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From left, Vanessa Rhue, collections manager in vertebrate paleontology, Susan Butts, senior collections manager in invertebrate paleontology, and Advait Jukar, curatorial affiliate in vertebrate paleontology, discuss the positioning of bones for a one-twelfth scale model of the Brontosaurus previously exhibited in the Great Hall of the Yale Peabody Museum of Natural History in New Haven on May 4, 2022.

From left, Vanessa Rhue, collections manager in vertebrate paleontology, Susan Butts, senior collections manager in invertebrate paleontology, and Advait Jukar, curatorial affiliate in vertebrate paleontology, are photographed with a one-twelfth scale model of the Brontosaurus previously exhibited in the Great Hall of the Yale Peabody Museum of Natural History in New Haven on May 4, 2022.

Scale models of a Tylosaurus chasing an Archelon photographed in Yale University’s Kline Geology Laboratory in New Haven on May 4, 2022. The Archelon was previously exhibited in the Great Hall of the Peabody Museum of Natural History. The Tylosaurus is a new aquisition.

NEW HAVEN — When you’re deciding how a Brontosaurus is going to look after it’s been taken apart, cleaned, repaired and put back together, you have to start small.

Brontosaurus, a star of the Yale Peabody Museum of Natural History, and its many fossil and mammal associates are up in Trenton, Ontario, at Research Casting International, each femur and vertebra carefully conserved.

Meanwhile, scale models of the fossils have been sent to the Peabody so the museum’s paleontologists can manipulate and correct the poses so they will more accurately reflect what modern science says the creatures looked like.

For example, Brontosaurus’ head will tilt in a more bird-like fashion, staring at visitors as they enter the Great Hall when the museum reopens in 2024.

First, though, RCI’s experts in fossil restoration and conservation “remove the plaster and the paint that had been obscuring a lot of the bone, but also the old armature, the metal framework that’s used to create the pose for the mount,” said Vanessa Rhue, collections manager in vertebrate paleontology at the Peabody.

“Then they can actually stabilize each individual bone, because fossils, inherently, they’re not always very stable,” Rhue said. “And when they’re large and heavy, under their own weight, they can suffer damage over time.”

“An individual vertebra from this animal would be about as big as this table,” said Advait Jukar, curatorial affiliate in vertebrate paleontology at the Peabody.

When all the bones were ready, a one-twelfth-scale model of Brontosaurus was created using light-scanning technology, such as an Artec Space Spider, and 3D printing.

The Space Spider “uses light to capture the three-dimensional image and from that you can generate an OBJ file and 3D print something in real time, and you can also adjust the size at which you print it, so you can scale something down or scale something up,” Rhue said.

Much like a JPG file contains a photo, an OBJ file is a 3D image format that can be read by 3D image-editing software.

Now, the Peabody’s paleontologists are shifting and turning the model’s bones to make it look the way the dinosaur will.

“First of all, the tail is off the ground,” said Susan Butts, senior collections manager in vertebrate paleontology. “We will add a lot of vertebrae to the tail. We’ve made a lot of really small adjustments like to how much the toes spread.”

The toes “were closer together so they’re a bit more splayed, but they’re also more forward facing,” said Vanessa Rhue, collections manager in vertebrate paleontology.

The tail actually will be about three times as long, with 72 vertebrae, called caudals, Jukar said. Now, it only has 12. In the model, a wire shows how much longer the tail will be, flying behind, as if the Brontosaurus were running. The dinosaur will be about 75 feet long, Rhue said.

The new pose “is based on other known specimens that have been collected,” Rhue said. “So when you have the opportunity to do a remount it allows you to revisit the pose in light of new research, in light of new specimens that have since been found, and revise your interpretation of how it would have mechanically been able to move its body.” Rhue said more vertebrae also will be added to Brontosaurus’ neck

Rhue said Chief Curator Jacques Gauthier decided “to place the head in such a position that it doesn’t look like a mammal but reflects the posture of a bird, which is a bit inquisitive looking, has its eye turned toward the visitor. As new guests will be entering the hall, they’ll be greeted firstly by the Brontosaurus.”

“They’ll be eyed by it,” Butts said. That makes sense because birds are considered direct descendants of dinosaurs.

As they decide how different parts of the skeleton will look, such as the articulation, or bend, of the tail, “you have to look at different features of the vertebrae to see that they can actually move together properly,” Butts said.

“The advantage of printing a model of this size at this particular scale gives you the opportunity to see how minor adjustments, while they may seem small, actually reflect a pretty large change in the overall posture of the mount, which has ramifications for how it can fit within a space,” Rhue said. A decision to have the tail whip around “has ramifications for the rest of the skeleton” and may not be desirable for the pose as a whole, she said.

