Helicoprion bessonowi

Overview

Helicoprion, meaning "spiral saw," is one of the strangest creatures to ever swim in Earth's oceans. Living approximately 270 million years ago during the Permian period, this bizarre fish is famous for its jaw that looked like a circular saw blade! For over 100 years, scientists couldn't figure out where that weird tooth spiral actually went.

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Taxonomy & Classification

• Class: Chondrichthyes (cartilaginous fish)
• Order: Eugeneodontida
• Family: Helicoprionidae
• Diet: Carnivorous

Helicoprion was related to modern sharks and rays but belonged to an extinct group.

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Physical Characteristics

Size & Build

• Length: 5-8 meters (16-26 feet)
• Weight: 200-450 kg (estimated)
• Body Shape: Similar to modern sharks

The Bizarre Tooth Whorl

The most amazing feature was its spiral tooth arrangement:

• Circular spiral of teeth in the lower jaw
• Oldest teeth in the center, new teeth on the outside
• Looked like a circular saw blade or spiral
• Could have over 150 teeth in the whorl!
• Teeth were never lost—they just kept spiraling inward

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The 100-Year Mystery

Where Did the Spiral Go?

For over a century, scientists argued about the tooth whorl's location:

Wrong Guesses:

• On the forehead like a horn
• On the dorsal fin
• Curled under the lower jaw
• On the tail

The Real Answer (2013):

• CT scans of a skull finally revealed the truth
• The whorl was entirely inside the lower jaw
• Worked like a gear or pizza cutter
• As the jaw closed, teeth rotated backward into prey

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How It Hunted

Buzzsaw Feeding

Helicoprion's unique jaws worked in a special way:

• Jaw closing caused teeth to rotate like a saw
• Perfect for slicing through soft-bodied prey
• Probably ate ammonites (squid-like animals with shells)
• May have also eaten fish and other soft creatures
• Could cut prey in half with its rotating teeth!

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Fossil Evidence

Why It's Mysterious

• Like all sharks, its skeleton was made of cartilage (not bone)
• Cartilage rarely fossilizes
• Only the tooth whorls were preserved
• Scientists had to guess what the rest looked like
• Each new fossil provides more clues

Where Found

Fossils discovered in:

• Russia
• North America (Idaho, Nevada, Wyoming)
• Australia
• Asia
• Shows it lived in oceans worldwide

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The Permian World

Ancient Ocean Life

Helicoprion lived in a world before dinosaurs:

• 250+ million years before T. rex
• Survived until near the Great Dying (largest extinction ever)
• Shared oceans with other bizarre creatures
• No marine reptiles yet—fish ruled the seas

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Cool Facts

• Helicoprion is NOT a shark—it's a related but different kind of fish
• Its teeth kept growing throughout its entire life
• The tooth whorl could be as big as a dinner plate!
• It survived for about 30 million years before going extinct
• Scientists argued about its appearance for over 100 years
• Its name means "spiral saw" in Greek
• No complete skeleton has ever been found!

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Helicoprion reminds us that prehistoric life was far stranger than we can imagine—nature created a fish with a built-in circular saw!