Earth’s deadly megalodon is a popular villain in Hollywood sci-fi, but new research says that, actually, we really have no idea what these animals looked like. Otodus megalodon, commonly depicted as a heckin’ massive shark could well have mirrored the body plan of extant great whites, but the reality is that – scientifically speaking – all of these estimations are speculation.
Previous research has taken a punt at estimating the true size of mighty megalodon by pooling data on its descendants including mako, salmon shark and porbeagle shark, and the great white. They were then able to compare these details against the remains of megalodons we have to this day: their giant gnashers.
Using tooth size as an indicator of body plan, they estimated megalodon was 16 meters (52 feet) long with fins the size of an adult human, but is this accurate? This new paper, led by Phillip Sternes at the University of California at Riverside, and published in the journal Historical Biology, decided to investigate.
Megalodon was not a lamnid shark like the great white, but it’s thought to have been partially warm-blooded as a fellow active predator. As such, science has turned to the lamniformes as a rough blueprint for megalodon.
In the new paper, researchers explored two-dimensional geometric shape analyses to establish if they could differentiate the body forms of extant warm-blooded species from those of extant cold-blooded species within the lamniformes. The intention was to suss out if thermophysiology was reliably indicative of body form within these sharks, and their results revealed it isn’t.
What this means is that estimating megalodon’s body type through the pivotal viewpoint that its partial warm-bloodedness informs its shape isn’t accurate enough to be considered scientifically substantiated.
“I would not be surprised if Megalodon indeed resembled such modern species that have been used as analog, but the new study suggests that it cannot be scientifically substantiated based on the present fossil record,” said Kenshu Shimada, a paleobiology professor at DePaul University in Chicago, to IFLScience.
“We really need additional fossil materials other than teeth and vertebrae. Even if one can discover a small portion of the skeleton, such as a skull or fin, it would offer more clues about the shark's original body form.”
If, as has been previously estimated, megalodons were so effing huge, why is it that we’ve not found more of them? Like all sharks, megalodon’s skeleton was made up of poorly mineralized cartilage which doesn’t fare well in the fossilization process. Finding a megalodon skeleton is, then, unlikely, but not impossible.
“Its vertebrae were weakly calcified, so they are occasionally preserved, but much of the fossil record of Megalodon is known from its hard well-mineralized teeth,” continued Shimada.
“If any skeletons are preserved in rocks somewhere, they must have become buried very rapidly before decay or scavenging by other organisms. Such skeleton-bearing rocks then must have survived through various geologic processes, including eventual weathering which is a typical way in which fossils become exposed and are discovered.”
In the meantime, we continue to speculate from the dribs and drabs of megalodon at our disposal, but what information they really provide on megalodon's body form remains unclear.
Marine animals certainly aren’t afraid to get creative when it comes to body plan. We need only look to the gulper eel for evidence that large jaws don’t always equal a girthy fish. While we await the discovery of some more comprehensive megalodon remains, perhaps Hollywood can pass the time letting their imaginations run wild for The Meg 2: This Time, It’s Noodly.
