Forget the monstrous shark depicted in The Meg! Scientists admit we still have no idea what the megalodon really looked like

 For more than a century, scientists have attempted to decipher the appearance of the megalodon, the largest shark that ever lived. 

Now, scientists admit they still have no idea what the legendary creature really looked like when it swam the seas roughly 15 to 3.6 million years ago. In a new study, experts say all previously proposed body forms of the gigantic megalodon remain 'in the realm of speculations'. 

But the academics are hopeful that a full megalodon skeleton – what they describe as the 'ultimate treasure' – will one day be found, which could conclusively reveal what it looked like.  

Reconstruction of a full-scale Megalodon and a set of teeth at the Museo de la Evolución de Puebla in Mexico

Reconstruction of a full-scale Megalodon and a set of teeth at the Museo de la Evolución de Puebla in Mexico

Gigantic: Previous studies suggest the megalodon reached lengths of at least 50 feet (15 meters) and possibly as much as 65 feet (20 meters)

Gigantic: Previous studies suggest the megalodon reached lengths of at least 50 feet (15 meters) and possibly as much as 65 feet (20 meters)

THE LARGEST SHARK THAT EVER LIVED 

O. megalodon was not only the biggest shark in the world, but one of the largest fish ever to exist. 

Estimates suggest it grew to between 49 feet and 59 feet (15 and 18 metres) in length, three times longer than the largest recorded great white shark. 

Without a complete megalodon skeleton, these figures are based on the size of the animal's teeth, which can reach 7 inches long. 

Most reconstructions show megalodon looking like an enormous great white shark, but this is now believed to be incorrect. 

Read more: Megalodon: the truth about the largest shark that ever lived 'The study may appear to be a step backward in science, but the continued mystery makes paleontology, the study of prehistoric life, a fascinating and exciting scientific field,' said study author Kenshu Shimada at DePaul University in Chicago.

'The fact that we still don't know exactly how O. megalodon looked keeps our imagination going. 

'This is exactly why the science of paleontology continues to be an exciting academic field. We'll continue looking for more clues in the fossil record.'  

The megalodon, whose name means 'big tooth', is typically portrayed as a super-sized, monstrous shark in novels and films such as the 2018 sci-fi film 'The Meg'.  

While there is no dispute that they existed or that they were gigantic, the megalodon (officially called Otodus megalodon) is known only from ancient fossilised teeth and vertebrae. 

Based on this evidence, studies suggest they reached lengths of at least 50 feet (15 meters) and possibly as much as 65 feet (20 meters)

Back in 1843, Swiss naturalist Louis Agassiz gave this shark its initial scientific name, Carcharodon megalodon, based on tooth remains.

But more than 150 years on, additional fossil evidence from which to draw conclusions about their bodies, such as a complete skeleton, has not yet been discovered. 

'The cartilage in shark bodies doesn't preserve well, so there are currently no scientific means to support or refute previous studies on O. megalodon body forms,' said lead author Phillip Sternes at University of California, Riverside.  

The legendary creature has been depicted in the 2018 film 'The Meg' (pictured) starring Jason Statham and Rainn Wilson

The legendary creature has been depicted in the 2018 film 'The Meg' (pictured) starring Jason Statham and Rainn Wilson

Paleobiologist Kenshu Shimada (DePaul University, Chicago) holds a tooth of an extinct shark Otodus megalodon, or the so-called 'Meg' or megatooth shark

Paleobiologist Kenshu Shimada (DePaul University, Chicago) holds a tooth of an extinct shark Otodus megalodon, or the so-called 'Meg' or megatooth shark

MEGALODON TAXONOMY 

Megalodon (extinct)

- Species name: Otodus megalodon

- Family name: Otodontidae

- Order name: Lamniformes 

Great white (extant) 

- Species name: Carcharodon carcharias

- Family name: Lamnidae 

- Order name: Lamniformes 

The megalodon is classified into the extinct family Otodontidae, which diverged from the great white shark (Carcharodon carcharias) during the Early Cretaceous period (145 million years to 100.5 million years ago). 

But it's also part of the Lamniformes order, which also includes many modern-day sharks including the great white. 

Traditionally, researchers have modeled megalodon bodies on those of modern great white sharks, partly because they are within the same order and both are partially warm blooded.   

It was previously thought having some warm blood is an advantage that could expand sharks' swimming range, as they can potentially survive in cold climates, unlike clod-blooded fish that are dependent on water temperature. Warm blood is also believed to increase swimming speed.

'Great whites are among the fastest swimming sharks, so megalodons were likely also big, fast sharks you would not want to run into in the open ocean,' said Sternes.

