Ellen Phiddian
Cosmos science journalist
The megalodon – the giant shark that lived between 15 and 3.6 million years ago – has captured the imagination of thousands of people, and at least one filmmaker, over time.
But, while we know Otodus megalodon was huge, there’s not enough fossil evidence to confirm its shape.
And, according to new research in the journal Historical Biology, palaeontologists’ current guesses about the shape of megalodons are based on potentially incorrect assumptions.
“The cartilage in shark bodies doesn’t preserve well, so there are currently no scientific means to support or refute previous studies on Otodus megalodon body forms,” says Phillip Sternes, an organismal biologist at the University of California, Riverside, and lead author on the study.
Palaeontologists have previously modelled the megalodon’s shape on its modern relative, the great white shark. Megalodons are thought to be partially warm blooded, like great whites, and both belong to the order Lamniformes.
Previous researchers have used measurements from the other five warm-blooded lamniforms to figure out the fin size and shape of the megalodon. But there are cold-blooded lamniforms as well, and in this paper, the researchers ask if they should also have been examined.
The researchers compared the physical characteristics of the warm-blooded lamniforms to other sharks in the order. They found no characteristics that distinguished the warm-blooded sharks from the cold.
“Warm bloodedness does not make you a differently shaped shark,” summarises Sternes.
“I encourage others to explore ideas about its body shape, and to search for the ultimate treasure of a preserved megalodon fossil. Meanwhile, this result clears up some confusion about previous findings and opens the door to other ideas once again.”
The researchers conclude that they still don’t have a clear understanding of the shape of the megalodon. While only teeth and vertebrae can be found, it will be difficult to confirm what the megalodon looked like.
“All previously proposed body forms of Otodus megalodon should be regarded as speculations from the scientific standpoint,” says Sternes.
Co-author Professor Kenshu Shimada, a palaeobiologist at DePaul University, US, says that while the study may appear to be a step backward in science, “the continued mystery makes palaeontology – the study of prehistoric life – a fascinating and exciting scientific field.
“The fact that we still don’t know exactly how Otodus megalodon looked keeps our imagination going.
“This is exactly why the science of palaeontology continues to be an exciting academic field. We’ll continue looking for more clues in the fossil record.”