What’s old, long, and green? Meet Gnatalie, Los Angeles’ new dinosaur.

The latest dinosaur being mounted at the Natural History Museum in Los Angeles is not only a member of a new species – it’s also the only one found on the planet whose bones are green, according to museum officials.

Named “Gnatalie” (pronounced Natalie) for the gnats that swarmed during the excavation, the long-necked, long-tailed herbivorous dinosaur’s fossils got their unique coloration, a dark mottled olive green, from the mineral celadonite during the fossilization process.

While fossils are typically brown from silica or black from iron minerals, green is rare because celadonite forms in volcanic or hydrothermal conditions that typically destroy buried bones. The celadonite entered the fossils when volcanic activity around 50 million to 80 million years ago made it hot enough to replace a previous mineral.

The dinosaur lived 150 million years ago in the late Jurassic Era, making it older than the Tyrannosaurus rex – which lived 66 million to 68 million years ago.

Researchers discovered the bones in 2007 in the Badlands of Utah.

“Dinosaurs are a great vehicle for teaching our visitors about the nature of science, and what better than a green, almost 80-foot-long dinosaur to engage them in the process of scientific discovery and make them reflect on the wonders of the world we live in!” Luis M. Chiappe of the museum’s Dinosaur Institute said in a statement about his team’s discovery.

Matt Wedel, anatomist and paleontologist at Western University of Health Sciences in Pomona near Los Angeles, said he heard “rumors of a green dinosaur way back when I was in graduate school.”

When he glimpsed the bones while they were still being cleaned, he said they were “not like anything else that I’ve ever seen.”

The dinosaur is similar to a sauropod species called Diplodocus, and the discovery will be published in a scientific paper next year. The sauropod, referring to a family of massive herbivores that includes the Brontosaurus and Brachiosaurus, will be the biggest dinosaur at the museum and can be seen this fall in its new welcome center.

John Whitlock, who teaches at Mount Aloysius College, a private Catholic college in Cresson, Pennsylvania, and researches sauropods, said it was exciting to have such a complete skeleton to help fill in the blanks for specimens that are less complete.

“It’s tremendously huge, it really adds to our ability to understand both taxonomic diversity ... but also anatomical diversity,” Mr. Whitlock said.

The dinosaur was named “Gnatalie” last month after the museum asked for a public vote on five choices that included Verdi, a derivative of the Latin word for green; Olive, after the small green fruit symbolizing peace, joy, and strength in many cultures; Esme, short for Esmeralda, which is Spanish for Emerald; and Sage, a green and iconic L.A. plant also grown in the Natural History Museum’s Nature Gardens.

This story was reported by The Associated Press.