A team led by Carolina Acosta Hospitaleche, a professor of vertebrate paleontology at the National University of La Plata in Argentina, has discovered fossils of a previously unknown giant bird in Antarctica. The find includes two 8-centimeter claws from this mysterious feathered creature, preserved in Eocene deposits of the La Meseta Formation on Seymour Island. These fossilized claws are about 50 million years old. Reconstruction of the extinct bird suggests it stood two meters tall and weighed around 100 kilograms. Researchers speculate it may have terrorized Antarctica’s fauna during a period when the continent enjoyed a much warmer climate.
“Large continental predators were absent from Antarctic communities back then. Among birds, we only knew of a daytime predator and small insectivorous marsupials. We had never found giant predators until now,” Carolina Acosta Hospitaleche explained.
Rather than the usual haul of small mammal fossils found on Seymour Island, the scientists unearthed two elongated fossilized claws. At first, the team thought the claws might belong to a large bird commonly called a “terror bird.” That label usually applies to members of the extinct family Phorusrhacidae, which were agile, active predators. The claws could belong to that group, but the fossils’ age and the lack of other skeletal material prevented Acosta Hospitaleche and her colleague Dr. Washington Jones from definitively classifying the specimen as a phorusrhacid.
Still, they think this formidable bird, likely a heavyweight predator, may be related to that family or to a similar group of large feathered predators. The scientists suggest these birds primarily preyed on small to medium-sized vertebrates, such as marsupials and ungulates (a group that includes modern pigs and deer). With long claws and sharp, hooked beaks, these massive birds could have dispatched their prey quickly, as reported by IFLScience.
The researchers say these birds could have been apex predators, sitting at the top of the food chain with no other animal or bird able to hunt them. “This discovery definitely changes our understanding of the dynamics of early Eocene Antarctic continental ecosystems,” they added. The team hopes many more fossils will be found to reveal further details about these fierce predators and the environments they inhabited millions of years ago. Erosion may aid scientists in that search. “Due to significant erosion, Antarctic islands reveal new fossils each year. This gives us a unique opportunity to learn more about ancient Antarctic ecosystems,” the team leader said.
The findings were published in the journal Palaeontologia Electronica.
