An artist’s impression of the St. Basangan, which once lived in New Zealand.
photograph: Sasha Votyakova/Te Papa Tongarewa
from early to middle MioceneBetween 14 and 19 million years ago, a vast lake covered much of what is now Central Otago.
along the coast of Lake Manuhelikiawhose remains have now been discovered nearby. st bathanslived crocodile, tortoiseand Bowerbirdand early relatives batmore, kiwiIt is home to a wide variety of waterfowl, including . duck And a swan.
This lost ecosystem is known today by famous records. St. Bassands Fossil DepositsIt preserves one of the world’s richest records of the Miocene and provides a rare window into Aotearoa’s warm, subtropical, ancient past.
our Newly published research Another waterfowl species will be added to this remarkable zoo. It also sheds important new light on the recent origins of New Zealand. Extinct flightless giant goose of the genus Nemiornis.
New Zealand’s long-lost waterfowl
Spanning 5,600 square kilometers, Lake Manuherikia was 10 times the size of New Zealand’s lakes. lake taupo. It was a dynamic habitat that supported a variety of waterfowl, including five shelducks and one duck. swantwo shelduckone duck hanging out and our new goose.
Many of these waterfowl are incredibly common in the fossil deposits around St Bassands, but other waterfowl, including the largest species, are extremely rare.
Our team has re-examined all bone remains that have been previously identified as belonging to geese. They then compared them to other large waterfowl bones obtained from the deposits and to an extensive collection of comparison bird skeletons kept at museums. New Zealand Museum Te Papa Tongarewa.
We determined that the bones contained an undescribed species about the size of a small goose.
We named our new bird Maeterchen Ruti, a Saint Basangan, a play on a nursery rhyme. ”old mother gooseIn our case, an ancient goose is rising from the mud of fossil deposits. Meterchen means “mother goose” in ancient Greek, and luti means “of mud” in Latin.
Ancient lake mud around St Bathans, Otago, is a rich source of fossils that give paleontologists unique insights into Zealandia’s past biodiversity.
photograph: Alan Tennyson/New Zealand Museum Te Papa Tongarewa
Ten unique waterbird species of varying sizes have been identified in fossil deposits, and Lake Manuhelikia was clearly a highly productive and dynamic lake system, supporting a large and complex ecosystem.
Not as old as first thought
Although our St. Bathand’s goose is based on only fragmentary remains, it is sufficiently preserved to show that it is not a close relative of the St. Bathand’s goose. A giant flightless Cnemiornis geese and their Australian cousins cape barren goose Cereopsis novaehollandiae.
An artist’s impression of an extinct flightless New Zealand goose that lives in a vast habitat.
photograph: Paul Martinson/Te Papa Tongarewa
Recent genetic studies indicate that the evolutionary origins of New Zealand birds are: more dynamic than previously thoughtDue to the influx from Australia, south america, northern hemisphere and unknown place.
Throughout geological history, many birds have visited this area. Zealandianow a mostly submerged continent that includes New Zealand. But the ancestors of some of our large birds arrived here surprisingly recently, within the past 4 to 5 million years. Takahe, Isles or Forbes Harrier and the giant Hurst’s Eagle.
Ann previous theory They claim that the St. Basangan is a direct ancestor of flightless giant geese, suggesting that this lineage has existed in Zealandia for at least 14 million years.
However, this contradicts genetic evidence This suggests that Cnemiornis’ ancestors arrived from Australia just 7 million years ago, but proponents of the earlier theory abandoned this.
Our reassessment, based on a much broader range of comparative bird skeletons rather than a single specimen, does not support the early arrival hypothesis, but instead favors the late arrival hypothesis.
Sales and transformation
In our interdisciplinary research, Significant levels of biological turnover Throughout the history of Zealandia.
The ancestors of the St. Basangan undoubtedly arrived in Zealandia 14 million years ago, but no descendants remain, and the ancestors of the giant Kunemiornis geese settled much more recently, but their descendants became extinct due to overhunting and plundering shortly after the arrival of humans.
The relatively recent evolution of the Kunemiornis goose, a giant flightless goose, provides another striking example. rapid morphological changes It can happen in a short period of time on an island where evolution can be rampant. It was the world’s largest goose, measuring up to 1 meter tall and weighing 18 kg.
Using all the scientific tools in our toolbox, we can reconstruct in greater detail how Zealandia’s dynamic geological, climatological and human history has shaped the evolution of Aotearoa’s fauna.
Each new discovery reminds us of its story. birds of new zealand – And as for Zealandia itself, I’m still writing about it.
* Nick Lawrence is Associate Professor of Ancient DNA at the University of Otago. Alan Tennyson is Curator of Vertebrate Zoology at Te Papa Tongarewa Museum, New Zealand.
– this story First appeared on The Conversation.