A newly described fossil goose shows that New Zealand’s bird history involved repeated arrivals, extinctions, and rapid island evolution.
A rare fossil goose found in the remains of an ancient lake in Central Otago is changing how scientists understand the bird history of Aotearoa New Zealand, according to a researcher at the University of Otago at Ōtākou Whakaihu Waka.
Associate Professor Nic Rawlence, Director of the Otago Paleogenetics Laboratory, coauthored a new paper examining the fossil and where it fits in the evolutionary record.
The study, published in Historical Biology, brings together researchers from Otago, the Museum of New Zealand Te Papa Tongarewa, and the University of Cambridge (UK) to analyze fossils collected near St Bathans.
Associate Professor Rawlence says the fossil beds in the region contain many common waterfowl remains, but some species appear only rarely.
Fossil bones reveal a new species
The researchers took another look at all remains that had previously been assigned to geese. They compared those bones with other waterfowl fossils from the site and with a wide range of modern and ancient bird skeletons.
“We determined that the bones included an undescribed species, the size of a small goose,” he says.
The team named the St Bathans goose Meterchen luti, drawing on the nursery rhyme Old Mother Goose. In this case, the name refers to an ancient goose emerging from the mud of a fossil deposit. Meterchen means “mother goose” in ancient Greek, while luti is Latin for “of the mud”.
“The St Bathans goose is not closely related to the recently-extinct giant flightless New Zealand geese (Cnemiornis species) or their Australian cousin, the Cape Barren goose.”
New arrivals reshape evolution
Together with other recent genetic findings, the discovery suggests that the origins of New Zealand’s birds were more complex and changeable than scientists once believed.
Lead author Alan Tennyson, of Te Papa, says many bird species reached New Zealand at different points in geological history. The ancestors of several large birds, including takahē, Forbes’ harrier, and the giant Haast’s eagle, appear to have arrived surprisingly recently, within the past four to five million years.
“An earlier theory argued that the St Bathans goose represented the direct ancestors of giant flightless Cnemiornis geese, implying this lineage had a very long history (of at least 14 million years) in Zealandia,” he says.
“However, this conflicts with genetic evidence suggesting the ancestors of Cnemiornis arrived from Australia only about seven million years ago, which proponents of the earlier theory discarded.
“Our rigorous reassessment supports the later arrival theory.”
Island birds changed quickly
Associate Professor Rawlence says the ancestors of the St Bathans goose reached Zealandia more than 14 million years ago, but their line did not leave surviving descendants.
“Using all the tools in the toolbox, including DNA and fossils, we can reconstruct how the dynamic geological, climatic, and human history of Zealandia has shaped the evolution of Aotearoa fauna in ever more detail,” he says.
“The relatively recent evolution of the giant flightless Cnemiornis geese offers another striking example of rapid morphological change that can occur within a short timeframe on islands. At one meter tall and weighing up to 18kg, these were the largest geese in the world.”
Reference: “A review of fossil goose (Aves: Anserinae) records from the Miocene St Bathans deposits, New Zealand, with the description of a new species” by Alan J. D. Tennyson, Elizabeth M. Steell, Pascale Lubbe, Amy L. Adams, Liam Greer, Alex H. Brown, Laura J. E. Wilson, Timothy C. Campbell, Tobia C. Dale and Nicolas J. Rawlence, 17 February 2026, Historical Biology.
DOI: 10.1080/08912963.2025.2601236
This research was supported by the Te Papa Collection Development Fund (2001–2025), a Phyllis and Eileen Gibbs Travelling Research Fellowship, Newnham College Cambridge, to EMS (2023–2025), a Marsden Fund Fast-Start Grant [16-UOO-096] to NJR (2017–2020), a Marsden Fund Fast-Start Grant [MFP-CTM1601] to V. De Pietri, G. Mayr and R. Scofield (2017–2020), a Kitty Southern Student Research Grant to LG and NJR (2019), Australian Research Council Discovery projects [DP120100486] to S. Hand, T. Worthy, S. Salisbury, R. Scofield and AJDT (2012-2014) and [DP0770660] to S. Hand and M. Archer (2007–2009), and funding from the Foundation for Research Science and Technology to T. Worthy (2001–2005). Te Papa, the University of Otago, Flinders University, Canterbury Museum, the University of New South Wales, the University of Queensland and numerous volunteers contributed financial and in-kind support.
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