Jaws of the Past: Unveiling 16 Fascinating Prehistoric Sharks

Leave a comment / By: Jerry Young / Updated on: 24th September 2023

The first sharks evolved over 450 million years ago, more than 200 million years before the first mammals appeared. 

Unlike many other animal groups that have since gone extinct, sharks are still among the most abundant animals in Earth’s oceans today, making them one of the oldest living animal groups. 

Prehistoric sharks existed in different fascinating forms, from giant apex predators to bizarre-looking ones with mouths shaped like buzzsaws. 

These different shark species have dominated the seas throughout geologic time, ruling alongside the marine reptiles and other ocean-dwelling predators of the past. 

In this article, we’ll provide an overview of 16 of the most fascinating prehistoric shark species. 

16. Abdounia

Name	Abdounia
Name Meaning	The location of its discovery, the Abdoun region in Jordan.
Pronunciation	Ab-Don-Ni-a
Era	Cenozoic – Paleogene
Classification	Chondrichthyes, Carcharhiniforme & Carcharhinidae
Diet	Carnivorous
Height	N/A
Length	Less than 4 meters (13 feet)
Weight	N/A
Location	Worldwide

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Abdounia was a requiem shark, a relative of popular shark species like the bull and white tip sharks. 

It was one of the earliest members of the requiem shark family 

Abdounia was alive during the Paleogene Period but died off by the end of the Oligocene. 

Abdounia tooth fossils are among the most common tooth fossils found today. 

Fossils of this shark are commonly found in North America, Europe, and Africa, which suggests that the shark’s range was in this region. 

Because it is only known from tooth fossils, not much is known about this shark’s size and appearance. 

It was probably medium-sized, with an average length of less than four meters (13 feet). 

15. Hexanchus

Name	Hexanchus
Name Meaning	Six gills
Pronunciation	Heks-AN-kus
Era	Cenozoic – Present (extant)
Classification	Chondrichthyes, Hexanchiformes & Hexanchidae
Diet	Carnivorous
Height	N/A
Length	5 meters (16.4 feet)
Weight	600 kilograms (1,300 lbs)
Location	Worldwide

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More commonly known as the bluntnose sixgill shark, the Hexanchus is a living fossil because it has been around since the Jurassic Period. 

In fact, fossils of relatives of this shark species have been found in rocks dating back to the Triassic Period. 

The most notable feature of this shark is its blunt, rounded snout. 

It also had six pairs of gill slits, a feature only seen in primitive shark species. 

Most modern sharks have only five-gill slits. 

Hexanchus is a deep-water species that can swim to depths of up to 6000 feet. 

It lives in tropical and temperate waters all over the world. 

14. Scapanorhynchus

Name	Scapanorhynchus
Name Meaning	Shovel snout
Pronunciation	Ska-pan-o-RINK-us
Era	Mesozoic – Late Cretaceous to Paleogene
Classification	Chondrichthyes, Lamniformes & Mitsukurinidae
Diet	Carnivorous
Height	N/A
Length	4.15 to 6 meters (13.6–22 feet)
Weight	N/A
Location	North America, Europe, Asia, and Africa

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Scapanorhynchus belongs to the same family as the modern-day goblin shark and had a very similar appearance.

But this prehistoric fish went extinct in the Miocene Epoch and had several subtle differences that set it apart from the goblin shark. 

The most distinctive feature of the Scapanorhynchus was its long snout which extended well past its jaws. 

The snout was probably useful for navigating the dark waters and catching prey in the deep aquatic ecosystem where this shark lived. 

Despite being just about 4.15 to 6 meters (13.6–22 feet) long, the Scapanorhynchus had oversized teeth that were six centimeters (0.20 feet) long on average. 

13. Somniosus

Name	Somniosus
Name Meaning	Sleepy one
Pronunciation	Suhm-NEE-uh-sus
Era	Cenozoic – Present
Classification	Chondrichthyes, Squaliformes, Somniosidae
Diet	Carnivorous
Height	N/A
Length	7 meters (23 feet)
Weight	400 and 1,400 kg (880 and 3,090 lb)
Location	North Atlantic, Arctic, and Southern Ocean.

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Somniosus is more commonly referred to as the Greenland shark. 

Although it is still alive today, this group of sharks qualifies as a prehistoric shark because it has been around for over 100 million years. 

It is a fascinating creature with an incredible lifespan of more than 400 years for an individual. 

This means the Greenland shark has the longest lifespan of any known vertebrate.

It is also one of the largest living sharks, growing to lengths of about 2.4 to 7 meters (7.9–23.0 feet) on average. 

Somniosus is an apex predator that feeds on other sharks and different types of fish. 

The Somniosus is also a partial scavenger known to feed on carcasses. 

