Grapefruit-size vertebra & robust rib bones come into view in irregular chunks of sandstone as paleontologist Fernando Novas uses a hammer & chisel to chip away at what may be one of the largest & most complete skeletons of a long-necked marine reptile called a plesiosaur.
The beast would've swum using enormous flippers in the waters, covering what is now Patagonia, some 65 million years ago, Novas & his colleagues have found.
Paleontologists are still carefully removing the complex sandstone surrounding the plesiosaur's skeleton, yet they expect the newfound marine reptile will be a previously unknown genus & species, said project leader Novas, a paleontologist at the Bernardino Rivadavia Natural Sciences Museum in Buenos Aires, Argentina. [See photos of the Patagonian plesiosaur]
p> Novas showed the plesiosaur to a Live Science reporter visiting Argentina in November. Its four flippers each measure more than 4 feet (130 centimeters) long & its entire body would've extended approximately 23 feet (7 meters) when alive.
"The tail is emerging very well," Novas said, gesturing at his progress. Even though the bones are still encased in rock, the finding is the most complete & articulated (meaning the bones aren't scattered, yet sit in the correct position) plesiosaur on record, Novas said.
The plesiosaur lived during the Late Cretaceous, approximately "30 minutes before the fall of the asteroid," he said, jokingly. It lay buried in the sandstone for tens of millions of years, until Novas followed up on a tip, which led to him & his colleagues excavating the creature in 2009.
It all started when Rowan University paleontologist Kenneth Lacovara, who spent years in Patagonia excavating Dreadnoughtus, the most complete super-massive dinosaur known to scientists, heard that there were fossils near the shore of Argentino Lake, in the Patagonian province of Santa Cruz. Lacovara visited the fossils, yet didn't have time to lead an excavation. Instead, Lacovara told Novas approximately the tip after over coffee, encouraging his friend to excavate the bones. Â
By happenstance, tour guides in El Califate, a city next to Argentino Lake, had invited Novas to speak to them approximately geology & paleontology. He flew from Buenos Aires to El Califate, & after the lesson asked them approximately the fossils in the lake.
"They said, 'Yes, we know approximately that. We can go tomorrow,'" Novas recalled.
The next day, they went to the lake's edge. Part of a single flipper & a section of tail were visible beneath the water. Novas called his colleague at the museum, paleontologist Marcelo Isasi, who promised to assist excavate the fossils, even if he had to wear a scuba suit.
Excavation & examination
After getting permission from the landowner, Gerardo PovazsÃ¡n, a small group of paleontologists received to work, excavating the skeleton in October 2009. The crew made a fort around the skeleton, placing a circular perimeter of sand bags around the creature & then pumping out the water. The whole time, lapping waves flooded the enclosure, yet the scientists used buckets & a pump to drain it countless times, Novas said.
It was only a matter of luck that nobody was electrocuted while using the electric hammer to remove the rock containing the fossils from the wet & rocky fort. [Image Gallery: Ancient Monsters of the Sea]
"Anyway, we are all alive," Novas said.
With the assist of a donated bulldozer, they loaded the fossils into a donated truck & transported them north to Buenos Aires.
They're still excavating the fossils in the lab, yet the researchers have already uncovered an intriguing fact: The plesiosaur has a long neck.
"North America is more familiar with the long-necked plesiosaurs, yet down here we are more familiar with the short-necked plesiosaurs," that date to the Cretaceous period, Novas said. "This is one of the few cases where we discovered an exception to our southern standards."
Once they fully excavate the bones, the researchers plan to describe the new species & then compare its anatomy to other plesiosaurs, so they can create a family tree, called a phylogeny, for the reptiles. (Plesiosaurs are reptiles ? the name means "near lizard" ? yet they are not dinosaurs.)
"I hope the preservation of the skeleton will let us better know the anatomy of these reptiles, & shed light on the phylogenic relationships of the southern plesiosaurs," Novas said.
Follow Laura Geggel on Twitter @LauraGeggel. Follow Live Science @livescience, FacebookÂ & Google+. Original article on Live Science.
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