New fossil evidence shows that Australia's fire-prone shrubland open vegetation originated at least 70 million years ago -- 40-50 million years earlier than previously thought.
The findings, published online ahead of print in the American Journal of Botany, reject prevailing wisdom that Australia was covered with rainforest until 40 million years ago, and that currently dominant native vegetation types evolved after that on a drying continent with increasing fire.
"I grew up and started working believing that this iconic Australian vegetation evolved under the influence of fires as the rainforests dried out, largely over the last 25 million years or so. But it now looks like our fire-prone vegetation has much more ancient origins," says co-author Professor Bob Hill, Executive Dean of the University of Adelaide's Faculty of Sciences.
"This dryland, fire-prone vegetation actually precedes the mega-rainforests and it somehow managed to survive through the wetter times."