By Will Dunham
WASHINGTON (Reuters) - Paleontologists are restoring the good name of Brontosaurus more than a century after it was deemed scientifically invalid and the famous dinosaur was reclassified as another genus called Apatosaurus.
They unveiled on Tuesday an exhaustive analysis of Brontosaurus remains, first unearthed in the 1870s, and those of closely related dinosaurs, determining that the immense, long-necked plant-eater was not an Apatosaurus and deserved its old name back.
Paleontologist Emanuel Tschopp of Portugal's Universidade Nova de Lisboa cited important anatomical differences including Apatosaurus possessing a wider neck than Brontosaurus and being even more massively built.
"The differences between Apatosaurus and Brontosaurus are numerous enough to revive Brontosaurus as a separate genus from Apatosaurus," Tschopp said.
Brontosaurus, which lived in North America around 150 million years ago in the Jurassic Period, was about 72 feet (22 meters) long and weighed about 40 tons.
"Brontosaurus and T. rex are the two most popular dinosaur names ever," said Universidade Nova de Lisboa paleontologist Octávio Mateus. "Even 112 years after paleontologists considered it invalid, the name Brontosaurus still echoes in the popular culture. It was indeed a very cool dinosaur name."
"This will be like recovering Pluto as a planet again," Mateus added, referring to astronomers' 2006 decision to downgrade Pluto from a full-fledged planet to a dwarf planet.
After his team excavated fossils of two huge long-necked dinosaurs, prolific 19th century paleontologist Othniel Charles Marsh named the first one Apatosaurus ("deceptive lizard") in 1877 and the second one Brontosaurus ("thunder lizard") in 1879.
In 1903, paleontologist Elmer Riggs declared that Brontosaurus and Apatosaurus were too similar for each to be considered a separate genus. Because Apatosaurus was named first, under the rules of scientific naming it supplanted Brontosaurus.
But the name was so popular it survived its burial, with "Brontosaurus" and things like "Bronto Burgers" appearing in numerous books, cartoons, movies and elsewhere.
Brontosaurus belonged to a group of dinosaurs with long necks and tails and pillar-like legs called sauropods that included Earth's largest land animals ever.
This study, published in the scientific journal PeerJ, focused on the anatomy and relationships among a category of sauropods called diplodocids, which includes Brontosaurus, Apatosaurus, Diplodocus and others.
"I remember finding out that Brontosaurus was actually called Apatosaurus as a child," University of Oxford paleontologist Roger Benson said. "It didn't seem right, and I think a lot of people will secretly be pleased that Bronto is back again."
(Reporting by Will Dunham; Editing by Sandra Maler)