On a recent trip to Western Australia my wife and I visited Jewel Cave just outside of Augusta. The cave was discovered in 1951. In the bottom of the cave they found the skeletal remains of a Tasmanian Tiger which has be dated at 25,000 BP. I was intrigued!
It shows that I haven't read enough about WA, but it was the first time I had heard of the Thylacine in the west. Apparently there have been quite a few discoveries. Two skeletons in the North, and many more in caves in the south east. Even more fascinating, I discovered that there are rock painting in Kimberly and other regions that show that aborigines probably domesticated Thylacines some years before the introduction of dingoes (reference).
Indeed, fossil remains have been found right across Australia and in New Guinea (reference).