Original: Nature 445:422 -425 The dates derived show that all forms of megafauna became extinct in the same rapid timeframe - approximately 47,000 years ago - the period of time in which humans first arrived in Australia.
Simplified: Nature 445:422 -425 The dates show that the last of the megafauna became extinct around the same time, about 47,000 years ago. This was the time in which humans first arrived in Australia.