Bigger than a blue whale: 11-year-old's discovery of 6.5-foot jawbone reveals Earth's largest marine reptile

An 11-year-old girl on a casual family fossil hunt on a beach in Blue Anchor, Somerset, England, has helped uncover what scientists believe is the largest marine reptile ever to have lived, a creature so vast it rivals the blue whale in size and dates back some 202 million years to the Late Triassic period, reports Art Threat.

Ruby Reynolds and her father Justin were walking the mudflats at Blue Anchor when they spotted fragments of an enormous jawbone measuring more than six and a half feet long. The find, when combined with a specimen discovered in 2016, gave scientists their first comprehensive look at a previously unknown species, now formally named Ichthyotitan severnensis, estimated to have stretched roughly 82 feet from head to tail.

The father and daughter photographed their discovery and contacted palaeontologist Dean Lomax at the University of Bristol, who led a research team to Somerset to carefully extract the fossil. Their findings were subsequently published in the journal PLOS ONE.


Lomax and his team scaled up the bones using comparisons with related ichthyosaur species such as Shonisaurus, arriving at size estimates that place Ichthyotitan severnensis in the same size class as a modern blue whale, which averages around 100 feet in length. Microscopic examination of the bone structure revealed the animal was still growing when it died, suggesting some individuals may have reached even greater dimensions.

"These jawbones provide tantalising evidence that perhaps one day a complete skull or skeleton of one of these giants might be found," Lomax said. "You never know."

Scientists believe Ichthyotitan severnensis was the apex predator of its era, hunting fish, squid-like cephalopods and smaller marine reptiles across warm Triassic seas in what is now Britain. Evidence on the fossil jaw showed it had been nibbled by scavengers after the creature died. Unlike the bulky dinosaurs that dominated land at the time, ichthyosaurs gave birth to live young and were built for speed and endurance across open ocean.

What makes the discovery particularly significant is what it reveals about the timing of oceanic giants. Ichthyotitan severnensis did not represent a species in decline but one at the peak of its dominance, thriving just before a catastrophic mass extinction 201 million years ago wiped out these marine giants entirely. Later ichthyosaurs never again reached such proportions. The oceans would remain without giant marine reptile apex predators until whales evolved some 50 million years ago.

Somerset's eroding coastal cliffs continue to expose fossils with each passing winter, and further expeditions are planned along the English coastline in search of additional Ichthyotitan severnensis remains. A complete skull or skeleton, researchers say, could finally answer outstanding questions about the animal's exact dimensions, hunting behaviour and evolutionary relationships. The research team credited Ruby Reynolds and other amateur beachcombers for their role in advancing palaeontological discovery, suggesting that many more finds may yet be waiting in the mudflats of Somerset.