Back in January 2011 I wrote about contact between Homo sapiens and Homo neanderthalensis in Neanderthals r us as modern humans moved out of Africa about 45,000 years ago. I was troubled by the lack of mention of Australian Aborigines in the article the post was based on. At the time, from memory, it was thought that Australian Aborigines had been here 10,000 years earlier than that.
Later that year genetic studies suggested that Australian Aborigines came out of Africa into Asia about 70,000 years ago, or in the range of 64,000 to 75,000 years ago. A recent New Scientist article places the consensus view at 60,000 years ago, but cites evidence of new discoveries of human fragments dating back much further. Teeth found in a cave in China date from between 70,000 and 125,000 years ago. However, scientists cannot be sure that the teeth belong to a modern human.
However, other fossils are more convincing. Bones found in Israel, including an upper jaw from Misliya cave, could be 150,000 years old. In China, Trinkaus was involved in the identification of a jawbone and two molars from Zhirendong, a cave in Guizhou province (PNAS, doi.org/fxbjgj). Though the bone is over 100,000 years old, Trinkaus’s team says the shape of its chin is suggestive of modern humans.
Now we also have this:
A closer look at the genetics also suggests there was an earlier migration. Recently, Katerina Harvati of the University of Tubingen in Germany and her colleagues tested the classic “out of Africa at 60,000 years ago” story against the earlier-exodus idea. They plugged the genomes of indigenous populations from south-east Asia into a migration model. They found that the genetic data was best explained by an early exodus that left Africa around 130,000 years ago, taking a coastal route along the Arabian peninsula, India and into Australia, followed by a later wave along the classic route (see map) (PNAS, doi.org/tz6).
Here’s the map:
Not a certainty, but definitely a possibility.
Reports of this kind seldom mention sea level. Indeed some wax lyrical about the feat of sailing from Indonesia to Australia. During the last glacial maximum, about 22,000 years ago, the sea level was some 120 metres lower. This is a vegetation map of the world back then:
During the last ice age the sea level would have varied, but clearly at times there was more land exposed to our north. Crossing would have been easier, but evidence of coastal dispersals may be now deep under water.
A time scale of 130,000 takes us back to before the Eemian, the last interglacial period.
This article also suggests a gene flow between India and Australia some 4000 years ago.
It’s a fair bet that the more we know the more complex the picture will become. There is also the small matter of the Denisovans who interbred with modern humans east of the Wallace Line, which runs between Bali and Lombok and up the east coast of Borneo.