Dunkleosteus terrelli

Overview

Dunkleosteus was one of the most terrifying predators to ever swim in Earth's oceans—and it lived over 358 million years ago, long before dinosaurs existed! This armored fish had one of the most powerful bites of any animal ever, capable of slicing through virtually anything in its ancient sea.

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Taxonomy & Classification

• Class: Placodermi (armored fish)
• Order: Arthrodira
• Family: Dunkleosteidae
• Diet: Carnivorous (hypercarnivore)

Dunkleosteus was a placoderm—an extinct group of armored fish that ruled the Devonian seas.

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Physical Characteristics

Size & Build

• Length: 4.1-10 meters (13-33 feet)
• Weight: 950-1,200 kg (1-1.3 tons) or possibly more
• Head Shield: Up to 1 meter long!

Armored Tank of the Sea

• Heavy bone plates covered head and front body
• Plates were 5 cm (2 inches) thick!
• Made of a material called cosmine (similar to our tooth enamel)
• Rear body was unarmored and flexible for swimming

The Killer "Teeth"

Dunkleosteus didn't have true teeth:

• Instead had self-sharpening bone blades
• Upper and lower jaws formed giant shears
• Blades continually wore against each other, staying razor-sharp
• Could cut through anything—even other armored fish!

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The Incredible Bite

Most Powerful Bite Ever?

Dunkleosteus had an unbelievable bite:

• Bite force: 5,000-7,400 newtons (1,100-1,650 lbs of force)
• Among the strongest bites of any fish ever
• Could bite with the force concentrated on a single point!
• Jaws could open and snap shut in 1/50th of a second
• Created suction to pull prey into its mouth

Bite Comparison

Animal	Bite Force
Great White Shark	~4,000 N
Dunkleosteus	5,000-7,400 N
Saltwater Crocodile	~16,000 N
T. rex	~35,000-57,000 N

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Hunting & Diet

Apex Predator

Dunkleosteus likely ate:

• Other fish (including armored ones!)
• Sharks (yes, it ate sharks!)
• Cephalopods (squid relatives)
• Basically anything it could catch

Evidence of Ferocity

• Fossil Dunkleosteus bones show bite marks from other Dunkleosteus!
• Probably cannibalistic when hungry
• Fossils show regurgitated fish bones—it couldn't digest everything!

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The Devonian World

The Age of Fishes

Dunkleosteus lived during a special time:

• Called the "Age of Fishes"
• 358-382 million years ago
• No dinosaurs yet (they came 150 million years later!)
• Fish dominated both fresh and salt water
• Seas were warm and shallow

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Extinction

End of an Era

Dunkleosteus and all placoderms went extinct about 358 million years ago:

• Devonian extinction event
• Climate changed dramatically
• Seas became low in oxygen
• Sharks and bony fish took over
• All armored placoderms disappeared

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Fossil Discoveries

Famous Finds

• First described in 1956
• Named after David Dunkle, a paleontologist
• Many fossils found in Ohio, USA (Cleveland Shale)
• Also found in Europe, Africa, and Morocco
• Only head and front armor usually preserved

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Cool Facts

• Dunkleosteus could open and close its jaws in just 1/50th of a second!
• It's the state fossil of Ohio
• Could probably bite a great white shark in half
• Some scientists think it was slow-moving despite its power
• Its bone blades sharpened themselves like a self-sharpening knife
• Lived 100 million years before the first dinosaurs!
• We only have fossils of its armored parts—the rest was soft and decayed
• Babies were probably born already armored

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Dunkleosteus was the nightmare of the Devonian seas—an armored monster with a bite so powerful it could crush almost anything in its path!