12. Cretoxyrhina

Name	Cretoxyrhina
Name Meaning	Cretaceous sharp nose
Pronunciation	Kree-toh-ZIE-ree-nuh
Era	Mesozoic – Late Cretaceous
Classification	Chondrichthyes, Lamniformes, Cretoxyrhinidae
Diet	Carnivorous
Height	N/A
Length	8 meters (26 feet)
Weight	4.8 tons (10,000lbs)
Location	North America, Europe, and Africa

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The Cretoxyrhina’s nickname, Ginsu Shark, tells you everything you need to know about this prehistoric shark. 

The name refers to the popular Ginsu knife, which the shark’s razor-sharp teeth resemble. 

These bone-shearing teeth were effective in taking down some of the largest animals in the Cretaceous seas, including other notable predators like the mosasaurs, plesiosaurs, and Xiphactinus. 

With a total body length of about eight meters (26 feet), weight of over 4.8 tons, and build similar to modern-day white sharks, Cretoxyrhina was undoubtedly among the most ferocious sharks of the Cretaceous seas. 

11. Otodus

Name	Otodus
Name Meaning	Ear-shaped tooth
Pronunciation	Oh-TOH-dus
Era	Cenozoic – Paleogene
Classification	Chondrichthyes, Lamniformes & Otodontidae
Diet	Carnivorous
Height	N/A
Length	12 meters (40 feet)
Weight	15 tons (30000 lbs)
Location	Europe, North America, Africa, and Asia

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Otodus was a type of mackerel shark that was alive until about 33 million years ago in warm oceans across the globe.

It was a large predatory shark, with some species reaching lengths up to 20.3 meters (67 feet). 

However, most species were within the 11 to 13 meters (36–44 feet) range. 

Given its size, Otodus was probably one of the apex predators of the Paleocene and Miocene epochs.

It preyed on fish, cetaceans, and giant turtles. 

Some teeth fossils of this fish were up to 104 millimeters (4.1 inches) long, effective for biting through large prey. 

Otodus is considered an ancestor of the Megalodon, the largest shark species ever found.

10. Orthacanthus

Name	Orthacanthus
Name Meaning	Straight-spine
Pronunciation	OR-thuh-KAN-thus
Era	Paleozoic – Carboniferous to Permian Period
Classification	Chondrichthyes, Xenacanthida & Orthacanthidae
Diet	Carnivorous
Height	N/A
Length	Up to 3 meters (10 feet)
Weight	100 kg (220 lbs)
Location	Europe, North America, Africa, and Asia

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Orthacanthus was a shark genus that lived in the freshwaters and swamps of North America and Europe from the Upper Carboniferous to Lower Permian periods.

Mature individuals could grow up to three feet in length and were apex predators in their habitat. 

Orthacanthus had a long, eel-like body with relatively short fins. 

It is often compared to the Xenacanthus, another eel-like shark that lived around the same time but was significantly smaller. 

Like the Xenacanthus, the Orthacanthus also had a long spike protruding out of its head which may have served defensive purposes too. 

Name:

9. Ptychodus

Name	Ptychodus
Name Meaning	Folded tooth
Pronunciation	TIE-ko-dus
Era	Mesozoic – Late Cretaceous
Classification	Chondrichthyes, Elasmobranchii & Ptychodontidae
Diet	Carnivorous
Height	N/A
Length	10 meters (33 feet)
Weight	N/A
Location	Europe, North America, and Asia

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Modern-day sharks thrive on fish and other soft-bodied prey. 

But the Ptychodus, a Late Cretaceous shark genus, had a more specialized diet. 

It had rounded teeth instead of the typical triangular teeth of most types of sharks. 

These teeth were modified for crushing the shells of hard-bodied prey such as shellfish, ammonites, and bivalves. 

Ptychodus lived mainly in the Western Interior Seaway, which covered most of North America during the Cretaceous Period. 

Fossils of this prehistoric shark have also been found on other continents. 

It was a large shark that may have reached lengths of up to 10 meters (33 feet) by some estimates. 

8. Xenacanthus

Name	Xenacanthus
Name Meaning	Alien spine
Pronunciation	Zee-nuh-KAN-thus
Era	Paleozoic – Late Carboniferous to Early Permian
Classification	Chondrichthyes, Elasmobranchii & Xenacanthida
Diet	Carnivorous
Height	N/A
Length	1 to 2 meters (3.3–6.5 feet)
Weight	2-5 kilograms (4.4–11 pounds)
Location	Europe, North America, South America, and Australia

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Xenacanthus was a prehistoric shark that lived in freshwater habitats from the Carboniferous to the Permian Period, between 318 to 200 million years ago. 

It was a relatively small shark that measured about one to two meters (3.3 to 6.6 feet). 

Xenacanthus was a predator that fed on fish and other small aquatic creatures. 

This prehistoric shark had a long eel-like body and probably swam like an eel too. 

The most distinctive feature of this shark is the prominent spine that projects from the back of its head. 

The Xenacanthus’ name, which translates as the alien spine, is a reference to this spike. 

