| Name | Dunkleosteus | Diet | Carnivorous |
| Name Meaning | Dunkle’s-bone | Height | N/A |
| Pronunciation | Dunk-lee-owe-stee-us | Length | 4.1-10 meters (13.5-33 feet) |
| Era | Paleozoic – Devonian Period | Weight | 1-4 metric tons (1.1-4.4 short tons) |
| Classification | Placodermi, Arthrodira & Phlyctaenioidei | Location | Europe, North America, Morocco |
Dunkleosteus Pictures
The Dunkleosteus
Imagine a large fish with armored plates on its head and thorax, a blade-like jaw, and a bite force stronger than that of hyenas and tigers – that’s the Dunkleosteus!
This large arthrodire placoderm was widely distributed in the Late Devonian seas.
It lived approximately 382-358 million years ago and is thought to have been an apex predator thanks to its strong bite force, agility, and speed.
This fish likely lived in deeper waters, with access to various prey to satisfy its dietary needs.
Although many aspects of its appearance, behavior, and reproduction remain a mystery, what has been discovered about the Dunkleosteus until today is still fascinating!
So, don’t hesitate to keep reading, as we’ve gathered quite some information about the Dunkleosteus!
Physical Characteristics
Since the Dunkleosteus is primarily known from fossilized frontal sections, scientists aren’t entirely sure of this creature’s overall appearance.
Many Dunkleosteus reconstructions are based on what is known about smaller arthrodires which is why exact details remain debatable and unclear.
Nevertheless, it is now widely accepted that the Dunkleosteus is among the largest placoderms.
The type species, Dunkleosteus terrelli is described based on the largest specimens that had a length between 4.1 and 10 meters (13.5-33 feet).
These numbers, however, are still highly debated.
For example, a study shows that the largest Dunkleosteus individuals didn’t exceed 4.1 meters (13.5 feet) long, and the average length was approximately 3.3-3.5 meters (10.8-11.5 feet).
Other studies propose greater lengths – 6.88-8.79 meters (22.6-28.8 feet) for D. terrelli.
Weight estimations have also been long debated as well, with some scientists calculating that a D. terrelli measuring 4.6 meters (15 feet) long weighed 665 kilograms (1,466 pounds).
In contrast, others argued for 950-1,200 kilograms (2090-2650 pounds) for a 3.4-meter (11.2 feet) long individual.
As such, it is quite difficult for us to provide a precise answer regarding this prehistoric creature’s size and weight.
We can only hope that future paleontological expeditions will reveal other fossils carrying additional details.
Based on what is known about arthrodire placoderms, here’s what we can say about the Dunkleosteus:
- It had articulated armored plates on the head and thorax.
- The rest of the body was either naked or covered in scales.
- It had a movable joint on its neck.
- It didn’t have teeth. Instead, it had blade-like jaws.
- A bony ring covered its eye sockets.
Some sources mention that the Dunkleosteus wasn’t covered in scales and had a powerful tail similar to that of modern sharks.
Habitat and Distribution
Dunkleosteus fossils were recovered from multiple locations in different parts of the world. These locations include:
- Huron and Cleveland Shale of Ohio
- The Conneaut of Pennsylvania
- Chattanooga Shale of Tennessee
- Lost Burro Formation, California
- Ives Breccia of Texas
- Belgium
- The Atlas Mountains, Morocco
- The Frasnian Rhinestreet Shale of New York
- The Kettle Point Formation, Ontario
- Missouri
- Bilovo Formation, Tver Region, Russia
In short, the Dunkleosteus was widely distributed in the Devonian seas and was likely present in many other regions besides the ones paleontologists had already discovered.
It is well known that the Devonian featured high sea levels, and even much of the land was covered by shallow seas, so the Dunkleosteus most likely had enough space to move around and kill anything it stumbled upon, as ferocious as it was!
The Devonian was also abundant in reefs that were either microbial or coral-stromatoporoid.
