Australian and New Zealand scientists have unearthed the remains of ancient wildlife in a cave near Waitomo, the first time a large number of million-year-old fossils have been found in Aotearoa New Zealand.
The discovery of fossils from 12 ancient bird species and 4 frog species has opened a rare window into how New Zealand looked about 1 million years ago. It indicates that New Zealand’s ancient wildlife was significantly impacted by catastrophic climate changes and volcanic eruptions. This resulted in frequent extinctions and species replacements well before human arrival.
The research is published this week in Alcheringa: An Australasian Journal of Palaeontology.
Co-author and Canterbury Museum Senior Curator of Natural History Paul Scofield says, “From our excavations at St Bathans in Central Otago over many years, we have a snapshot of life in Aotearoa between 20 and 16 million years ago. These new findings cast light on the 15 million year period from then to 1 million years ago, which is largely absent from New Zealand’s fossil record.
“This isn’t a missing chapter in New Zealand’s ancient history, it’s a missing volume.”
One of the most significant finds is a new species of parrot, Strigops insulaborealis, an ancient relative of the Kākāpō. While the modern Kākāpō is famous for being a heavy, flightless parrot, this newly described ancestor may have been able to fly. Analysis of the fossil suggests it had weaker legs than its modern descendant, implying it was a less adept climber. More research is required to confirm whether the ancestor could fly.
The cave also yielded an extinct ancestor of the modern Takahē, which allows researchers to track the evolution of this iconic New Zealand bird, and an extinct species of pigeon closely related to Australian bronzewing pigeons.
Lead author and Flinders University Associate Professor Trevor Worthy says the study breaks new ground.
“This is a newly recognised avifauna for New Zealand, one that was replaced by the one humans encountered a million years later,” he says.
“This remarkable find suggests our ancient forests were once home to a diverse group of birds that did not survive the next million years.”
The fossils were analysed by a team of palaeontologists from Flinders University and Canterbury Museum along with volcanologists Joel Baker from the University of Auckland and Simon Barker of Victoria University of Wellington.
The findings suggest that about 33-50% of species went extinct during the million years before humans arrived in Aotearoa New Zealand. Paul says this was driven by relatively rapid climate shifts and cataclysmic volcanic eruptions.
“The shifting forest and shrubland habitats forced a reset of the bird populations, says Paul.
“We believe this was a major driver for the evolutionary diversification of birds and other fauna in the North Island.”
The fossils could be accurately dated as they were between two layers of volcanic ash preserved in the cave. One layer was from an eruption 1.55 million years ago, while the other was from a massive eruption 1 million years ago. The more recent eruption would have blanketed much of the North Island in metres of ash. Most of it would have been washed away, but some would have been preserved in caves. The older layer found at this fossil site proves it is the oldest known cave in the North Island.
Trevor says the fossils “provide a critical, missing baseline for New Zealand’s natural history”.
“For decades, the extinction of New Zealand’s birds was viewed primarily through the lens of human arrival 750 years ago. This study proves that natural forces like super-volcanoes and dramatic climate shifts were already sculpting the unique identity of our wildlife over a million years ago.”
To cite this publication: The first Early Pleistocene (ca 1 Ma) fossil terrestrial vertebrate fauna from a cave in New Zealand reveals substantial avifaunal turnover in the last million years
Authors: Trevor H. Worthy, R. Paul Scofield, Sneha Suresh, Simon J. Barker, Colin J. N. Wilson, Paul W. Williams and Joel A. Baker
ALCHERINGA: AN AUSTRALASIAN JOURNAL OF PALAEONTOLOGY
https://doi.org/10.1080/03115518.2025.2605684