By: Sophie Li

Walking down the beach of Blue Anchor with her father, eleven-year-old Ruby Reynolds was looking for something specific: fossils. Ruby has been fossil hunting with her father for most of her life. But in May of 2020, Ruby came across her greatest find to date, an eight-inch-long bone fragment.

This fragment is part of the jawbone of a massive ichthyosaur that lived over 200 million years ago and is the largest marine reptile ever discovered.

Ruby’s father contacted paleontologist Dean Lomax from the University of Bristol and amateur fossil collector Paul de la Salle about the find. In 2018, de la Salle had also uncovered bone fragments from an ichthyosaur, just six miles away from Blue Anchor by the River Severn.

“We kept our fingers crossed for more discoveries,” Lomax said to BBC News. “I was massively impressed—really, really excited. I knew that right at that point we had a second giant jawbone from one of these massive ichthyosaurs just like Paul’s.” The group collected fossils into 2022 and pieced together the ichthyosaur’s lower jawbone. They estimate that the entire fossil would span 82 feet, the size of a blue whale.

To confirm the discovery, the researchers went to Marcello Perillo at the University of Bonn. Perillo identified the crisscrossed collagen fibers, which revealed the bone was one of an ichthyosaur, and that the ancient reptile in question had not fully grown before it died.

The remarkable finding was published in the journal PLOS One, with the specimen named Ichthyotitan severnis, translating to “giant fish lizard of the Severn”.

The fossil provides much insight into the evolutionary history of the ichthyosaur, as the fossil dates to the mass extinction just before the Triassic Period.

“Before, there were hints that there were these giant ichthyosaurs approaching the Triassic-Jurassic boundary, but the amount of evidence is becoming incontrovertible at this point,” said Erin Maxwell, a paleontologist from the State Museum of Natural History, Stuttgart in Germany to The New York Times.
Perillo tells CNN that Reynolds’ discovery can help “understand how evolutionary laws shaped life, what led life to be what it is now.”

The fossils will be displayed at the Bristol Museum and Art Gallery in England.