Forget cute, cuddly marsupials. A team of Australian palaeontologists say they have found the fossilised remains of a fanged killer kangaroo and what they describe as a "demon duck of doom".

A University of New South Wales team said the fearsome fossils were among 20 previously unknown species uncovered at a site in northwest Queensland state.

Professor Michael Archer said the remains of a meat-eating kangaroo with wolf-like fangs were found as well as a galloping kangaroo with long forearms that could not hop like a modern kangaroo.

"Because they didn't hop, these were galloping kangaroos, with big, powerful forelimbs. Some of them had long canines (fangs) like wolves," Prof. Archer told Australian Broadcasting Corp radio.

Vertebrate palaeontologist Sue Hand said modern kangaroos look almost nothing like their ferocious forebears, which lived between 10 million and 20 million years ago.