Arctic Fossil Abandoned in 1948 Turns Out to Be a Record-Size Triassic Predator

Nearly 80 years after a British expedition photographed a giant fossil on an Arctic island and left it to the icy winds, researchers have identified it as a new species — and a record-breaker. The creature, named Arctobatrachus urdensis, was a roughly 2.7-meter-long amphibian-like predator, making it by far the largest plagiosaurid ever discovered, scientists reported in Papers in Palaeontology.

A 70-Centimeter Skull With a Story

Plagiosaurids were flat-bodied, bottom-dwelling temnospondyls that lived during the Triassic period, with fossils known from Brazil to China. The Bjornoya (Bear Island) specimen was found in 1948, but the expedition could not carry it out; researchers assumed the harsh Arctic winters would destroy it. A Norwegian field party made a chance rediscovery in 1984, and using the 1948 photographs, scientists led by Rainer R. Schoch reconstructed the missing skull portions: 70 centimeters wide but only 21 centimeters long, a near-perfect semicircle armed with large teeth — the signature of an active hunter and likely top predator.

Phylogenetic analysis places Arctobatrachus among the earliest members of the plagiosaurid lineage, giving researchers a rare window into how these bizarre animals evolved: initially active swimmers with less flattened bodies, they later became more sedentary, flatter-bottomed forms. "The fossils have been discovered across the ancient world, but one discovered in 1948 would not be recovered until decades later," the authors note in the paper, which the University of Kansas and German scientists co-authored.