Fossils discovered by an 11-year-old girl on a beach Somerset may have come from the largest marine reptile that ever lived, according to experts.
The fossils are thought to be from a type of ichthyosaur, a prehistoric marine reptile that lived at the time of dinosaurs. The newly discovered species is thought to have wandered into the sea around 202m years ago towards the end of the Triassic.
The team named the species Ichthyotitan severnensis, meaning “giant fish-lizard of the Severn”.
“This giant probably represents the largest marine reptile that has been formally described,” said Dr Dean Lomax, a palaeontologist at the University of Bristol and co-author of the research, adding that comparisons with fossils of other ichthyosaurs suggested that the creature would be about 25 meters long. in length – about the size of a blue whale.
“Of course we have to be careful with such estimates, because we are dealing with fragments of giant bones,” he added. “However, simple scaling is commonly used to estimate size, especially when comparative material is scarce.”
The team says samples from the fossils indicate that the animal was still growing. And there’s another twist.
“We believe these ichthyosaurs are the last surviving members of the family called shastasaurida, which died out during the global mass extinction event at the end of the Triassic,” said Lomax.
Write in the journal Plos OneLomax and colleagues report how the first pieces of the jaw were discovered by Justin Reynolds and his daughter Ruby – co-authors of the paper – on the beach at Blue Anchor in May 2020, when Ruby was 11.
The pair contacted Lomax, who joined the search for further pieces along with members of the Reynolds family. Among those also joining the hunt was Paul de la Salle, an expert at the Museum of Jurassic Marine Life in Dorset who in 2016 discovered a jawbone of what appeared to be a new species of ichthyosaur at a beach in Somerset. That monster was subsequently studied by Lomax and colleagues.
When the team matched the fragments of the new fossil, they found that it belonged to the same species as the specimen discovered by De la Salle.
In both cases, the fossilized bone is the orangular—a long, curved structure that sits at the top and back of the lower jaw.
Lomax said: “When my team described the first specimen in 2018, it showed unusual features that suggested it might represent something new. However, we refrained from naming it as it was incomplete and also partially eroded.”
“Having two examples of the same bone with the same unique features from the same geological time zone supports our identification of something new, especially when combined with the fact that these two bones appear approximately 13m years after their latest named geological relatives ,” he added.
Dr Nick Fraser, a palaeontologist at National Museums Scotland, who was not involved in the study, said the identification of the bone as part of the lower jaw of an ichthyosaur was very convincing.
“This suggests that its one-time owner was a gigantic animal, possibly one of the largest marine reptiles of all time,” he said.
But Fraser said it was questionable whether the animal should be designated a new species. “To me, it’s a little too incomplete for that,” he said.
