LEILA FADEL, HOST:
Millions of years ago, giant marine reptiles called ichthyosaurs were the dominant predators of the world's oceans. Researchers have now unearthed what may have been the largest of these creatures, an ichthyosaur roughly 82 feet in length. That's more than two school buses long. Here's science reporter Ari Daniel.
ARI DANIEL, BYLINE: This all started not quite eight years ago. A fossil collector was combing a beach in Somerset in southwest England when he came upon chunks of fossilized bone. He showed them to his longtime friend, paleontologist Dean Lomax, based at the universities of Bristol and Manchester.
DEAN LOMAX: They fit together perfectly, like an ancient prehistoric jigsaw puzzle, and we could work out it belongs to a jawbone of a reptile that swam in the seas at the time of the dinosaurs.
DANIEL: A marine reptile called an ichthyosaur - think chunky shark with a long, toothy snout, fins and four flippers.
LOMAX: They didn't come on to land. These are reptiles very, very distantly related to things like crocodiles.
DANIEL: The specimen was 202 million years old from the end of the Triassic Period. But the thing that struck Lomax was how big the jawbone fragment was - over three feet long.
LOMAX: It suggests that it was from something unusual and something exceedingly large.
DANIEL: Lomax published a description of the bone, but it was partly eroded.
LOMAX: What we'd hoped for - we kept our fingers crossed - maybe more specimens would come to light in the future.
DANIEL: Then one day in 2020, 11-year-old Ruby Reynolds and her father found two pieces of a fossilized bone on a beach in Somerset.
RUBY REYNOLDS: I just went further up the beach to the muddy slope and it was just sort of lying there. I was just happy, really.
DANIEL: She and her dad did some internet sleuthing, discovered Lomax and sent him an email.
REYNOLDS: Saying, you know, hey, Dr. Lomax, we think we found another one of your giant ichthyosaur jawbones.
DANIEL: They later located additional fragments, allowing Lomax and his colleagues to piece together a second jawbone from the same kind of giant ichthyosaur. They were now confident this was a new species, one they coined Ichthyotitan severnensis that was likely massive.
LOMAX: Genuinely enormous, about the length of a blue whale, and that puts it at probably the largest marine reptile.
DANIEL: With this second specimen in hand, he invited the amateur fossil finders to co-author a publication with him, including Reynolds, who's now 15.
RUBY: It's just crazy. Never something I would have expected to happen.
DANIEL: The results appear in the journal PLOS ONE. Kelsey Stilson is a biomechanist at the National Museum of Natural History in Paris, who wasn't involved in the research.
KELSEY STILSON: There were things that we can't even possibly imagine in the past. We can get little hints, and this is one little hint at kind of this larger picture.
DANIEL: A picture of how life evolved on Earth. The Triassic was, in Stilson's words, a really weird time.
STILSON: That's when you see the first very early mammals and the first very early dinosaurs - everything starting right then.
DANIEL: At the end of the Triassic - that's when these colossal ichthyosaurs reigned, right before a mass extinction event that swallowed up these animals forever. Dean Lomax again.
LOMAX: No marine reptile ever reached such gigantic sizes ever again.
DANIEL: Not all ichthyosaurs vanished, but even the smaller ones eventually went extinct, which created an opening in the ocean.
LOMAX: A niche to be filled, which is where eventually you had mammals, including the first whales, eventually made that transition into the ocean.
DANIEL: Where they took over as the dominant marine predators. Underwater reptilian rule was over.
For NPR News, I'm Ari Daniel. Transcript provided by NPR, Copyright NPR.
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