New research could rewrite prehistory

PHIL REID/Dominion Post

WAKE-UP CALL: Dr Hamish Campbell at Te Papa. His theory could change thinking about the evolution of New Zealand wildlife.

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New research is courting controversy with claims New Zealand was underwater till 23 million years ago.

The findings could debunk the "Moa's Ark" theory that this country's native species developed in isolation on a landmass that had existed for 85 million years - and the widely held belief that tuatara had been in New Zealand since the dinosaur age.

A report, co-authored by Wellington GNS biologist and fossil expert Hamish Campbell and Massey University molecular biologist Steve Trewick, suggests native flora and fauna may have begun their evolution in a different country - before drifting here once New Zealand emerged from the ocean's depths.

The controversial findings are expected to spark rigorous debate among scientists.

Dr Campbell said Australia was the most likely country of origin but a large island that existed north of New Zealand and had since submerged, was another possible source.

Conventional thinking is that New Zealand split from the ancient super-continent Gondwanaland 85 million years ago and has remained above the ocean ever since.

But Dr Campbell said his study on the Chatham Islands cast that assumption into doubt.

The Chathams were submerged till 3.5 million years ago, and the islands' wildlife had only been separated from their mainland counterparts for between two and three million years.

"The geological evidence for continuous land is so weak that it cannot be assumed."

Dr Campbell said, if his findings were correct, the entire theory behind the evolution of New Zealand's wildlife would need to be re-examined.

Award-winning biologist George Gibbs said Dr Campbell had ignored "a lot" of evidence in coming to his conclusions, but the research would serve as a "wake-up call" for scientists.