New research reveals the true size of the ancient monster “dunk”. Biodiversity

The bony fish dunkleosteus terrelliNicknamed “Dunk”, it was one of the many predators that prowled the oceans during the Devonian period (419 million to 358 million years ago). This massive, armored fish had blade-like jaws that could snap open with a force of 8,000 pounds. The first fossils Terelli Discovered 150 years ago along the shores of Lake Erie near the city of Cleveland, the largest known specimen is in the collections of the Cleveland Museum of Natural History in the United States.

Unlike modern fish, which have cartilage or bony skeletons, Terelli It had an armored bony skull attached to a cartilaginous skeleton. The skull was about 85 cm high and resembled the main character from the movie “Alien”.

It turns out that only the skulls of these creatures are fossilized. Thus, early researchers extrapolated to volume Terelli From the relationship between the size of a shark’s skull and its body length. Over the next 150 years, the species would become a local icon of paleontology, even becoming Prehistoric fish Ohio state official. Despite this, very little scientific work has focused on the species.

During the pandemic, Russell Engelman, a doctoral student at Case Western University in Cleveland, found himself unable to conduct his normal lab research. Instead, he went to the Cleveland Museum of Natural History to ponder some research questions. when examining samples TerelliEngelman ran into a problem. He said, “Everything in biology is affected by body size.” Science lives. “I tried using some old analogy, and it just didn’t make sense biologically.”

Try as he might, Engelman couldn’t reconcile the skull with a 30-foot body. All of his reconstructions required strange, unrealistic body proportions that bear no resemblance to the original drawings. Decided of course Find out how the original researchers determined the size of the fishAnd that’s when the real problem surfaced.

“I looked through the literature and found that most of the previous authors who talked about this were basically just looking,” Engelman said. Then he measured the dimensions of several fish skulls and compared them to the proportions of their bodies. It was found that the size and shape of the skull are closely related to the proportions of the body.

when applied to Terelli, this analysis not only excluded the most extreme size estimates, but ignored them all. Engelman wrote in his book A Stady Published in Diversity Magazine.

Engelman’s analysis considered several suspect factors, but ultimately came down to skull height versus width. Fish with longer skulls tend to be more elongated, while fish with shorter skulls have shorter bodies. The relatively short head of Terelli It is suggested that it had a short and broad body, more like a tuna than a shark.