Researchers find six new types of kiwi
New Zealand's national bird, the kiwi, is more diverse than previously thought, according to Canadian researchers.
Instead of the five known species, a team led by Toronto University biological sciences professor Jason Weir has identified 11 types - either species of subspecies - alive now, with another six extinct.
In collaboration with Department of Conservation scientists, the researchers examined a database of kiwi DNA, including 300 samples of kiwi blood.
The study, published in the US journal Proceedings of the National Academy of Sciences, concludes that ice age glaciations drove the evolution of kiwi into multiple lineages.
Earlier research appeared to indicated that kiwi had developed into various species before the Pleistocene ice age that began some 2.6 million years ago and ended about 11,000 years ago.
But by deploying new and more sophisticated DNA testing, Prof Weir's research shows kiwi underwent an "explosive" period of genetic diversification - evolving into new species or subspecies - during the middle and late Pleistocene period.
The study says that, as ice spread over the land, particularly on New Zealand's South Island, kiwi retreated to isolated refuges where they gradually evolved new characteristics over the course of tens of thousands of years.
This pattern was repeated continually as the ice expanded and shrank some seven times over a period of nearly 800,000 years.
Prof Weir is among the first to use the new DNA techniques to measure evolutionary changes.
He expects scientists to revisit evolutionary studies of many birds and animals in parts of the world that had periods of glaciation.
"These new methods are going to be used extensively in the next 10 years," he said.
"The old system is out the window now."
