In 1811, a 12-year-old girl named Mary Anning discovered a fossil on the beach near her home in southwest England: the first scientifically identified specimen of an ichthyosaur, a dolphin-like oceanic reptile from the time of the dinosaurs. . Two centuries later, less than 50 miles away, an 11-year-old girl named Ruby Reynolds found a fossil of another ichthyosaur. It appears to be the largest marine reptile known to science.
Ms. Reynolds, now 15, and her father, Justin Reynolds, have been fossil hunting for 12 years near their home in Braunton, England. During a family trip in May 2020 to the village of Blue Anchor along the Severn River estuary, they came across a piece of fossilized bone embedded in a rock.
“We were both excited because we had never found such a large piece of fossilized bone before,” Reynolds said. Her daughter continued searching on the beach, she added, “and it wasn't long before she found another, much larger piece of bone.”
They brought home the bone fragments, the largest of which was about eight inches long, and began their search. A 2018 paper provided a clue to what they had found: In nearby Lilstock, fossil hunters had discovered similar bone fragments, hypothesized to be part of the jaw of a huge ichthyosaur that lived about 202 million years ago. However, scientists who had worked on the Lilstock fossil had deemed that specimen too incomplete to designate a new species.
Mr Reynolds contacted these researchers: Dean Lomax, of the University of Bristol, and Paul de la Salle, an amateur fossil collector. They joined the Reynolds family on collecting trips to Blue Anchor, digging in the mud with shovels. Ultimately, they found about half of a bone that they estimated would be more than seven feet long when completed.
Several characteristics of the bone's shape indicate that it came from the jaw of an ichthyosaur. To further confirm its identity, the researchers collaborated with Marcello Perillo, a paleontologist at the University of Bonn in Germany. Under the microscope, he found crisscrossing collagen fibers, a characteristic of the ichthyosaur. He also saw that, despite the gigantic size of its jaw, the reptile had not finished growing when it died.
Taken together, the Blue Anchor and Lilstock fossils offered evidence of something special.
“Having two examples of the same bone that retained all the same unique features, from the same geological time zone, supported the identification that we played with before, that it must be something new,” Dr. Lomax said. “That's when it got really emotional.”
He and his co-authors of a paper describing the fossil published Wednesday in the journal PLOS One named it Ichthyotitan severnensis, the giant Severn fish lizard.
Their estimates suggest that Ichthyotitan could have been up to 82 feet long, rivaling the size of a blue whale and making it the largest marine reptile known to science. It lived just before the massive extinction that ended the Triassic period.
“Inevitably, with big extinction events, obviously, it's the biggest things that go first, and so in this case, literally the biggest things in the ocean, they get wiped out and the whole family disappears,” he said Dr. Lomax.
Erin Maxwell, a paleontologist at the State Museum of Natural History in Stuttgart in Germany who was not involved in the study, said the discovery sheds light on the evolution of ichthyosaurs. “Previously, 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,” she said.
Dr Lomax said this discovery also highlighted the importance of amateur fossil collectors. “If you have a keen eye, if you have a passion for something like this, you can make discoveries like this,” he said.
Ruby Reynolds said: “When I first found the piece of ichthyosaur bone, I didn't realize how important it was and what it would lead to. I think the role young people can play in science is to enjoy the journey of exploration because you never know where a discovery might take you.”