Scientists have stumbled on a rare dinosaur fossil from Antarctica, tucked away for decades in a drawer.

The bone comes from the tail of a long-necked, plant-eating dinosaur called a titanosaur. Scientists haven't yet identified the species it belongs to.

It was discovered in 1985 during an expedition to Antarctica's James Ross Island and collected by geologist Mike Thomson. Working with the British Antarctic Survey, Thomson was mapping the area's rock layers and collected marine reptile fossils to help with future dating efforts. He recorded the find as a large reptile.

Decades later, paleontologist Mark Evans spotted the bone in the British Antarctic Survey's collections and wondered whether it might be a dinosaur.

"It's only when you start thinking 'what's in this drawer,' that sometimes you come across something and you think, 'Ah, this looks interesting,'" Evans told BBC News.

He and other researchers analyzed the shape of the bone and compared it to other more complete dinosaur remains, confirming their discovery. The findings were published on Monday in the journal Acta Palaeontologica Polonica.

Dinosaur fossils are rare to find in Antarctica because of the unforgiving ice caps. But millions of years ago, when this dinosaur lived, the region was populated by lush forests — a "rather different and much more hospitable place than we think of today," said study co-author Paul Barrett with the Natural History Museum in London.

"This discovery represents only the second sauropod body fossil known from Antarctica, although it was the first dinosaur bone to be collected from the continent," the study's authors wrote.

Titanosaurs inhabited Antarctica 80 million years ago when it was covered in lush forest. Andrew McAfee, Carnegie Museum of Natural History

At about 23 feet long, the dinosaur was small for its group and may have been young when it died. Scientists don't know how the creature met its end, but they think its body floated away from the coast and sank to the sea floor, becoming fossilized in marine rock.

More than 100 species of titanosaur have now been identified around the world, according to the BBC. All of them are four-legged plant eaters, with very long necks that helped them reach up into trees and long counter-balancing tails. The biggest titanosaurs were more than 115 feet long and weighed about 60 tons.

Technology has come a long way since the dinosaur tail bone was first found, allowing researchers to peer inside bones and gain even more detailed information about ancient creatures. Thomson died in 2020 before the fossil was identified as belonging to a dinosaur.

"If he were still with us, he would be delighted to know what this was," Evans, a study co-author, said.

This image provided by the Natural History Museum shows a fossil found in Antarctica that belongs to a group of dinosaurs called titanosaurs.  Natural History Museum via AP

In:

• Antarctica
• Dinosaur