A new discovery by paleontologists points to a change in the evolutionary timeline of sharks, after vertebrae found in Australia point to a shark that lived around 115 million years ago, with an estimated size of up to eight meters, according to a new article in the journal Communications Biology.
Sharks are a reference predator in today’s oceans and their origin dates back to more than 400 million years ago. However, the evolutionary history of modern shark lineages began during the Age of Dinosaurs, with the oldest known fossils dating to around 135 million years ago.
Known as lamniforms, these first modern sharks were small, possibly around 1 meter long, but over time they gave rise to giants, such as today’s great white shark, which is a predator in today’s oceans and reaches around 6 meters.
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But the discovery in Darwin, Australia, revealed the presence of an unexpected predator: a gigantic lamniform shark. The five vertebrae recovered were partially mineralized, which allowed them to be preserved, and are virtually identical to those of a modern great white shark.
However, while the vertebrae of adult white sharks are about 8 cm in diameter, the vertebrae of Darwin’s fossil lamniform were more than 12 cm wide.
They were also morphologically distinct enough to be identified as belonging to a cardabiodontid, that is, huge mega-predatory sharks that roamed the world’s oceans about 100 million years ago.
Significantly, however, Darwin’s lamniform is about 15 million years older and had already reached the massive body size characteristic of cardabiodontids.
