An incomplete ulna ofDiprotodon optatumOwen from a Pleistocene site in Reddestone Creek, northwest of Glen Innes, New South Wales, has deep cuts on opposite sides of the shaft. These marks are attributed toThylacoleo carnifexbecause some of the cuts were made by blade-like teeth at least 2 cm in length, because they fit well within the jaws ofThylacoleo, and because teeth ofT. carnifexhave been found at the same site. Many other bones of extinct marsupials from Reddestone Creek are gnawed, broken or smashed. Much of this damage could also be attributed toThylacoleo, and so it is necessary to be particularly cautious when attempting to use bone damage of extinct Australian marsupials as evidence for predation by man.