In the first recorded case of a plesiosaur from the Jurassic period discovered in Antarctica, remains from the carnivorous sea reptile – which exceeded six meters in length – has been located at a new paleontological site 113 kilometers southwest of the Marambio Base in the Seymour Island.
Paleontologist José Patricio O’Gorman, a researcher at the Museo de la Plata (MLP) and CONICET, told the Agencia CTyS-UNLaM that “this plesiosaur record is 80 million years older than what was known for Antarctica.”
“It was the first paleontological campaign that we conducted in this outcrop (which is) like a frozen sea of ??150 million years in an excellent state of conservation,” said the lead author of the study, which has been accepted for publication in the scientific journal Comptes Rendus Palevol.
Dr. Soledad Gouiric Cavalli, MLP and CONICET specialist in the study of Jurassic fish, claimed that “when walking through the site you can find a great diversity of fish, ammonites, some bivalves, but we did not expect to find a plesiosaur of such age; It was surprising.”
“The finding is quite extraordinary, because in the site there is not the kind of rocks in which you can find preserved materials in three dimensions, as is the case of the vertebrae of this marine reptile,” explained the researcher.
During the 2016 summer Antarctic campaign, Dr. Gouiric Cavalli, Dr. José O’Gorman and technicians Juan José Moly and Leonel Acosta Burllaile camped for 40 days at the site, which is a two hour helicopter flight from the Marambio Base.
“It was very exciting to get there, to a place that nobody had stepped on in 23 years,” O’Gorman said.
Dr. Marcelo Reguero, researcher of the MLP and director of the paleontological campaigns of the Instituto Antártico Argentino (Argentine Antarctic Institute – IAA), stated that ” it was necessary to make a lot of logistics to get to this new paleontological site located in Cape Longing and the result was very successful, have rescued a great diversity of fish, plants and this plesiosaurus, and this summer we will go to the new campaign with even greater expectations.”
Reguero went on to say: “In the 2016 campaign, a large amount of fossils was obtained and for the expedition next summer we will go with instruments to obtain an even greater number of specimens.”
Dr. Gouiric Cavalli, who will be part of the new campaign taking place there from January 8 to mid-February, explained that “there is a surprising amount of fish there and it is logical to think that the plesiosaurus that we discovered would feed on them, because it is a large marine reptile and we found medium-sized fish, some smalls, and some quite large too.”
About the excellent conservation of this fauna and marine flora of the Jurassic, the MLP and CONICET researcher says “they were preserved because the bottom of that sea had very little oxygen, so there were no organisms that could dismantle those specimens and the phenomenon of putrefaction did not take place either.”
The world 150 million years ago
Dr. Marcelo Reguero stated that “these rich and unique deposits in marine Jurassic vertebrates belong to the time when Antarctica was part of the Gondwana continent and was next to Australia, New Zealand, India, Madagascar, Africa and South America.”
150 million years ago the temperature of the seas was much higher and the world map was very different.
According to Dr. José O’Gorman, this plesiosaurus – besides being the first of its kind in the Jurassic in Antarctica – serves as evidence in favor of the possibility of the dispersal of these reptiles by means of a passage that existed between Africa and Antarctica, which at that time had just separated.