Did hominins really come Out of Australia?

This article has been published on Twitter as an atomic essay and connected threads. Here, it’s all in one. These essays are written up from my current research for a fiction project. Some areas may be erroneous, and some controversial. Just remember, these are the basis for fiction.

To follow the essays, please check out my pinned thread on Twitter: https://twitter.com/PacificBlue/status/1445876407117103106

Did hominins really come Out of Australia?

Although it’s commonly taught and there’s much evidence to suggest that homo sapien’s archaic hominin ancestors migrated out of Africa, there’s a number of contrary theories with some evidential support. The one I like, as I live in Australia, is what the title says — Out of Australia.

Let’s start, however, with Out of Africa again. Although the theory prevails that Africa is where all our ancestors came from, the theory has been tweaked over the years. Once it was thought that there was only one major migration.

Now we have multiple migration theories, placed at different time points. The biggest and latest is thought to have taken place 70,000 years ago. This was the southern migration where hominins eventually arrived in Australia around 65,000 years ago.

Australia keeps coming up with artefacts which push back those years. There are various artefacts in Indignous Australian sites which are dated possibly to tens of thousands of years before that.

Now let’s add in the eruption of Toba in Sumatra 74,000 years ago. The ash and smoke of that gigantic eruption wiped out most of Asia and Europe but left any downunder humans completely free and easy.

It also left Africa well enough alone, but any Africans migrating 72,000 years ago were hardly likely to travel out of their lovely clean homeplace through and down an ash-ridden Asia, yet the Out of Africa theory does suggest this.

But we do have the Northern Australians, at a time part of the Sahul shelf with New Guinea. And they possibly had boats too.

And then we have the Baob tree and a nose bone.

The Baob Tree has a rich history in Australian Aboriginal dreamtime and culture. Archeological evidence in the Kimberly region (Australia’s far north) shows the Baob features as early as 40,000 years ago.

Many Aboriginal elders suggest that Baob trees were known much earlier — that like themselves, both humans and the baob tree have been in Australia forever.

The Baob Tree in Australia is an enigma archeologically:

It is only found in the Far North, and its closest relatives are found on the other side of the Indian ocean — six in Madagascar, and the seventh closest relative, in Africa.

Three theories of how the Baob got to Australia are available although two can be reasonably dismissed. But until recently, one of the three was dismissed incorrectly.

The first is that the baob tree existed before the breakup of Western Gondwanna Land more than 100 Million years ago.

This would mean the Australian species should be 100M years divergent from the others. It’s not.

Another theory is that the Australian Baob grew from seeds transported across Indian Ocean currents. This is plausible if prevailing transoceanic currents were different a hundred thousand years ago than they are now. But who knows?

But the third theory used for the Australian Baob tree arrival is that it was carried in boats by a migrating hominin ancestor of ours.

The only issue with this theory, which supports the Out of Africa theory, is that it also supports the opposite — an Out of Australia theory of human migration.

Out of Australia as a theory is supported by two things. The Kimberly region has ancient rock artwork of ocean-going boats capable of transporting humans and Baob tree seeds across oceans.

And now here’s the grunter to the Out of Australia theory of human and Baob tree migration:

The genetic profiles of the Australian Baob and its closest relative, the African baobab.

The African baobab is tetraploid (four sets of chromosomes per cell) while the Australian baob is diploid (two sets).

It is rare for a tetraploid species to evolve backwards into a diploid species. The Australian is likely to be genetically older than it’s African relative.

Now let me discuss a nose bone (jewelry) made of kangaroo bone. For a long time, Australian prehistory was flawed.

Archeological evidence had been accepted that people got to Australia from 50–65,000 years ago, sure…

But they were thought to spend tens of thousands of years not developing tools.

This theory was developed because the earliest bone tools found until very recently were from only 20,000 years ago.

The story we were given was that the first humans arrived with tools, then forgot how to make them, then remembered again. With a 40,000-year gap!

Yes, you read that right.

In 1992 an archeological team in the Kimberlys (Northern Australia) uncovered a kangaroo point. It was only analysed in 2016 and found to be the world’s oldest bone tool in the world. Dated at 46,000 years old.

Then a stone fragment of the world’s oldest known ground axe of a similar age was also discovered in Western Australia.

So we now had a connection of tools and a piece of jewelry supporting a much earlier cognitive race of people in Australia that had previously been believed.

Could it be that Australia had cognitive people, capable of the creating and using the oldest tools on record, transporting themselves with boats, and taking seeds of an Australian tree to other countries tens of thousands of years ago?

Of course, all of these are only theories. We weren’t there with our microscopes or technology to audio record the oral histories of hominins passed down over tens of thousands of years.

But I do like to think of the Australian Baob as the original tree of life.

Links:

• Original twitter essay and thread: Twitter
• Image via: ABC: Curious Kimberley: Scientists disagree how boab trees got to Australia from Africa and Madagascar