To provide the best support for the claim that Aboriginal populations arrived in Australia shortly after 50,000 years ago, I'd need to see specific selections from the article you are referring to. Since I don't have access to the article, I recommend looking for information that includes archaeological evidence, genetic studies, or historical migrations that indicate the timing of Aboriginal arrivals in Australia and any related findings that support a timeframe around 50,000 years ago.
If you can share excerpts or details from the article, I can help analyze which ones would best support the claim.