Since the Dunkleosteus lived during the Late Devonian, the reefs were likely predominantly coral-stromatoporoid, meaning they were built up by stromatoporoids, which were coral-like sea sponges.
The exceptionally high sea levels ensured a warm climate, enhancing a complete land flora transformation.
This transformation, often called the greening of the land, included the development of roots, seeds, and water transport systems.
This likely led to a cooler climate, which might have, in turn, led to the extinction event.
At least, this could have been one of the many possible causes.
Behavior and Diet
The Dunkleosteus is often regarded as a superpredator of the Late Devonian seas.
Considering its huge size, armored body, and blade-like jaws, this isn’t in the least surprising.
However, its true power stems from the fact that it could rapidly open and close its mouth and had quite a powerful bite!
Studies show that the Dunkleosteus had an impressive bite force for a fish.
The maximum bite force was estimated at approximately 4,400 N at the jaw tip and 5,300 N at the rear dental plates – that is, for large individuals.
Other studies showed even higher numbers.
Fossil evidence shows that Orodus teeth were found in association with Dunkleosteus remains.
Paleontologists, however, suggested the teeth might have been regurgitated by the Dunkleosteus, meaning it fed on that Orodus.
An Orodus was a large cartilaginous fish, reaching 2 meters (7 feet) long.
It was a fast-swimming pelagic fish, and it lived neither too close to the shore nor too close to the bottom of the sea.
If the Dunkleosteus did actually feed on Orodus fish, it was not only armored and strong but also fast enough, contrasting with the first theories suggesting it was a slow swimmer.
Apart from this, little fossil evidence associates the Dunkleosteus with other types of prey.
Still, scientists believe it could have eaten anything it wanted, including other large placoderms, as its bite force was strong enough to penetrate the strong, protective armor.
Life Cycle
The reproductive behavior of Dunkleosteus remains a mystery because no fossil evidence can confirm whether they reproduced by laying eggs or by giving birth live.
It is well known that while most fishes reproduce by laying eggs, some are viviparous, meaning they are livebearers.
It is poorly known, however, that placoderms were among the earliest vertebrates that reproduced through live birth, meaning they adapted to internalizing egg fertilization.
While this has been proven for other placoderms, we cannot confirm whether the Dunkleosteus was also viviparous.
After baby Dunkleosteus were born (or hatched), they likely had a different lifestyle and feeding behavior than adults.
It is thought that juveniles lived in shallower waters, as fossils were recovered from closer to the shore, with adults remaining full-time in deep waters.
It has also been suggested that juveniles might have been almost as strong as adults, that is, in terms of bite force.
Evolution and History
Members of the Placodermi class are thought to have diverged from sharks and bony fishes approximately 400 million years ago.
The first placoderm fossils date from the Silurian; the Shimenolepis, an antiarch, was the first officially described placoderm.
During the Devonian, placoderms became quite abundant in freshwater and saltwater habitats.
The Dunkleosteus is part of the Arthrodira group of placoderms, which includes numerous diverse species – some being apex predators, others being bottom dwellers.
The first Dunkleosteus fossils were discovered in 1867 on Lake Erie cliffs, Ohio.
In 1873, the fossils were attributed to Dinichthys herzeri, which was subsequently named Dinichthys terrelli after Jay Terrell, who had discovered the fossils.
Unfortunately, most of Terrell’s fossils were destroyed in a fire.
Following other discoveries, fossils belonging to this creature were attributed to Dunkleosteus in 1956.
This genus was considered closely related to the Dinichthys until 2010, when a phylogenetic study concluded they were, in fact, part of separate clades.
As such, the Dunkleosteus, alongside the Eastmanosteus, Heterosteus, Golshanichthys, and others, is now part of the Dunkleosteidae family.
Nevertheless, this classification is still debated.
The type species of the genus is Dunkleosteus terrelli and includes the largest members discovered in Ohio, Tennessee, California, Texas, and some parts of Europe.
