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A shark with teeth as big as your hand have be huge. But when teeth are all you have to go on, you’ll have to think outside the box to find out what the rest of the extinct monster looked like.
Turns out, the pelagic horror we refer to as Megalodon might have seemed a bit more cartoonish than Hollywood would have us believe. It was certainly huge, but relative to its impressive length, it might as well have had a cute snoot and large flippers and flippers to boot.
To get a better idea of the extinct giant’s precise proportions, paleontologists at the University of Bristol and the University of Swansea in the UK turned to the growth patterns of its closest living relatives.
New reconstruction of the body proportions of Megalodon. (Oliver E. Demuth)
You would think this meant collecting data on great white sharks (Carcharodon carcharias). After all, these modern day apex predators are a convenient point of comparison for a giant shark that navigated our oceans for some 20 million years, before disappearing a few million years ago.
The taxonomy is complicated enough when you have to work with whole bodies. But the cartilage that makes up sharks’ skeletons doesn’t stick around for long after they die, meaning paleontologists are mostly left with only teeth on which to base their estimates.
And the exact position of the Megalodon branch in the shark family tree is a bit confusing. Originally, in the late 19th century, Megalodon was also included in the genus Carcharodon, directly linked to the great white sharks of the Lamnidae family.
This has led to representations of the shark as a white shark, only a few times longer, reaching 15 to 18 meters from nose to tail.
Not everyone was convinced that this is a fair comparison. Some think that the shape of the animal’s teeth implies that it was the end of the line of the extinct family Otodontidae, in which case it is part of the genus. Carcharocles, or perhaps Otodus.
This is the lineage on which the team of paleontologists has based their latest assessment, an assumption that implies that Megalodon had a slightly more complicated pedigree.
“The megalodon is not a direct ancestor of the great white, but it is equally related to other macro-predatory sharks such as the makos, salmon shark and porbeagle shark, as well as to the great white shark,” says Catalina Pimiento of Swansea University. .
“We collected detailed measurements of the five to make predictions about the Megalodon.”
Those predictions were based on a combination of mathematical analyzes chosen to resolve the question of how anatomical features such as fins, head and tail scaled as the shark expanded in length.
Central to their calculations was the question of how the proportions of related sharks may have adjusted as they aged.
Human babies, for example, aren’t exactly miniature adults. A 1.6 meter tall newborn will not pass for a bank manager, no matter how elegant his suit may look.
Sharks, on the other hand, could get away with it.
“[W]We were surprised and relieved to find that, in fact, the babies of all these modern predatory sharks start out as small adults and do not change in proportion as they grow, “says paleontologist Mike Benton of the University of Bristol.
This means that they could take the growth curves of sharks thought to be related to Megalodon and apply them to their extinct cousin, confident that their own fins, head and tail will similarly expand to their final estimated size.
Now we can imagine an adult 16 meters long Otodus megalodon with a head that was almost a third the size of its entire body, around 4.65 meters, a tail fin of around 3.85 meters and a dorsal fin of 1.62 meters.
If you want some perspective, this would be like parking three cars and standing in the middle one. The first car would be roughly the length of its head and your height would be the height of its dorsal fin.
For lead author Jack Cooper, a researcher who had just finished his graduate studies in paleontology at the University of Bristol, it was an exciting picture to describe.
“Megalodon was actually the same animal that inspired me to pursue paleontology in the first place when I was only six years old, so I was on the moon for a chance to study it,” says Cooper.
“This was my dream project. But studying the entire animal is difficult considering that all we really have are many isolated teeth.”
Whether this new way of imagining a classic prehistoric beast is scarier or a little more adorable, we’ll leave it up to you.
This research was published in Scientific reports.
