon duck of doom".
The team says the two-week expedition has found fossilised remains from at least 20 previously unknown species.
Professor Mike Archer, the Dean of Science at the University of New South Wales, says the kangaroo lived in the Riversleigh region somewhere between 10 million and 20 million years ago.
He says marsupials would not look like anything we recognise today.
"Because they didn't hop, these were galloping kangaroo, with big powerful forelimbs, some of them had long canines like wolves," he said.
"You could have been looking for Skippy but you would not have seen Skippy, you might have found his ancestor, who ended up eating you while you looked for the normal kangaroo."
Also on the dig was Dr Sue Hand, a vertebrate paleontologist who has given the flesh-eating kangaroos her own description.
"This group of animals we affectionately call killer kangaroos; well muscled in teeth, not for grazing, these things had slicing crests that could have crunched through bone and sliced off flesh," she said.
Dr Hand says the latest fossil discoveries show that the killer kangaroos were not the only frightening creature around 10 million years ago.
"Very big bird ... more like ducks, earned the name demon ducks of doom, some at least may have been carnivorous as well," she said.
The team will now begin a detailed study of the fossils they have brought back to learn as much as they can about the previously unknown species, and how they were affected by changing climates.
Dr Hand says it is fascinating work.