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.
Claim: Scientists appear to have made incorrect assumptions about the size and shark-like shape of the prehistoric fish Dunkleosteus Terrelli. Many experts thought it was up to 30 feet tall, but new research suggests it was more likely to have been 11 to 13 feet
Scientists also thought its body resembled a shark, but a new study suggests it had a torso more like a tuna. It found that the “sea monster” was probably shorter and stockier than previously believed
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.’
WHAT DO SCIENTISTS GET ‘WRONG’ ABOUT DUNKLEOSTEUS?
Original Faith: 30ft (9 meters long)
New claim: 11-13ft (4-5 meters long)
Original belief: shark-like body shape
New claim: Tuna-like body shape
Original belief: the size should be calculated based on the whole head
New claim: Size should be calculated based on its head, minus the muzzle
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.”
As an arthrodira, Dunkleosteus had a bony, armored head (pictured) but an internal cartilage skeleton, meaning that only the heads of these creatures were preserved 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 the 24-inch-long head, minus the muzzle
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.
This is considered a way to more accurately measure arthrodires based on what is known of the complete skeletons of smaller relatives of Dunkleosteus
This image shows how short fish have short heads and long fish have long heads
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.
THE EARTH HAS HAD FIVE MAJOR EXTINCTION EVENTS WITH THE MOST FAMOUS A DINOSAUR KILLING ASTEROID
Five times the vast majority of life in the world has been extinguished in what are called mass extinctions.
Late Ordovician mass extinction
The first of the traditional big five extinction events, about 540 million years ago, was probably the second most serious. Virtually all life was in the sea at the time and about 85% of these species disappeared.
Mass extinction in the late Devonian
About 375-359 million years ago, major environmental changes caused a long-lasting extinction event that wiped out large fish groups and halted the formation of new coral reefs for 100 million years.
Five times, the vast majority of life in the world has been extinguished in what are called mass extinctions. The best known is perhaps the End Cretaceous, which wiped out the dinosaurs. Artist’s impression
End-Permian mass extinction (the Great Die)
The largest extinction event and the one that most profoundly affected Earth’s ecology occurred 252 million years ago. As many as 97% of the species that leave a fossil record are gone forever.
End-Triassic mass extinction
Dinosaurs first appeared in the early Triassic, but large amphibians and mammal-like reptiles were the dominant land animals. The rapid mass extinction that occurred 201 million years ago changed that.
Mass extinction in the end of the Cretaceous
An asteroid slammed into Earth 66 million years ago and is often blamed for ending the reign of the dinosaurs.