WELLINGTON, June 28 (Xinhua) -- A newly discovered fossil shows that ancestors of the Australian magpie lived in New Zealand 19 million years ago, reshaping the bird's history.

The magpie, introduced from Australia in the 1860s to control pasture pests, has become one of New Zealand's most controversial birds due to its aggressive attacks on people and other birds. Its presence has sparked ongoing debate over its impact on native wildlife and whether population control is necessary.

The discovery is the result of more than two decades of excavations at the St Bathans fossil site in Central Otago in New Zealand's South Island, a prehistoric lakebed that offers the only significant glimpse into the country's terrestrial wildlife from 16 to 19 million years ago, according to a release from New Zealand's Canterbury Museum on Friday.

The newly discovered St Bathans currawong, an all-black, magpie-sized bird from the Early Miocene and a member of the cracticine family, shows that magpies have ancient roots in New Zealand, challenging the idea they are only recent Australian arrivals, the release said.

"We persecute the magpie as an Australian that has no place in the New Zealand ecosystem, but its close relatives lived here in the past," said the study's co-author and Canterbury Museum Senior Curator Natural History Paul Scofield.

The St Bathans currawong vanished about 5 million years ago as climate cooling caused widespread plant and bird extinctions, Scofield said. Miocene New Zealand's forests, rich in Australian-type trees, supported far more songbird species than seen before human arrival, according to researchers.

The findings, published in the journal PalZ by researchers from Flinders University, the University of New South Wales, Canterbury Museum and the University of Canterbury, highlight the dynamic nature of New Zealand's biodiversity and the importance of the fossil record in understanding the region's constantly evolving ecosystems. ■