Moa more closely related to South American flying bird than kiwi

The South American tinamous, and the extinct NZ moa. Photos / Thinkstock, File

A new study has put even more genetic distance between the extinct moa and their old bush mates, the New Zealand kiwi.

Rather, new research led by Toronto-based New Zealand scientist Professor Allan Baker suggests ther giant birds were more closely related to a flying South American bird still alive today than our national icon.

The study, published online in Molecular Biology and Evolution, used DNA to analyse family ties between a range of ratites, or flightless birds.

The South American tinamous, one of the world's most ancient living groups of bird, can fly and are not categorised as ratites, but are considered close relatives because of the shared structure of their palate bones.

In contrast, recent molecular studies suggested they may be more closely related to the extinct moa within the ratites.

While kiwi are also a ratite species, they and moa may have evolved independently to become flightless birds, according to the study.

To help pin down the evolutionary debate, Professor Baker's research team drew on ancient moa DNA, along with DNA from emus and other flightless birds to assemble the largest dataset to date.

Their results found convincing evidence that tinamous were indeed most closely related to the wingless extinct moa.

They showed that morphological characters of ratites interpreted on their molecular tree are mostly convergent, evolving independently, probably as an adaptation to an "on-the-run" lifestyle.

The findings are in line with a study published late last year by Adelaide's Flinders University, which suggested the kiwi did not evolve from the moa, but probably from an ancestor that flew in from Australia.

Palaeontologist Trevor Worthy said at the time that an ancestor of the kiwi dating back 20 million years discovered in the South Island was more closely related to another giant flightless bird, the emu, which is still common in Australia.

It appeared the fossilised South Island bird and the emu evolved from a common flying ancestor, which originated in Australia but also spread to New Zealand.

Dr Worthy said it was not uncommon for birds to "jump" from Australia to New Zealand, citing the mallard duck, the little banded dotterel and the cattle egret as three species that often flew back and forth.