A rare dinosaur fossil from Antarctica is found tucked away in a drawer

A rare dinosaur fossil from Antarctica is found tucked away in a drawer

For 40 years, a specimen sat forgotten in a geology collection drawer in Cambridge. Recent analysis by paleontologists has revealed the bone to be a rare find: the first dinosaur fossil ever discovered in Antarctica.

The fossil is a tail vertebra from a titanosaur, a group of long-necked, plant-eating dinosaurs that included some of the largest animals to ever walk the Earth. While researchers have confirmed the group, they have not yet identified the specific species.

The bone was originally collected in 1985 by geologist Mike Thomson during an expedition to James Ross Island. Working with the British Antarctic Survey (BAS), Thomson was mapping rock layers and collecting marine reptile fossils to assist with future dating. At the time, he recorded the find as a large reptile.

The specimen remained in the BAS collections until paleontologist Mark Evans, who manages the geological collections and labs at the BAS, spotted the bone a few years ago. Evans suspected the bone was a dinosaur and later identified it as a titanosaur tail vertebra after comparing it to other complete dinosaur remains.

The fossil is the only one from the continent found in the Santa Marta Formation, a rock layer dating back to the Late Cretaceous about 82 million years ago.

While the largest of the group, such as Patagotitan mayorum, could reach 121 feet (36m) in length and weigh 65 tonnes, this specimen is estimated at 19 to 23 feet (six to seven metres). Researchers believe the animal was either a dwarf species or a juvenile when it died.

The circumstances of its death remain unknown, but scientists believe the carcass floated away from the coast and sank to the sea floor, where it became fossilized in marine rock.

Finding dinosaur remains in Antarctica is exceptionally difficult because most of the land is buried under thick ice caps. Most discoveries are limited to the Antarctic Peninsula and its adjacent islands, or the Transantarctic Mountain range, where rock is exposed along shorelines.

The find provides critical evidence regarding the movement of dinosaurs across southern continents. Titanosaurs have not been found in Australia, and evidence in New Zealand is limited. The presence of the animal in Antarctica suggests they likely traveled across these connected areas of the former southern supercontinent, Gondwana.

Despite its current climate, the region was once a rather different and much more hospitable place than we think of today, according to study co-author Paul Barrett of the Natural History Museum in London. Heavy volcanic activity contributing CO2 to the atmosphere kept the region warm, supporting lush temperate forests that provided food for large herbivores.

Matthew Lamanna of the Carnegie Museum of Natural History noted that the specimen is a reminder of why museums steward such objects, as new expertise and methods allow scientists to unlock discoveries from specimens that have been waiting in plain sight.

Mike Thomson passed away in 2020.

"If he were still with us, he would be delighted to know what this was,"

Mark Evans, study co-author, via AP

The findings were published Monday, in the journal Acta Palaeontologica Polonica. Paul Barrett suggests that as climate change causes ice to retreat, further evidence of this prehistoric biodiversity may be uncovered on the continent.