A new study has revealed that a fossilized ichthyosaur unearthed on a beach in southwest England dating back 200 million years may be part of one of the largest marine reptiles ever discovered. The findings were published in the journal Public Library of Science ONE on April 17th.
An illustration of the carcass of an ichthyosaur washed up on a beach. Image source: Sergey Krasovskiy
In 2020, amateur fossil hunters stumbled upon a massive bone on the Blue Anchor beach in Somerset, England. Further examination revealed it to be a fragment of the lower jawbone of a giant ichthyosaur. Ichthyosaurs were marine reptiles that lived in the oceans from 250 million to 90 million years ago.
Subsequent excavations unearthed 11 more fragments, allowing the research team, led by Dean Lomax from the University of Manchester, to partially reconstruct a bone located at the back of the jawbone, known as the surangular.
In 2018, a report described a similar ichthyosaur jawbone found on another beach in Somerset. At the time, the research team lacked enough evidence to determine its species.
"It's obvious that the new find is another massive lower jawbone," said Lomax. "So I'm very excited."
After comparing the partial surangular with complete surangular bones from other ichthyosaurs, the research team estimated that the entire bone was at least 2 meters long, suggesting that the animal's length was approximately 20 to 25 meters.
"We're dealing with a truly gigantic creature," Lomax said. "It's definitely the largest marine reptile formally described."
Lomax noted that the nature of this surangular fossil aligns with the fossil reported in 2018, indicating that these two fossils definitely belong to a previously undescribed species of ichthyosaur.
These remains date back to approximately 202 million years ago, after which a large-scale global extinction event occurred, leading to the extinction of many species—including numerous giant ichthyosaurs.
"They truly were the 'last of the giants,'" Lomax said. "No ichthyosaur could ever reach this size again."
Related paper information: https://doi.org/10.1371/journal.pone.0300289
