Dr Mark Evans made the remarkable discovery merely by chance
The first dinosaur fossil from Antarctica has been found in a drawer after lying forgotten for 40 years.
The fossil was first unearthed in 1985 but remained tucked away in the geology collection at the British Antarctic Survey headquarters in Cambridge.
Now, palaeontologists have determined the bone is a tail vertebra from a Titanosaur, a group that included the most massive land animals in Earth's history.
The creature roamed Antarctica approximately 82 million years ago during the Late Cretaceous Period, when the now-frozen continent was blanketed in dense woodland rather than ice sheets.
The specimen was collected during an expedition to James Ross Island, with geologist Dr Mike Thomson meticulously recording the find in his field notebook on December 9, 1985.
His entry included a small sketch alongside a description noting it as the "vertebra of a large reptile" measuring roughly 10 centimetres across.
The original team suspected they had found remains of a marine reptile, leading them to place it in storage where it sat among thousands of other Antarctic specimens.
Dr Mark Evans, collections manager at BAS, stumbled upon the fossil while examining the extensive holdings gathered over decades of polar expeditions.
"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'," he said.
But Dr Evans immediately recognised the vertebra's distinctly dinosaur-like appearance.
To verify his suspicions, Evans enlisted help from Professor Paul Barrett at the Natural History Museum.
"Although it's not too much to look at, it actually has a really distinctive shape," Prof Barrett said, studying the specimen.
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The vertebra features a hollow at one end and a rounded protrusion at the other, creating the ball-and-socket joint arrangement characteristic of these dinosaurs.
"As soon as I saw it, I knew what we were dealing with it was a dead cert we were dealing with a Titanosaur," Prof Barrett added.
"This is a combination of features that's completely unique to these types of dinosaurs."
Scientists worldwide have now catalogued more than 100 Titanosaur species, all four-legged herbivores with elongated necks and counterbalancing tails.
The largest specimens exceeded 35 metres in length and weighed around 60 tonnes.
Based on this particular vertebra's dimensions, researchers have predicted the Antarctic dinosaur measured approximately seven metres long, suggesting either a juvenile animal or a smaller adult species.
During the Late Cretaceous Period, Antarctica bore no resemblance to the frozen wilderness we know today. Instead, it boasted luscious forests which provided abundant vegetation for plant-eating dinosaurs.
"It shows that an area that we now think is really uninhabitable was once actually very habitable and had this huge cast of characters living on it," the professor said.
Extremely few dinosaur fossils have emerged from Antarctica since 1985, with thick ice sheets concealing much of the continent's prehistoric record beneath the surface.
"It's helping us to work out how they fitted into these broader ecosystems at the very bottom of the world about 80 million years ago," Barrett added.