Found: Oldest bilby and bandicoot fossils Million-year-old fossils of Aussie icons found in archives of US university. A bilby. Credit: Jacob Layocan / Getty Images. A scientist from the Western Australian Museum has discovered the oldest known fossils of two iconic Australian animals – the bilby andthe bandicoot – which had been kept for decades at the University of Washington, US. Both the bilby and the bandicoot are small, furry, rodent-like marsupials found on mainland Australia and – in the case of the bandicoot – Papua New Guinea and parts of Indonesia. Three new fossil bandicoots named in the study. Credit: WA Museum. Previously, the oldest bilby (