Prehistoric fish with a mouth twice as large as a great white ruled waters 360 million years ago

It lived during the Fish Age and was the first vertebrate “superpredator” on Earth.

But it seems scientists have made incorrect assumptions about the size and shark-like shape of the “strange” beast now nicknamed “Chunky Dunk.”

The species Dunkleosteus terrelli, which was “built like a wrecking ball” and had a mouth twice the size of a great white shark, lived in shallow subtropical waters above what is now the US city of Cleveland about 360 million years ago.

It was an armored prehistoric fish that many experts initially thought was up to 30 feet long.

However, a new study claims that the length of this prehistoric predator may have been greatly exaggerated since its fossilized remains were discovered on the shores of Lake Erie in 1867.

Instead, researchers suggest that the “sea monster” Dunkleosteus was in fact much shorter and stockier — perhaps more like 11 to 13 feet (3 to 4 meters) long.

“Dunkleosteus is already a strange fish, but it turns out that the old estimates led us to miss many features that made this fish even more strange, such as a very tuna-like torso,” said lead author Russell Engelman of Case Western Reserve. University in Cleveland.

‘Some colleagues have called it ‘Chunky Dunk’ or ‘Chunkleosteus’ after seeing my research.’

Most of the previous analysis of the prehistoric fish was conducted using specimens in the Cleveland Museum of Natural History, which has the largest and highest quality collection of Dunkleosteus remains in the world.

But little research has been done on the fish since the 1930s, Engelman said.

“Without reliable size estimates, not much could be said about Dunkleosteus scientifically except ‘Look at the big, scary fish!'” Engelman added.

“These length estimates were an example of something that just eluded everyone’s attention because this fish was believed to be well studied.”

Most species length estimates weren’t based on hard evidence, Engelman said, because Dunkleosteus was a type of extinct fish called an arthrodire.

Unlike modern fish, these arthrodires had bony, armored heads but internal skeletons made of cartilage, meaning that only the heads of these animals have survived as fossils.

Because of this, its size and shape is often a mystery.

The new study claims that Chunky Dunk’s height should actually be calculated by basing it on his 24-inch-long head, minus the muzzle.

This is considered a more accurate measure of arthrodires based on what is known of the complete skeletons of lesser relatives of Dunkleosteus.

“The reasoning behind this study can be summed up in one simple observation,” Engelman said. “Short fish generally have short heads and long fish generally have long heads.”

Based on that method, Engelman concluded that Dunkleosteus was only 11 to 13 feet tall — much shorter than previous research had suggested.

“Dunkleosteus has often been reconstructed under the assumption that it was shaped like a shark,” Engelman said.

However, the shorter body and shape of the body armor also meant that the prehistoric fish that lived in the Devonian period were likely much larger.

“An 11-foot Dunkleosteus is essentially the same weight as a 15-foot great white shark,” Engelman said.

“These things are built like wrecking balls. The new proportions for Dunkleosteus may look silly until you realize he has the same body shape as a tuna… and a mouth twice the size of a great white shark.”

The new size estimates also have a broader scientific context.

It means that Dunkleosteus is part of a wider evolutionary story, in which vertebrates grew from small, humble bottom-dwellers to huge giants.

“While the scaled-down size may seem disappointing to Dunkleosteus,” said Engelman, “it was probably still the largest animal to exist on Earth at that time.”

And these new estimates make it possible to do so many types of analysis on Dunkleosteus that it was never thought possible. This is the bitter pill to swallow so that we can now get on to the fun stuff.’

Patricia Princehouse, associate director of Case Western Reserve University’s Institute for the Science of Origins said: “This fresh take on the legendary Dunkleosteus “sea monster” shows that there are many brand new breakthroughs waiting to be discovered in the world of paleontology, even with known species.’

The new study is published in the journal diversity.