Last updated February 28, 2018 at 9:51 pm
Scientists have identified the fossilised bones of two new species of flightless birds of a miniscule scale.
But not all birds were giants.
New research examining fossils from the area that surrounded an ancient lake in New Zealand have identified two new species of birds, called rails, that lived 16-19 million years ago. And they were tiny, barely bigger than the modern sparrow.
The finds join a host of other fossil birds recovered from these deposits that show New Zealand has long been a land of birds.
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New Zealand was a haven for flightless birds
Small flightless birds only exist in the absence of terrestrial mammalian predators, and New Zealand has long been recognised as the iconic location for flightless birds, which evolved in the absence of such predators.
“Flightlessness in birds is often associated with an increase in size,” says Ellen Mather from Flinders University, the study’s lead author.
“The weka, which is in the same family as our fossil birds and lives in New Zealand today, is about the size of a chicken. The Banded Rail, their closest flying relative, is about half that size.”
Where did they come from?
The discovery of these two miniscule flightless rails raised the question of ‘Where did they come from?’ The researchers suggest they had ancestors in Australia and had flown across the 1,500 km ocean in previous millennia. However, the new species are unlike any rail known elsewhere so their exact origin or closest relatives remain a mystery.
Professor Mike Archer, from the UNSW PANGEA Research Centre, says the latest discoveries emphasise NZ’s natural history as one of the world’s “most extraordinary engines driving bird evolution”.
“Charting how lineages like these rails have changed through time on an island that has been geographically isolated for over 80 million years will test basic presumptions made about bird evolution in general,” Professor Archer says.
The research was published in the Journal of Systemic Palaeontology.