Researchers have found the oldest remains of a giant marine reptile known as an ichthyosaur on a remote Arctic island, providing new evidence for how the creatures evolved.
The fossils were found on Svalbard, an island in Norway, along the coast of the deep fjord, a team of Swedish-Norwegian researchers said in an article published in the journal Current Biology on Monday. Previously, the oldest fossils of this type were specimens 248 million years old found in China.
Ichthyosaurs first appeared about 250 million years ago, the researchers say, but became extinct about 90 million years ago. Scientists used to believe that the first ichthyosaurs were primitive creatures that resembled their land-dwelling ancestors. Instead, the researchers found that the fossil belonged to a more advanced aquatic predator, suggesting that previous theories about the reptile’s origins may be wrong.
The study suggests that reptiles likely evolved before the mass extinction known as the Late Permian Mass Extinction, which occurred about 251 million years ago and killed off about 90 percent of species on Earth. Ichthyosaurs became the dominant predators after this event. Fossils were found about 2 million years after the mass extinction.
“The implications of this discovery are many, but most importantly, it shows that the long-awaited transitional ancestor of ichthyosaurs must have appeared much earlier than previously thought,” said lead researcher Benjamin Kear, curator of Vertebrate Paleontology at the Museum of the Evolution. from Uppsala University in Sweden, Reuters reported.
Fossil features suggest the creature was an “advanced aquatic tetrapod” that “must have adapted quickly as a high-sea predator,” the study said.
The fossil found in Norway was about 10 feet long, the researchers said, with a more developed spine. It has been found among other fossils, including fish, sharks, and amphibians.