There are eight families of Lamniformes, and 15 species. Previous research, based on two-dimensional geometric shape analyses, took five species of warm-blooded Lamniformes, averaged their fin and body shapes and proposed a general model for megalodons.

While there is no dispute that they existed or that they were gigantic, the megalodon is known only from ancient fossilised teeth and vertebrae. The new research pokes holes into previous ideas about the megalodon's body shape

While there is no dispute that they existed or that they were gigantic, the megalodon is known only from ancient fossilised teeth and vertebrae. The new research pokes holes into previous ideas about the megalodon's body shape

A previous study used two-dimensional geometric shape analyses on the body forms of modern lamnids to propose a body form of the megalodon. The new study examined whether a two-dimensional approach can actually differentiate the body forms represented by modern endothermic (warm-blooded) species from those of modern ectothermic (cold-blooded) ones within the shark order called Lamniformes. Pictured are three living members of Lamnidae - (a) Carcharodon carcharias; (b) Isurus oxyrinchus; (c) Lamna ditropis

A previous study used two-dimensional geometric shape analyses on the body forms of modern lamnids to propose a body form of the megalodon. The new study examined whether a two-dimensional approach can actually differentiate the body forms represented by modern endothermic (warm-blooded) species from those of modern ectothermic (cold-blooded) ones within the shark order called Lamniformes. Pictured are three living members of Lamnidae - (a) Carcharodon carcharias; (b) Isurus oxyrinchus; (c) Lamna ditropis

MEGALODON SHARKS WERE BIGGER THAN EXPERTS THOUGHT 

They ruled the seas for millions of years as one of the most fearsome predators on Earth.

But new estimates suggest gigantic megalodon sharks were actually even bigger than previously thought – measuring up to 65ft (19.8 metres) in length rather than 50ft (15.2 metres). 

Growing to the size of a cricket pitch, it was the most massive shark species to have ever lived and was three times the size of today's largest great whites. 

Read more: Megalodon sharks were BIGGER than we thought at 'up to 65ft' 

Sternes and his colleagues wanted to understand whether the five species used to determine the megalodon's shape differed somehow from the rest of the Lamniformes order, which includes some sharks that are cold blooded too.

The researchers compared the five species to each other, and to the rest of the Lamniformes order. 

Using detailed two-dimensional field guide drawings, they performed quantitative comparisons of the sharks' fin, head and body shapes.

The researchers found no general patterns that would allow them to tease out body shape differences that could potentially inform estimations of what the megalodon looked like. 

This suggests 'there are presently no scientific means to support or refute the accuracy of any of the previously published body forms of O. megalodon'.  

'Although it is still possible that O. megalodon could have resembled the modern great white shark or lamnids, our results suggest that the two-dimensional approach does not necessarily decisively allow the body form reconstruction for O. megalodon,' said co-author Jake Wood at DePaul University.

The study strongly indicates that, two-dimensionally, there is no relationship between thermophysiology and body form in Lamniformes.

So using the great white as a model for the megalodon because they were both warm-blooded cannot reveal much about what the extinct creature looked like.

Fearsome: Megalodons (artist's impression pictured) dominated oceans from about 15 to 3.6 million years ago

Fearsome: Megalodons (artist's impression pictured) dominated oceans from about 15 to 3.6 million years ago

'All previously proposed body forms of Otodus megalodon should be regarded as speculations from the scientific standpoint,' Sternes said. 

'Any meaningful discussion about the body form of O. megalodon would require the discovery of at least one complete, or nearly complete, skeleton of the species in the fossil record.

'I encourage others to explore ideas about its body shape, and to search for the ultimate treasure of a preserved megalodon fossil.' 

The study has been published in Historical Biology.  

HOW BIG WAS THE MEGALODON? 

With a dorsal fin as large as a fully grown human and a total length of up to 65ft, the megalodon dwarfed the biggest shark alive today, the great white, which maxes out at between 15ft and 20ft long.

The oceanic behemoth lived from about 15 million to three million years ago and has featured in Hollywood films, including the Jason Statham blockbuster, The Meg.

In previous studies academics estimated it had a body size of up to 52ft (16 metres).

An individual of this size would likely have had a head around 15ft long, a 5ft 4in dorsal fin and a 12.6ft tall tail.

This means an average-sized adult human could stand on the back of the shark and just manage to peer over the top of the dorsal fin.

However, a new study suggests the calculations used for estimating a megalodon's size were wrong. 

Rather than around 50ft, researchers now say the gigantic extinct shark may have grown up to 65ft in length – the size of a cricket pitch.

Victor Perez, assistant curator of paleontology at the Calvert Marine Museum in Maryland, was lead author

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