New species of bird discovered that lived during the Ice Age

This is a specimen that belongs to the group of Patagonian bustards or cauquenes, distant relatives of geese. The bones were found more than two decades ago, but it was only recent research that determined that they belong to a new species.

Cold, dry climate and vast expanses of arid steppes. It is unthinkable to link this Patagonian landscape with an Argentine province that is now known for its endless plains and humidity, but this is what Buenos Aires was like more than 100,000 years ago.

In this environment, among sabre-toothed tigers, mastodons, giant sloths and car-sized glyptodonts, lived species with a much smaller body size, such as birds. Although their remains are difficult to find, recently, a team of researchers from the Argentine Museum of Natural Sciences Bernardino Rivadavia (MACN), attached to the National Scientific and Technical Research Council (CONICET), with the help of the Azara Foundation and the National University of the South (UNS) made a great discovery: they identified a new species of cauquén that belonged to the Ice Age.

This is Chloephaga dabbenei, named in honour of Roberto Dabbene, the father of bird studies in Argentina. This new species, belonging to the group of Patagonian bustards or cauquenes, fed mainly on grasses and grains and was often hunted by man, which, together with environmental modification, brought many of them to the brink of extinction.

In this regard, Federico Agnolín, a paleontologist and researcher at MACN, highlighted the importance of this work by explaining that bird bones are very difficult to find due to their fragility and size, which makes their fossilization difficult. “In general, loose and incomplete bones are found and, therefore, we know almost nothing about the past history of living birds,” he told the CTyS-UNLaM Agency.

In this sense, the study, which has been published in the academic journal Comptes Rendus Palevo, is of great relevance, since its authors managed to identify several complete and well-preserved bones that could help to learn more about the evolution of the group. “The fossils had been found more than two decades ago during detailed studies carried out by geologists and paleontologists in Bahía Blanca, but they were never studied until they reached our hands, approximately one year ago,” said Agnolín.

Traces of a lineage

The new species is part of the cauquenes lineage and was much larger than the current species, as researchers estimate that it could weigh up to five kilos. Currently, there are about four species of this lineage distributed mainly in Patagonia, which can migrate to the south of the province of Buenos Aires during the winter.

Reconstruction of Chloephaga dabbenei made by the artist and biologist Martín Colombo.

“Living great bustards look like goose and we think that Chloephaga dabbenei would have been similar. Obviously, we don’t know the details of the arrangement of the feathers or the colours, since these are not fossilised, but the muscle marks are deep, which indicates a stronger musculature and a larger size and robustness than the living ones,” said Gerardo Alvarez Herrera, a member of the MACN research team.

In addition, he explained, the tarsometatarsus bone, which forms the largest part of the leg, has a series of features that “make us think that it was a more walking species and possibly also less aquatic” than the current ones. “In this case, it is the first extinct species known for the lineage,” he stressed.

About 10,000 years ago, the climate became warmer, large ice blocks began to melt and slowly disappear. With this extreme climate change, many species ceased to exist. The Chloephaga dabbenei, along with a whole range of typical Ice Age fauna, also became extinct.

According to researchers, it is possible that this species was closely adapted to living in the arid pampas of Buenos Aires at that time, and the change in climate and habitat led to its disappearance, while its close evolutionary relatives managed to survive.

“This discovery shows that several species of birds that existed in our pampas became extinct towards the end of that era. Some paleontologists had thought that this event had not affected birds, but with this work we have added evidence that indicates the opposite,” Agnolín explains. (Source: Marianela Ríos (Agencia CTyS-UNLaM))