Time was when you could recognise an Aboriginal quite easily. They weren't wearing trousers.
These days, with loins covered, it is so much more difficult to be certain. This is important because no white Australian wants to commit the social faux pas of offering poisoned flour to the wrong sort of person, which can give grave offence.
The fetching young lady at the centre of the photo above, the fittingly named Ms Lilly Brown, is an Aborigine for sure. You can tell because she is flanked by two other Aborigines, and if her tribal companions are not enough, then that Indigenous scarf is irrefutable proof. After finding a Business degree just a bit too hard, she packed her dilly bag and went global walkabout with a lovely blackfella scholarship to underwrite extended stays in Canada and Cambridge.
Still, racial identification would be easier if she left her trousers off, like the fellows below.
Seriously, as there is no indication either dancer has obtained a foreign-study scholarship, how would anyone know they were Aborigines otherwise?
(H/T to Nilk at Catallaxy for her remarkable clairvoyance.)