Scientists from Argentina and Chile have discovered a footprint in Antarctica left by a small land mammal that lived around 55 million years ago, according to a study published in the journal Polar Biology.
The footprint was found on King George Island, off the Antarctic Peninsula, and offers new clues about what life looked like on the continent during the Eocene epoch, the researchers said.
The animal that left the print weighed just 1.3 kilograms and was preserved in volcanic sediment for millions of years, according to the study. The team believes it belonged to a small predatory mammal related to today's marsupials, widening scientists' understanding of Antarctica's ancient ecosystems.
A tiny print points to an ancient predator
The fossil, catalogued as T-373, partially preserves the impression of a paw and a hand and measures about 2 centimeters. Researchers attributed it to a small metatherian belonging to the sparassodonts, a group of carnivorous mammals that lived in South America.
The find is significant because it is an ichnofossil, a trace left by an animal's movement rather than its bones. If the identification holds, it would be the first known record of a sparassodont in Antarctica and one of the oldest pieces of evidence of a land-dwelling carnivorous mammal in the region.
A warmer, greener Antarctica 55 million years ago
During the Eocene, Antarctica was far warmer than it is today and supported forested landscapes, according to the study. Land connections that still existed between South America and Antarctica at the time may have allowed animals such as sparassodonts to move between the two land masses.
The footprint also revises the picture scientists had of the predators that stalked Antarctica during that period. Until now, so-called terror birds were the main documented land predators there, but the researchers said the discovery shows carnivorous mammals also formed part of the Antarctic food chain.