Before the models were put together, there were meetings held to discuss what the Peabody staff wanted. “So we’re starting already from a place of informed changes,” Butts said. “And building on top of that to sort of give it character and make it realistic and make it not look like a static skeleton in a room and make it look like there’s a dinosaur in the room with you. Give it renewed life.”

Two other skeletons aren’t dinosaurs but will be highly visible in the new Central Gallery. One is Archelon, the giant sea turtle with the missing right hind leg. It will be chased in midair by Tylosaurus, a predatory marine reptile, one of whose relatives could have bitten off Archelon’s flipper.

While Archelon was in the Great Hall since it was built almost 100 years ago, it will be posed with its front flippers up, “sort of soaring,” Butts said.

Studying how the Archelon’s leg healed, a field known as paleopathology, “we can then infer from that that the injury was not the cause of death, but the organism was able to live with that for some period of time,” Rhue said.

“And so in this pose, we’re trying to reenact a very plausible moment in time where this particular specimen was escaping predation,” she said.

Tylosaurus, a large mosasaur, is “related to pythons and monitor lizards,” Jukar said. “And pythons have this extra set of jaws on their upper palate, which helps them pull their prey into their mouths as they feed.” So does the Tylosaurus.

“These are from what’s called the Western Interior Seaway,” Butts said. “And this is this shallow waterway that covered the Great Plains from about 100 to 65 million years ago,” the Late Cretaceous Period, when the dinosaurs began to die off. “So it went all the way from Canada down to Mexico,” she said.

Unlike Archelon, “The Tylosaur is a new acquisition for the Peabody, meaning it’s a new specimen added to our collections that we’re putting on display for the first time,” Rhue said. It was purchased from Triebold Paleontology in Colorado. Most of the exhibits, however, are from the Peabody’s collections.

“One of the things that you might notice about Tylosaurus is that there’s a bend in the tail,” Jukar said. The bend is caused by a vertical tail fluke, he said. Whales, on the other hand, have two horizontal forked flukes at the end of their tails.

All of the decisions about how each mount will be posed were reached after hours of discussions, preserved on film. Once the final tweaks are finished, scans will be sent back to RCI.

“We would spend an hour-and-a-half posing Brontosaurus,” Butts said. “And then Vanessa would take 1,000 pictures of it from every angle, because they don’t remain stable very well. They’re designed to be molded and moved in little bits. So she’s fully documented the exact position that we agreed on, after all this discussion.”

It’s important to get everything right, said Christopher Renton, a Peabody spokesman, because Brontosaurus could stand unchanged for 90 years, just as it had when it was first mounted before. It’s especially important for the Brontosaurus and Archelon, which are holotypes.

“The holotype is the name-bearing specimen that’s used to describe a new species in science, and it becomes the standard of comparison for any new material that is found,” Rhue said. “And this opportunity poises us to reflect back on other specimens that have been collected since this was described initially.”

Brontosaurus was first described in 1879 after it was found in Como Bluffs, Wyo. In 2003, after a century of paleontological argument, it was decided it was actually an Apatasaurus. Finally, in 2015, its original name was restored. “Brontosaurus is back!” exclaimed Gauthier at the time.

The dinosaur also has had two heads, since it was found without one. The original, hulking cast head was put on display in the Great Hall after a more angular head was installed, based on new discoveries.

“It’s important we get it right when it’s the world’s first one like this is,” Renton said. “This is ‘the’ Brontosaurus, so we want to make sure when people see it that it’s positioned correctly.”

Ultimately, Rhue said, “The purpose of our collections are for research. And exhibits are really another storage location from a collections perspective. The research will be ongoing for the things that are on display.”

Speaking of storage, what will be on display at the Peabody is a minuscule part of the museum’s 14 million items, Butts said.

The 3D scans also will be invaluable to research, because “sometimes when things are on exhibit, it can obscure the view to the observer of key morphological or surface features, anatomical features,” Rhue said. “The shape of bones is important to paleontologists. It’s something we can quantify and measure and compare and contrast.”

Having the skeletons taken apart — disarticulated — “allows increased accessibility to the specimens for research and by scientists across the world who may not have to physically travel here to be able to study the specimen and include it in their research,” she said.

edward.stannard@hearstmediact.com; 203-680-9382

Ed Stannard is a reporter whose beats include Yale University, religion, transportation, medicine, science and the environment. He grew up in the New Haven area and has lived there most of his life. He received his journalism degree from Northwestern University's Medill School of Journalism and earned a master's degree in religious studies from Sacred Heart University. He has been an editor at the New Haven Register and at the Episcopal Church's national newspaper.

He loves the arts, travel and reading.