BUENOS AIRES – The discovery in southern Argentina of the fossilized remains of a fierce aquatic reptile that roved the seas 66 million years ago has left many a paleontologist tingling with excitement, as the nearly-complete skeleton of the extinct predator promises to provide new clues related to the species’ evolutionary history and behavior.
The petrified bones unearthed back in 2009 after arduous excavation efforts in the Patagonian Lago Argentino lake once belonged to a plesiosaurus (from the Greek “plesios” – “near to” – and “sauros” – “lizard”), a genus of marine reptiles with long necks, turtle-like bodies with aquadynamic fins and small heads filled with rows of sharp teeth.
“These beings were ichthyophagists (a fancy word for “fish-eating”), possessed a small tail and a very broad and flat body, like a turtle but without the shell,” said Fernando Novas, the laboratory chief at the Bernardino Rivadavia Argentine Museum of Natural Sciences in Buenos Aires, which was set to dazzle visitors with a faithful recreation of the skeleton to be displayed hanging from the ceiling.
While plesiosaurus fossils are fairly common in Europe and North America, they are much more difficult to find in South America, which is why this particular skeleton is considered by experts to be so significant.
“This discovery is very important since it’s the first time they find such a complete and articulated skeleton that is very informative from an anatomical perspective and allows us to comprehend previously-unknown aspects of plesiosaurus’ morphology and evolution in the Southern Hemisphere,” Novas said.
It took researchers nine years and a lot of patience to complete the extraction of the bones from their rocky enclosure after the hard, granite-like block encasing the skeleton arrived at the museum.
“We had to use different kinds of tools to be able to break it apart in several ways to get to the bones,” Novas said, “but fossils are very fragile, so we had to work with high-precision tools such as specialized mallets to release the bones without damaging them.”
Paleontologists’ efforts had already been hampered during the excavations at the lake, as the weather conditions were harsh – the wind would sometimes reach speeds of 80-100 kilometers an hour (50-62 miles per hour), causing huge waves – and time was running short due to the summer melting of the nearby Perito Moreno glacier, which prompted water levels to rise and threaten the entire dig.
“Unfortunately, we lost the neck and the head, the waves probably swept them away,” Novas lamented.
However, based on what is known about the genus, scientists were able to reconstruct the missing parts by inferring the specimen’s probable number of vertebrae (55) and the skull’s size and morphology.
The beast once measured some 8 meters (26 feet) in length and had a width of more than 4 meters, a size comparable to several types of modern whales, although the closest living relatives nowadays are sea turtles.
“It’s not true that there’s a plesiosaurus living in Loch Ness, that’s just a fairytale,” Novas said, in reference to the popular folk monster some believe inhabits the Scottish lake. “These animals went extinct more than 65 million years ago.”
The event that caused the Cretaceous-Tertiary (K-T) extinction that wiped out the dinosaurs and most large reptiles who had ruled the Earth during the Mesozoic Era is now widely believed to have been the impact of a huge asteroid in what today is Mexico’s Yucatan Peninsula.
While it still lacks a full name, this particular plesiosaurus could soon be christened with a derivative of either some renowned Argentinian like the 19th-century naturalist Florentino Ameghino – considered the father of Argentina’s vertebrate paleontology – or someplace in the Patagonia region, such as the Santa Cruz province or the town of El Calafate that straddles the shores of Lago Argentino.