The discovery of "Mungo Man" in 1974, named after the dry outback lakebed where the fully intact skeleton was found, doubled the known length of humans' presence on the continent from 20,000 to 40,000 years.

But the bones' removal to Canberra for study, roughly 600 km (370 miles) east of Lake Mungo, had angered the indigenous community there.

"We've been waiting all those years to get him back and I'm so glad he is back, to put him in his resting place," said Joan Slade, an elder of the Aboriginal Ngiyampaa people at a ceremony welcoming the remains back to her ancestral country.

The skeleton, along with 104 other remains, arrived in a black hearse with the black, yellow and red Aboriginal flag painted on its side.

Read: Iriana Widodo and Lucy Turnbull Tour of the Aboriginal and Torres Strait Islander Collection

A traditional smoking ceremony, with green gum-leaves burned over a small fire, welcomed the remains back to the red soil and saltbush scrub of Lake Mungo.

"This, today, is one of those catalytic moments...it makes us, the traditional owners, custodians of our culture," said elder Michael Young.

"They will be kept in a secret, safe place so that we can pass on to the next generations the legacy that these people have given us."

Though subsequent discoveries have pushed back even further the date of humans' first arrival in Australia, the finding of Mungo Man was at the time a huge advance for understanding human history.

His burial, with limbs stretched out, hands crossed across his groin and covered in an ochre drawn from some 200 km away, helped prove the ancient age of Aboriginal civilization - the world's oldest continuing culture - dating back around the time Neanderthals occupied Europe.

The Australian National University, whose researchers removed the remains, issued a formal apology when it turned the remains over to the region's Aboriginal custodians in 2015.

"We recognize that the removal of these ancestral remains caused ongoing grief to your communities and we apologize unreservedly," it said.

"While the research undertaken...contributed significantly to the understanding of the history of indigenous Australians, our research in the past has not always been undertaken with your full knowledge and support."

REUTERS