In 1948, scientists abandoned this giant fossil. Nearly 80 years later, it became something nobody expected

Nearly eight decades after a British expedition first documented the battered remains of a giant fossil on an Arctic island, scientists have identified it as a previously unknown species of ancient amphibian-like creature. The fossil, discovered on Bjørnøya, or Bear Island, has been named Arctobatrachus urdensis and is the largest plagiosaurid ever found, according to a Times of India report, citing Phys.org.

The animal measured around 2.7 metres (8.9 feet) in length, making it a giant among the extinct group of flat-bodied, bottom-dwelling creatures that lived during the Triassic period, roughly 251 to 201 million years ago.

A fossil forgotten in Arctic, lost for decades

The creature's fossil was first discovered in 1948, when members of a British expedition photographed the remains, collected some of the bones and left the rest at the site because of its remote Arctic location.


Scientists initially assumed that the exposed fossil would not survive the region's harsh weather. It was not seen again until 1984, when a Norwegian field expedition unexpectedly rediscovered it.

By then, decades of exposure to wind, rain and freezing conditions had taken a heavy toll. The fossil had developed numerous cracks and had lost several bones. After a week-long excavation, researchers managed to recover the remains, but the specimen remained largely unexamined for several more decades.

It was eventually prepared at the State Museum of Natural History Stuttgart, allowing scientists to conduct a detailed study.

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A strangely shaped ancient predator

Plagiosaurids were extinct temnospondyl amphibians that lived in aquatic environments during the Triassic period. Their unusual appearance was characterised by flattened bodies and extremely broad skulls.

“The skull was much wider than long, and its outline resembles a boomerang,” paleontologist Rainer Schoch of the State Museum of Natural History Stuttgart said, according to Phys.org.

The study, titled A giant plagiosaurid temnospondyl from Bjørnøya (Svalbard, Norway) and the origin of the plagiosaurid body plan, suggests that these animals inhabited the bottoms of rivers, lakes and seas. They likely waited for prey to approach before using their wide mouths to suck it in.

Plagiosaurid fossils have been found in several parts of the ancient world, including present-day Brazil and China. However, the Bjørnøya specimen stood out because of both its size and its distinctive anatomical features.

Skull nearly 70 cm wide

Using photographs taken during the original 1948 expedition, researchers were able to reconstruct parts of the skull that were missing from the recovered fossil.

The skull measured approximately 70 cm (27.6 inches) across but was only about 21 cm (8.3 inches) long. Its extraordinary width gave it an almost semicircular shape.

Its large size, prominent teeth and exceptionally broad mouth indicate that Arctobatrachus urdensis may have been an active predator and potentially occupied a high position in the Triassic aquatic food chain.

Scientists also found that several of its anatomical characteristics did not match those of previously known plagiosaurids, leading them to classify the fossil as a new species.

Clues to the evolution of plagiosaurids

The researchers' analysis of the animal's evolutionary position suggests that Arctobatrachus urdensis was among the earliest members of the plagiosaurid lineage.

That makes the fossil particularly significant because it provides clues about how the group evolved. According to the study, the earliest plagiosaurids appear to have been more active swimmers with less flattened bodies. Over time, the lineage evolved towards the highly flattened and more sedentary body form seen in later members of the group.

The discovery therefore offers researchers a rare glimpse into an early stage in the evolution of these unusual aquatic animals.

A window into the Triassic world

The researchers say fossils such as this one can help reconstruct what Earth looked like hundreds of millions of years ago, including its climate, ecosystems and the animals that inhabited them.

“Many people are fascinated by our past,” Schoch said, according to Phys.org. “What did the planet, its climate and life look like, say 240 million years ago?”

The giant fossil from Bjørnøya provides another piece of that picture, revealing an unusually large and previously unknown predator that lived in Earth's ancient waters more than 200 million years ago.

(With inputs from TOI)