What is big, green and 150 million years old? Meet dinosaur skeleton 'Gnatalie.'

A gigantic dinosaur twice the size of a city bus will soon be on display for the public to see – its one-of-a-kind green bones and all.

The team of paleontologists who discovered, recovered and assembled the 150-million-year-old bones from a remote site in Utah believe the find is the most complete long-necked dinosaur skeleton on the west coast. Nicknamed "Gnatalie" for the stinging gnats that pestered excavators during digs, the fossils are also believed to be evidence of a new prehistoric herbivorous species.

The more-than 75-foot-long skeleton, distinct for not only its size, but its dark-green bones, is soon to be mounted and displayed at the Natural History Museum in Los Angeles .

Here's what to know about Gnatalie, why it has green bones and how to see the massive skeleton later this year.

Bones of Gnatalie discovered in Utah

The fossils of Gnatalie were discovered in 2007 in the Badlands of Utah.

Soon after, National Geographic began documenting the painstaking excavation and reconstruction in collaboration with the Natural History Museum's Dinosaur Institute, which became the subject of the magazine's September issue .

While sifting through the dinosaur parts buried in tons of rock, the team realized that Gnatalie was no ordinary dinosaur – at least, not one yet known to humankind.

The dinosaur that paleontologists eventually brought back to life is composed of multiple individuals of a gigantic herbivore belonging to a sauropod species similar to Diplodocus . The Brontosaurus and Brachiosaurus are perhaps the most famous of the sauropods, dinosaurs defined by their long necks, long tails, small heads and four pillar-like legs.

Scientists believe this sauropod skeleton may be a new species of dinosaur altogether.

Why is the dinosaur green-boned?

The dinosaur lived 150 million years ago in the late Jurassic period, making it millions of years older than the terrifying Tyrannosaurus rex that roamed the Earth some 66 million to 68 million years ago .

The fossils that make up Gnatalie were from several of the dinosaurs buried in a riverbed, preserved during the fossilization process by the green mineral celadonite.

Scientists have deduced that rare volcanic activity around 80 to 50 million years ago made it hot enough for this new green mineral to replace an earlier mineral – giving Gnatalie the unusual green coloring.

How to see Gnatalie at LA museum

Those interested in seeing this unique green dinosaur have their chance this fall.

Gnatalie is slated to be displayed as early as November in the Natural History Museum's new welcome center, meaning guests don't even need to purchase a ticket to see the dinosaur.

Dr. Luis Chiappe, senior vice president for research and collections at the museum, helped to lead the research and reconstruction of Gnatalie.

"Dinosaurs are a great vehicle for teaching our visitors about the nature of science," Chiappe said in a statement. "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."

Eric Lagatta covers breaking and trending news for USA TODAY. Reach him at elagatta@gannett.com

This article originally appeared on USA TODAY: What is big, green and 150 million years old? Meet dinosaur skeleton 'Gnatalie.'