It may be hard to imagine, but the county of Somerset in southwestern England was once home to what may have been the largest marine reptiles to have ever lived, my team’s new study reveals.
Eight years ago, a strange and enormous jawbone was discovered on the English coast, but my team hesitated to identify it as a new species until more specimens came to light. Now, with the discovery of a second giant jawbone several years later, we have named a new species of ichthyosaur, an ancient marine reptile.
Prolific fossil hunter in 2016 Paul de la Salle, has unearthed a giant jawbone from Lilstock beach in Somerset. It was an incomplete bone from the back of the animal’s lower jaw. My team, including De la Salle, studied this discovery and published our findings in 2018 in the journal PLOS One.
Read more: How we found a giant ichthyosaur almost the size of a blue whale
His find was important because it was recovered from about 202 million year old rocks, was very large (1 meter long but incomplete) and clearly belonged to a new species of giant ichthyosaur. The jawbone (called surangular) had an unusual shape and structure. But we have refrained from naming the discovery in the hope that more fossil remains would follow in the future.
Enter a second, more complete and better preserved specimen, this time a right rectangular specimen from a different individual.
This latest discovery was made in 2020 just ten kilometers along the coast near Blue Anchor. He was found by father and daughter Justin and Ruby Reynolds, who were fossil hunting (Ruby was 11 at the time). They contacted me almost immediately when they found it. Over the next few years, De la Salle and some of our family members collected more fossil fragments, with the last piece found in October 2022.
When we started joining different parts of the same jawbone together, we estimated that the entire bone would have been just over 2 meters long. The conservation and fine details provided new information that also helped us to better reinterpret De la Salle’s original bone.
Now we had two specimens with the same unique features, collected from the same geological time zone. And the fact that these two bones appeared about 13 million years after the last dated giant ichthyosaurs with a scientific name, including Shonisaurus sikanniensis from British Columbia, Canada, and Himalayasaurus tibetensis from Tibet, China, supported our identification of a new species.
We have therefore established a new genus (taxonomic rank) and species of giant ichthyosaur which we have named Ichthyotitan severnensismeaning ‘giant fish lizard of the Severn’.
Giants the size of a blue whale
With only two gigantic jawbones, it’s impossible to say for sure how big Ichthyotitan really and truly. However, we know that both specimens are about 25% larger than the same bone in the giant Shonisaurus sikanniensisan earlier ichthyosaur collected from British Columbia with an estimated body length of 21 meters.
Using a basic formula called a simple scale factor, we can estimate that our ichthyosaur was up to 26 meters long, about the size of a blue whale. Comparisons with the same bone in other ichthyosaurs suggest so Ichthyotitan was between 20 and 26 meters long.
We must be cautious with such estimates because of differences between species, such as those with long or short snouts. However, simple scaling is a common way to estimate size in paleontology, especially when dealing with fossil fragments. So based on the information we have available now, Ichthyotitan severnensis is probably the largest marine reptile formally identified by scientists.
The fossils are 202 million years old and barely predate a global extinction event that wiped out these giants – and marine reptiles would never reach such sizes again. We think they belonged to a family of ichthyosaurs called Shastasauridae, which disappeared during the mass extinction at the end of the Triassic. The cause is a source of debate among scientists, but may have been caused by a sudden release of large amounts of carbon dioxide.
As part of our research, we also looked at bone histology (its microscopic anatomy). Marcello Perillo from the University of Bonn led this side of the work. Thin sections of the bones revealed the same microscopic features as similar giant ichthyosaur specimens. The research also showed that this giant was not yet fully mature and was still growing at the time of death.
Everyone can contribute
When I received the first email from the Reynolds outlining their findings, I had a smile on my face knowing that we now had a second copy. I was also impressed that they correctly identified the discovery as a huge jawbone of an ichthyosaur and recognized that it matched De la Salle’s earlier find. I asked them if they would like to join my team to study this fossil and they agreed.
Ruby Reynolds is now a published scientist who not only found a giant prehistoric reptile, but also helped name it. There probably aren’t many 15 year olds who can say that. She, her father, and De la Salle all contributed to our understanding of the ancient world.
Paleontology is one of those sciences to which everyone can make an important contribution. You don’t have to be a professor or world expert. You just need a sharp eye, a lot of patience and a little bit of luck.
It’s remarkable to think that giant reptiles the size of a blue whale swam in the oceans around what was Britain hundreds of millions of years ago. These jawbones provide tantalizing evidence that a complete skull or skeleton of one of these giants may one day be found.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Dean Lomax worked with Paul de la Salle, Marcello Perillo, Justin and Ruby Reynolds, and Jimmy Waldron of the Dinosaurs Will Always Be Awesome Museum on the said research. He dedicates the work to Paul de la Salle, who discovered the first surangular in 2016.