Researchers say monstrous shark ruled ancient seas before megalodon

In the age of dinosaurs — before whales, great whites or the bus-sized megalodon — a monstrous shark prowled the waters off what’s now northern Australia, among the sea monsters of the Cretaceous period.Researchers studying huge vertebrae discovered on a beach near the city of Darwin say the creature is now the earliest known mega-predator of the modern shark lineage, living 15 million years earlier than enormous sharks found before.And it was huge.The ancestor of today’s 20-foot great white shark was thought to be about 26 feet long, the authors of a paper published in the journal Communications Biology said.“Cardabiodontids were ancient, mega-predatory sharks that are very, very common from the later part of the Cretaceous, after 100 million years ago,” said Benjamin Kear, the senior curator in paleobiology at the Swedish Museum of Natural History and one of the study’s authors.

“But this has pushed the time envelope back of when we’re going to find absolutely enormous cardabiodontids.”Sharks have a 400-million-year history but lamniforms, the ancestors of today’s great white sharks, appear in the fossil record from 135 million years ago.At that time they were small — probably only a meter in length — which made the discovery that lamniforms had already become gigantic by 115 million years ago an unexpected one for researchers.The vertebrae were found on coastline near Darwin in Australia’s far north, once mud from the floor of an ancient ocean that stretched from Gondwana — now Australia — to Laurasia, which is now Europe.It’s a region rich in fossil evidence of prehistoric marine life, with long-necked plesiosaurs and ichthyosaurs among the creatures discovered so far.The five vertebrae that launched the quest to estimate the size of their mega-shark owners were not a recent discovery, but an older one that had been somewhat overlooked, Kear said.Unearthed in the late 1980s and 1990s, the fossils measured 4.7 inches across a...