In my last column, I spoke of the mysterious Denisovans, a new hominid species only discovered in 2010.
They are significant to Australian history because it is clear that the ancestors of both the Papuans and Australia's Aboriginal peoples met and mated with them on their journey to Sahul, the name given to the continent of which both Australia and Papua New Guinea were once part.
Over the next few columns I will tell you a little of the remarkable story of Aboriginal occupation of Sahul, including New England. It's a story still shrouded in mystery and uncertainty, but we know enough now to at least paint a broad picture.
We do not know exactly when the ancestors of Australia's Aboriginal peoples arrived on Sahul. The earliest date we have comes from excavations at the Madjedbebe rock shelter in Kakadu near Jabiru. There earliest occupation was dated to 65,000 years plus or minus 5,000 years.
There have been some suggestions of earlier possible dates based on circumstantial evidence such as fire patterns. Most recently, an excavation at Moyjil Port Ritchie near Warnambool identified a possible hearth dating to 120,000 years ago. However, the team was cautious in their conclusions in the absence of any associated artefacts.
The evidence from Madjedbebe also suggests a sophisticated material culture from an early date. This is consistent with an emerging body of evidence that suggests that earlier hominin species including anatomically modern humans were far more advanced and at an earlier period than previously realized.
This bears upon the question of just how the ancestors of the Aboriginal and Papuan peoples reached Sahul.
The old view based upon then perceptions of "primitiveness" saw the original settlers almost as castaways, small groups who came by accident. This now seems highly unlikely and for two reasons.
The first is that we now know that earlier peoples were far more capable of crossing open water than previously realized. The great voyages from East Asia into Polynesia are a later and very dramatic example.
The second reason is that population analysis suggests that the survival and then expansion of the early human occupants of Sahul required a minimum foundation population measured in at least the low thousands.
To my mind, there are likely to have been a number of movements spaced over time, possibly using different paths.
We don't know what caused these migrations.
It may have been because of population pressures on existing ranges or because of pressures created by in-migration from other groups. There may have been natural disasters or, perhaps, just the normal human spirit wishing to explore new territories.
We may never know the answers here. However, we do know more about what happened once the Aboriginal ancestors reached Sahul.