For anyone who has ever been told by a smarty-pants 7-year-old, “There’s no such thing as Brontosaurus; it’s called Apatosaurus” — it is payback time.  “We have good evidence now for the resurrection of Brontosaurus,” Emanuel Tschopp, a paleontologist with the New University of Lisbon, said on Tuesday.  He was referring to the name, not to the creature itself, of course, and to an exhaustive study of 80 or so fossils in a group of long-necked giants called the Diplodocidae, familiar from natural history museums the world over. These plant-eaters grew to lengths of more than 100 feet and weighed thousands of pounds, and it is thought they could crack their long tails like bullwhips, creating sonic booms to scare away predators.  The name Brontosaurus was first used in the late 1800s to describe fossils of a dinosaur now on display at the Yale Peabody Museum, but by 1905 it had been reclassified as Apatosaurus, because it was so similar to another sauropod dinosaur of that name.  Dr. Tschopp and his colleagues Octávio Mateus at the New University and Roger B. J. Benson at the University of Oxford in England decided that although Brontosaurus and Apatosaurus are similar, there are actually two different genera and the Yale specimen is really a Brontosaurus after all. So are several other museum specimens, they said, including one at the University of Wyoming, and a baby Apatosaurus at the Carnegie Museum of Natural History in Pittsburgh.  Their paper, released online on Tuesday in the journal PeerJ, with all of its nearly 300 pages freely available to anyone, will not be the last word on whether the Brontosaurus name should come back into scientific use. Names of species and genera are matters of expert opinion. There is no national or international board of official dinosaur names that decides who is right.  “What’s interesting to me is that Brontosaurus and Apatosaurus are still extremely close,” said Matthew T. Carrano, a curator at the Smithsonian Institution’s National Museum of Natural History. “This provides a lot of new information for the argument, but the argument will continue.”  Dr. Tschopp and his colleagues looked at 477 distinct traits that could be identified on the fossil bones and then analyzed them in several ways to look for differences.  Dr. Benson said they set a standard based on the differences between two well-known species of similar long-necked dinosaurs, Diplodocus and Barosaurus. “Brontosaurus is at least as different from Apatosaurus as Diplodocus is from Barosaurus,” he said.  Dr. Benson pointed out that “the names are just handles” that help scientists study how life evolves into different forms.  Most of the differences are highly technical and noticeable only to anatomists, said Dr. Tschopp. To pick one understandable example, he said, “Apatosaurus has a relatively wider neck than Brontosaurus.” But it is the number of differences that is important, he said.  Jeffrey A. Wilson, a paleontologist at the University of Michigan, said that he did not have a position on whether the name should be resurrected but that he found the criteria for distinguishing between Apatosaurus and Brontosaurus arbitrary.  It was a matter of judgment that involved deciding how different was different enough to justify two distinct genera. “It’s as if they had a pizza,” he said, and “cut it in six pieces.” Why not cut it into four pieces? he asked.  The name game is played not only by scientists. There are pitfalls for parents and children doing their obligatory museum visits. The Apatosaurus on display at the American Museum of Natural History is probably still an Apatosaurus, said Dr. Tschopp, as is the adult skeleton at the Carnegie Museum.  In the end, it may be too complicated for parents to remember which is which. So the 7-year-olds may continue to rule.  A version of this article appears in print on April 8, 2015, on page A4 of the New York edition with the headline: A Prehistoric Giant Is Resurrected, if Only in Name. Order Reprints| Today's Paper|Subscribe
A team of European scientists said it has identified enough unique anatomical details to distinguish the Brontosaurus from the Apatosaurus.