mice in that it had a very long tail.
The long-tailed hopping mouse was last seen alive in 1901. It differed from still-living hopping mice in that it had a very long tail (obviously, I guess!). It may still exist, but until a live specimen is found, it will continue to be classified as extinct. I'd like to think that somewhere in the outback there's a family of them happily hopping around doing what rodents do.