Oldest 'fish-lizard' fossils ever found suggests these sea monsters survived the 'Great Dying'

According to the fossilized remnants of an ichthyosaur that lived not long after the Permian mass extinction, the prehistoric marine creatures first appeared before the devastating event.

A new research reveals that "fish-lizards" existed in the seas of the Earth 250 million years ago, much earlier than previously believed.

2014 saw the discovery of ichthyosaur fossils on Spitsbergen, a sparsely populated Arctic territory in Norway's Svalbard region. The ancient ichthyosaur was a lizard that resembled fish and had a body form similar to that of dolphins and toothed whales today. The fossils are the oldest ichthyosaur remains ever discovered and the earliest proof of aquatic lizards. The remains, which comprise of 11 tail vertebrae, were imprisoned inside a limestone boulder that dates to the early Triassic era.

It was once believed by scientists that ichthyosaurs and all other aquatic reptiles appeared after the Permian mass extinction event, also known as the "Great Dying," which took place about 251.9 million years ago and caused about 90% of all species on Earth to disappear. As of now, the earliest fossilized marine lizards date to 249 million years ago and come from smaller, less aquatically developed groups. This suggests that marine reptiles first appeared soon after the catastrophic incident.

But in a recent study, researchers contend that the size and makeup of the ichthyosaur bones are proof that the enormous ocean predators may have appeared before the Permian extinction took place. The study was released on March 13 in the journal Current Biology.

It is thought that icthyosaurs and other marine reptiles came from land-dwelling reptiles that gradually adapted to aquatic life to cover an ecological void left after the extinction of oceanic carnivores. The first marine lizard species, which probably had dense bones, less streamlined bodies, and did not reach great sizes, were consequently not ideally adapted to an underwater existence.

The biggest ichthyosaur to ever swim in Earth's seas, according to a tooth found in April 2022, was probably bigger than the current record bearer Shastasaurus sikanniensis, which was 69 feet (21 meters) long.

The bones of the recently discovered ichthyosaur are the same size as those of later ichthyosaurs, which reached lengths of about 9.8 feet (3 meters). Additionally, the bones have a spongy design that seems well suited to underwater living. Because it is improbable that they could have developed these sophisticated characteristics in the less than 2 million years following the calamitous event, the team believes that the ichthyosaur lineage likely originated before the end-Permian mass extinction.

The findings might make palaeontologists reevaluate their assumptions about the Permian global extinction catastrophe.

The experts said in a statement that "it now seems that at least some groups predated this landmark interval." They added that additional old ichthyosaur fossils as well as reptiles from the time of the dinosaurs may be hiding somewhere else in the globe.