The Brontosaurus is back.

On Tuesday at the Yale Peabody Museum of Natural History, three-year-old Jessica Dinan learned to pronounce the name of the massive dinosaur skeleton in front of her. Unlike the thousands of children who had frequented the museum before her, she will refer to the specimen by its proper name — the Brontosaurus.

On April 7, paleontologist Emanuel Tschopp, a postdoctoral researcher at the Universidade Nova de Lisboa in Portugal, released a 298-page paper explaining that, contrary to past scientific consensus, the Apatosaurus and Brontosaurus are of different genera. Just a week after the paper’s release, the Peabody was the world’s first museum to hold a renaming ceremony for their own Brontosaurus skeleton, the single most complete specimen of any Apatosaurus or Brontosaurus currently known.

“Finally, we are able to return Brontosaurus to its rightful name,” said David Heiser, head of outreach at the Peabody, pointing to the over-60-foot skeleton above him. “People who walk into this room drop to their knees.”

Although the Brontosaurus is a worldwide paleontological fascination, the history of the Brontosaurus is closely tied with the Peabody itself.

In the late 1800s, Yale professor and Peabody curator O.C. Marsh, who was the nephew of the museum’s namesake, George Peabody, analyzed and named the bones of both the Apatosaurus and Brontosaurus. But in 1903, paleontologist Elmer Riggs proposed that the specimen classified separately as Apatosaurus was really a young Brontosaurus. In other words, they were the same animal. Because the Apatosaurus had been discovered first, its name was kept, and the name Brontosaurus was discarded. The renaming ceremony brings back the once-discarded name.

While it took Peabody curators nearly a century to change the label from Brontosaurus — which means “Thunder Lizard” — to Apatosaurus after the first name change in 1903, it took just days, once the most recent study was published, to change the label back to its original title, said Jacques Gauthier, curator of vertebrate paleontology at the Peabody and professor of geology and geophysics.

“Having the original Brontosaurus skeleton, we wanted to be the first museum to rename it,” said Richard Kissel, director of public programs at the Peabody. “Brontosaurus was named at Yale. We wanted to bring back the name at Yale. We didn’t want any other museum to beat us.”

A day after the paper was released, Kissel and other Peabody staff formed a small team to pull off the renaming event quickly. Kissel said he is unsure whether other museums with Brontosauri will follow suit. More research will likely be conducted on the topic, he said, adding that the most recent paper’s hypothesis is “re-rewriting the book on dinosaurs.”

The large specimen is actually a mix between the two genera. Because researchers believed that the Brontosaurus and Apatosaurus were the same animal, the head is that of an Apatosaurus and the bottom that of a Brontosaurus, making the skeleton a combination of two animals.

According to Kissel, there are currently no existing Brontosaurus skulls in good condition. The Apatosaurus head then will remain for the time being until the discovery of a full Brontosaurus skull, he added.

At the ceremony, Gauthier also mentioned the Peabody’s plans for renovating the home of the Brontosaurus, the Great Hall of Dinosaurs. Those plans have been in the works for the past several years.

With the upcoming renovation, curators will correct some inaccuracies in the skeleton by adding a few bones to the neck and raising the tail above the ground, which paleontological research suggests would have been the actual position of the tail. The skeletons will also interact with one another in “dynamic and modern pose[s],” Gauthier said.

The museum still needs to raise the money, though. The remounting of the Brontosaurus alone will cost $1.8 million, Gauthier said.

Nearly 200 guests, young and old, were in attendance. Victoria DePalma, whose father was responsible for helping to mount the skeleton in the 1930s, has considered the specimen to be her “dinosaur since the day [she] was born.” She added that she was delighted to see the number of people who came to celebrate the renaming, an indicator to her of how many lives her father’s constructed dinosaur has touched. DePalma has established a gift annuity to help fund the Great Hall renovation project.

According to David Heiser, head of education and outreach at the Peabody, the Peabody Brontosaurus has been seen by more than two million school children and 10 million museum visitors.

The label unveiling ceremony was strategically placed on Family Day at the Peabody, Kissel said. Along with cake and a rendition of “Happy Birthday,” families and children partook in activities and arts and crafts related to museum programming. The naming ceremony concluded with a slideshow about the history of the Brontosaurus and a recording of the song “Dinosaur Stomp.”

“The Land Before Time,” the animated film about dinosaurs that was released in 1988 when the Brontosaurus was no longer considered a separate genus, still features the Brontosaurus in the character Little Foot, whose mother dies in the first five minutes of the first installation.