August 31 , 2016

by AMNH

In 2014, a rancher in the arid Patagonia region of Argentina stumbled upon a bone like none he’d ever seen before. He shared his discovery with the Museo Paleontológico Egidio Feruglio, which brought in paleontologist Dr. Diego Pol and colleagues to assess the extraordinary find.When they arrived at the site and began uncovering fossils, it became clear to Dr. Pol and team that they were looking at an unusually large animal. Dr. Pol, who received his Ph.D. degree in a joint program between Columbia University and the American Museum of Natural History in 2005, emailed a photo of an 8-foot femur, or thigh bone, to his mentor, Macaulay Curator of Paleontology Mark Norell.

By then, the paleontologists had inferred that this fantastic fossil was from an animal that belonged to a group known as the titanosaurs, a sub-group of the plant-eating dinosaurs known as sauropods. Now an arid desert, Patagonia was a lush, forested region millions of years ago, and home to numerous sauropod species. In recent years, sites there have begun surrendering these fossils at a shocking rate.

“We are finding these creatures in South America and Central Asia, places that are much less explored,” Pol said at the unveiling of The Titanosaur cast. “About half of the known titanosaur species come from South America, and the South American titanosaurs were the ones who achieved the largest body sizes.”

“If I was going to pick any place to go looking for [sauropods], I think where Diego and his team are looking would be a really good place,” added Norell.

The result was a bonanza of 223 titanosaur fossils. Though the remains are thought to represent as many as six individuals, more than 70 percent of the skeleton has been recovered, resulting in a remarkably complete fossil titanosaur. Still, the actual construction of The Titanosaur would happen thousands of miles north, in Ontario, Canada.

RCI is in business because ancient bones, even huge ones, are fragile things, and original fossils are often kept in storage after being excavated. The Museum’s fourth floor halls do present real fossils—85 percent of the specimens on display are the originals, in fact. But some of the larger mounts visitors see, like the Barosaurus in the Theodore Roosevelt Rotunda, are casts because the real fossils would be much too heavy to mount.

Even for a company that specializes in building life-size replicas of some of nature’s most notable behemoths—RCI also created the Museum’s Barosaurus in 1991—The Titanosaur was a big job.

Before the fossils were removed from the site, RCI digitally scanned each piece, producing a set of 3D blueprints for creating a replica of a titanosaur skeleton—though of course, paleontologists would need to infer some of the “missing pieces” by looking at closely related species.

Back in RCI’s Ontario workshop, industrial 3D cutters shaped Styrofoam into models of the bones, which were then used to make rubber molds that were filled with fiberglass resin. Once the resin hardened, it was removed from the molds, handcrafted to the precise measurements of the fossil excavated in Argentina, and mounted on steel support beams in a pose specified by Pol and Norell.

Like so many globe-trotting trips, The Titanosaur’s journey came to a close in New York City. The completed cast arrived at the Museum in 45 separate pieces, some of them so large they were barely squeezed into the building. Then, the fiberglass casts on steel beams were joined together in a massive cast—a feat of construction that was completed inside of a week.

The new addition to the Museum’s fossil floors is so huge, it barely fits in its new home: at 19-feet-high, the cast grazes the ceiling of the Wallach Orientation Center, and at 122 feet long, it doesn’t quite fit inside the space, poking its head out in a friendly welcome toward the staircase. What’s perhaps most astonishing is that the animal hadn’t yet reached its full size when it died—it was a juvenile, as scientists learned from analyzing the fossils. Some of those original fossils are now on display nearby, on loan from the Museo Paleontológico Egidio Feruglio.

“There’s nothing like finding a great new fossil, especially a big one like this one,” said the Museum’s Provost of Science Mike Novacek. “The Titanosaur itself is ancient, but it nevertheless embodies and reflects the very modern, dynamic, and thrilling state of paleontology today.”

Generous support for The Titanosaur exhibit has been provided by the Susan S. and Kenneth L. Wallach Foundation.

A version of this story originally appeared in the Summer 2016 issue of the Member magazine Rotunda.