Dunkleosteus: "The Destroyer" of the Devonian Period

In the depths of the ocean hundreds of millions of years ago, there existed a carnivorous fish with fang-like teeth and a massive skull known as Dunkleosteus. With its stout body and fierce appearance, this Devonian fish truly deserves the nickname “the destroyer” of the ancient age.

Dunkleosteus Fish.

In the latter half of the 19th century, humanity began to discover a large number of fossils from various ancient species, leading to the development of paleontology in the United States. Many strange fossils were found in Tennessee and Wyoming. In 1868, John Newberry established the genus Dinichthys based on the fossilized skull and lower jaw (AMNH 81), with the type species being Dinichthys herzeri.

The massive skull of Dunkleosteus.

For a long time after the naming of the genus Dinichthys, most of the giant ancient fish found in North America were classified within this genus, and it was considered a “catch-all” in the field of animal taxonomy.

In 1956, paleontologist Jean Pierre Lehman discovered that the fish known as Dinichthys terrelli from studies dating back to 1873 was a completely new species, distinct from the Dinichthys genus. He thus renamed and reclassified this fish as Dunkleosteus, belonging to the “Dunkle” genus.

To date, at least 10 species within the Dunkle (Dun) genus have been discovered, with the type species being Dunkleosteus terrelli. Most Dunkleosteus fossils have been found in the United States, North America, and Europe. The face of the Dunkleosteus is striking, featuring a skull shape and extremely fearsome teeth.

The Dunkleosteus face is striking with its skull shape and fearsome teeth.

Dunkleosteus is an extinct genus of placoderm fish that existed during the late Devonian period, approximately 380–360 million years ago. Some species, such as D. terrelli, D. marsaisi, and D. magnificus, are among the largest placoderm fish ever to have lived on Earth.

Dunkleosteus was a relatively large prehistoric carnivorous fish. There was much debate about the true size of this fish; many believed it could reach lengths of over 10 meters. However, through analysis and reconstruction of its body from the fossil samples found, it has been determined that the maximum length of Dunkleosteus was 6 meters and it weighed nearly 1.5 tons.

Size comparison of Dunkleosteus with a human.

Dunkleosteus was an “armored fish.” Its head and neck were covered by a thick bony armor. This characteristic allowed its fossils to often preserve most of the head and neck.

Covering this armor was a shiny skin, with a pair of eyes situated on either side of its head and incredibly large, sharp teeth visible from the outside.

Though it may appear to have teeth, in reality, this fish did not have teeth; what we see and consider teeth are essentially parts of its bony armor.

In reality, this fish did not have teeth.

Jaw structure of Dunkleosteus.

Based on the shape of ancient fossils and skulls, this fish had a higher back, and its body was likely very stout, with a large, powerful tail at the rear. Its robust body, terrifying biting power, and sturdy armor made Dunkleosteus a true armored vehicle within the ocean.

Dunkleosteus is considered one of the earliest jawed vertebrates in Earth’s history.

Dunkleosteus lived during the late Devonian period from 380 to 360 million years ago—considered the golden age of fish. The prosperous development of large carnivorous fish is also seen as a highlight of this era.

Fish with similar skull and jaw structures also appeared quite abundantly, but Dunkleosteus is still regarded as one of the earliest jawed vertebrates in Earth’s history. The bite force of this species is equivalent to 5 tons. But that’s not all: certain parts of its jaw had a bite force of approximately 40 tons per square inch, which is astounding.

With such a bite force, you might wonder, “Could Dunkleosteus defeat a great white shark?” According to experts, it could.

Mark Westneat is one of the ichthyology experts at the Field Museum in Chicago, Illinois—one of the museums showcasing Dunkleosteus fossils. In an interview with Live Science, he expressed his belief that a Dunkleosteus could have outmatched a 6-meter-long great white shark. His conviction is based on shark jaw models created by him and Philip Anderson, head of the project.

Anderson, who works in the Department of Geophysical Sciences at the University of Chicago, also claimed that Dunkleosteus destroyed everything in its environment. Many scientists and paleontologists view Dunkleosteus terrelli as an apex predator, which aptly describes its power. It was one of the first predatory species and remained so until its extinction.

Along with its extremely aggressive nature, this fish is regarded as the top predator in the marine food chain of its time. Dunkleosteus is also considered a heavyweight killer on Earth since the beginning of the formation of vertebrate creatures. With its extraordinarily unique anatomy, its head and chest were covered with armor-like bony plates, making Dunkleosteus a terror to sharks and many other prehistoric marine creatures.

This species has a bite force equivalent to 5 tons.

Research shows that Dunkleosteus had the strongest jaws of any marine creature ever, rivaling the strength of T. rex and modern crocodilians. “Dunkleosteus could eat anything in its environment“, said Philip Anderson, the lead researcher at the University of Chicago.

Fossils were found with many fish bones, and a part of its diet included remnants of other fish species. Scientists suggest that Dunkleosteus often regurgitated the bones of its prey rather than completely digesting them. Dunkleosteus was a ferocious fish, capable of eating anything it encountered while hunting, from small fish, large fish, and sharks, to even its own kind.

Dunkleosteus often regurgitated the bones of its prey rather than completely digesting them.

Dunkleosteus had a mechanism connecting four parts of its jaw between the skull, the gill cover, lower jaw, and the jaw muscles linking together. These joints moved flexibly, allowing both jaws to achieve high speeds when opening and closing. They could open their jaws in 20 thousandths of a second and complete the entire opening and closing process in about 50-60 milliseconds. Dunkleosteus used its jaw muscles to suck in food, assist in capturing prey, and generate a powerful bite force when closing its jaws. The pressure produced was so great that it could pierce or shatter through skin or armor, making Dunkleosteus the most formidable predator of the ocean at that time.

For millions of years during the Devonian period, Dunkleosteus was the dominant marine creature in the ocean world. Scientists say that this terrifying creature was the largest fish in the ocean during the Devonian period. With its reconstructed shape, it resembles an armored tank, ready to attack its intended prey.