Over the years, at least nine other species were described, which are:
- D. belgicus – considered a nomen dubium, meaning a doubtful species, as some scientists argue that the fossils actually belong to the Ardennosteus
- D. denisoni – much smaller than a typical Dunkleosteus
- D. marsaisi – specimens found in the Atlas Mountains of Morocco
- D. magnificus – originally described as Dinichthys magnificus
- D. missouriensis – known from fragments recovered in Missouri
- D. newberryi – originally described as Dinichthys newberryi
- D. amblyodoratus – known from fragments discovered in Ontario’s Kettle Point Formation
- D. raveri – small specimens, probably not longer than 1 meter (3.2 feet); they also likely had relatively large eyes
- D. tuderensis – discovered in northwest Russia’s Bilovo Formation
However, as often happens with prehistoric animal species, many of the above are considered dubious or synonymous.
Interactions with Other Species
The Dunkleosteus was among the world’s largest armored fish; without a doubt, it was an apex predator in its habitat.
Not only did it feed on anything its stomach wished, but it was also very difficult, almost impossible, to kill.
If anything, only other Dunkleosteus individuals could inflict bites on this ferocious predator.
During the Late Devonian, the seas were abundant in placoderms, and among the most common were Bothriolepis individuals, although they were much smaller than the Dunkleosteus.
Other marine creatures included:
- Cladoselache, an early chondrichthyan related to modern sharks, which were also predators and likely competed with the Dunkleosteus in speed and agility.
- Titanichthys, another placoderm similar to the Dunkleosteus, except that it had small mouth plates adapted for filter feeding
- Materpiscis, another placoderm and the first known viviparous vertebrate
- Rhizodonts, meaning lobe-finned fish and among the largest known freshwater fish
Cultural Significance
Contrary to what one may think, the Dunkleosteus is quite popular in books, movies, and video games. Here are some of its most notable appearances:
- Dinotopia
- Hungry Shark (mobile game)
- Sea Monsters (documentary)
- E.V.O: Search for Eden (video game)
- Ecco the Dolphin (video game)
- ARK: Survival Evolved (video game)
- Jurassic Park Builder (video game)
- Jurassic World: The Game (video game)
The Dunkleosteus is also of significant interest among scientists fascinated by its strength and lifestyle.
Despite being such an important creature in outlining our world’s evolutionary history, the members of the genus are still poorly known.
We’re eagerly awaiting new studies that potentially reveal groundbreaking information about these powerful fish, especially their reproductive behavior and feeding techniques.
Conclusion
Having lived approximately 382-358 million years ago during the Late Devonian, the Dunkleosteus was widely distributed across our planet’s seas, where it was a ferocious apex predator.
Although very little is known about its appearance, and even its maximum length is often debated, one thing is clear – the Dunkleosteus was one of the world’s largest placoderms and had such a strong bite force that only a few extant animals could surpass it!
FAQs
Is Dunkleosteus bigger than Megalodon?
The Megalodon was a mackerel shark and was, without a doubt, much larger than the Dunkleosteus, reaching a maximum length of 20.3 meters (67 feet).
What killed the Dunkleosteus?
The Dunkleosteus went extinct during the environmental catastrophes of the Late Devonian.
More precisely, the Dunkleosteus and other placoderms likely disappeared after the Hangenberg event, also known as the end-Devonian extinction.
Sources:
- https://en.wikipedia.org/wiki/Dunkleosteus
- https://www.mdpi.com/1424-2818/15/3/318
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5723140/
- https://web.archive.org/web/20171107014026/http://projects.fieldmuseum.org/sites/default/files/DunkPaleoBio.pdf
- https://ucmp.berkeley.edu/devonian/devonian.php
- https://en.wikipedia.org/wiki/Bothriolepis
- https://en.wikipedia.org/wiki/Evolution_of_fish#Devonian:_Age_of_fishes
- https://en.wikipedia.org/wiki/Devonian
- https://www.livescience.com/43596-devonian-period.html
- https://natmus.humboldt.edu/exhibits/life-through-time/visual-timeline/devonian-period
- http://bioweb.uwlax.edu/bio203/f2013/peters_sadi/reproduction.htm
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