BUENOS AIRES (CTYS).- Investigators of the Plata Museum, the CONICET and the Argentine Antarctic Institute, with the collaboration of a German investigator, discovered the fossil remains of two mammals (similar in size to a sheep) in proximity to the Marambio Base. Both examples, 55.3 million years old, represent the most ancient evidence about the presence of terrestrial mammals in the Antarctic continent, although PhD Javier Gelfo is convinced that during the next summer campaign they will search for even more primitive remains.
The mammals discovered were herbivores characterized by the hoofs that covered their toes in each of their four legs. They were found close to the Marambio base in Seymour Island, a site in the early Eocene where they also discovered the remains of shark teeth, mollusks and penguins.
One may wonder how these terrestrial animals could be found along these marine species and the answer is that after their death, they were transported by ancient rivers from continental areas to the rivers mouth, explained Gelfo, investigator of the Paleontological Division of Vertebrates in the Plata Museum.
The tooth was attributed to a mammal of the family Sparnotheriodontidae of the extinct order Litopterna, which had ample distribution in South America during the Cenozoic. However, when these animals lived, the Antarctic had been separated from the rest of the continents for about five million years, although it still had a tropical climate and an ecosystem of forests that fed these species.
In the next expedition, Gelfo expects to find even more ancient mammals fossils: We are preparing the 2015 summer campaign, which is organized by the Argentine Antarctic Institute, and we will search for much more primitive mammal fossils.
The importance of this discovery is that it sheds light on new information about the evolutionary history of these native mammals in South America and, it indirectly gives researchers more details about the marine separation of the Antarctic and Patagonia.
From studies conducted on the tooth, an inferior molar, scientists can notice there is an evolutionary difference from this mammal to those who lived in South America which can only mean they had been separated by approximately five million years.
This difference is another element that helps us understand that the disappearance of the terrestrial connection with the Antarctic was produced during the late Paleocene, some 60 million years ago, although we cannot pinpoint exactly when, added the paleontologist.