The spike on the Xenacanthus’ head was probably venomous and may have protected the small shark from predators. 

7. Cretalamna

Name	Cretalamna
Name Meaning	Cretaceous lamnoid shark
Pronunciation	Kree-tuh-LAM-nuh
Era	Mesozoic – Late Cretaceous
Classification	Chondrichthyes, Lamniformes & Lamnidae
Diet	Carnivorous
Height	N/A
Length	3.5 meters (11 feet)
Weight	N/A
Location	North America, Europe, Asia, and Africa

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Similar in form to modern-day lamniform sharks like great white sharks and thresher sharks, Cretalamna lived from the Early Cretaceous Period to the Eocene Epoch (103 to 46 million years ago).

Although not one of the biggest prehistoric sharks, it is an important species because it is considered the ancestors of the Otodus and Megalodon, two of the largest shark species to have ever lived.

Cretalamna was one of the most widely distributed shark genera in terms of geography and time range. 

It was an active predator that grew to lengths of up to 3.5 meters (11 feet) and may have hunted marine reptiles such as plesiosaurs and mosasaurs.

6. Hybodus

Name	Hybodus
Name Meaning	Hump Tooth
Pronunciation	HY-buh-dus
Era	Mesozoic – Triassic to Early Cretaceous
Classification	Chondrichthyes, Elasmobranchii & Hybodontiformes
Diet	Carnivorous
Height	N/A
Length	1–3 meters (3–10 feet)
Weight	50–100 kilograms (110–220 lbs)
Location	Fossils found globally

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Hybodus was around for over 200 million years, starting from the Devonian Period to the end of the Cretaceous.

This prehistoric shark is well-known in the fossil record, with numerous pieces of skeleton discovered so far. 

One possible explanation for the longevity of this group of sharks is the unique nature of their skeleton. 

Instead of the typical cartilaginous skeleton sharks, the Hybodus’ bone was tough and calcified. 

This also explains why there are so many fossils of this shark around. 

Hybodus measured about six feet in length and weighed between 100 and 200 pounds. 

It had two sets of teeth in its jaw, one for ripping into prey and the other for grinding hard-shelled prey such as mollusks. 

5. Cladoselache

Name	Cladoselache
Name Meaning	Branch Shark
Pronunciation	Klah-doh-SEL-uh-kee
Era	Paleozoic – Devonian
Classification	Chondrichthyes, Elasmobranchii & Cladoselachidae
Diet	Carnivorous
Height	N/A
Length	2.0 meters (6.6 feet)
Weight	5-10 kilograms (11–22 lbs)
Location	North America, Europe, and Australia

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With an existence that dates back to the Late Devonian Period, 385 million years ago, 

Cladoselache is considered the oldest true shark known from the fossil record.

It is similar in shape to modern laminid sharks but isn’t directly related to them. 

Cladoselache lived in freshwater and shallow marine environments and was an active predator. 

Fossils of the Cladoselache are well preserved in rocks. 

They preserve traces of the shark’s body outline, skin, muscle fibers, and even internal organs, which is unprecedented for a shark species from so long ago in the past. 

4. Edestus

Name	Edestus
Name Meaning	Devourer
Pronunciation	E-DESS-tus
Era	Paleozoic – Carboniferous
Classification	Chondrichthyes, Elasmobranchii & Edestidae
Diet	Carnivorous
Height	N/A
Length	4–6.7meters (10–22 feet)
Weight	300–500 kilograms (660–1,100 lbs)
Location	Europe and North America

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Edestus was a cartilaginous fish that lived during the Carboniferous Period about 318 million years ago. 

Also known as the scissor-tooth shark, this marine predator used its rows of sharp teeth on the lower and upper jaws, modified to form curved blades or “whorls” to slash at prey. 

The specialized teeth of Edestus were continuously growing and were sharpened against each other. 

The largest species in the genus grew to lengths of up to 6.7 meters (22 feet), about the same size as a great white shark. 

Edestus is related to the Helicoprion, another prehistoric shark species with jaws modified into whorls. 

3. Stethacanthus

Name	Stethacanthus
Name Meaning	Chest spine
Pronunciation	Steth-uh-KAN-thus
Era	Paleozoic – Carboniferous Period
Classification	Chondrichthyes, Elasmobranchii & Stethacanthidae
Diet	Carnivorous
Height	N/A
Length	Approximately 1-3 meters (3-10 feet)
Weight	4.5–9kg (10-20 lbs)
Location	Fossils found globally

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Stethacanthus is also known as the anvil shark or ironing board shark, a reference to the strange protrusion that jutted out of the back of male individuals of this species. 

The ironing-board-shaped structure was a modification of the Stethacanthus’ dorsal fin. 

The exact function of this peculiar dorsal fin is still not entirely understood, but experts think they probably used them to attach to females while mating. 

Stethacanthus lived from the late Devonian-early Carboniferous (390-320 million years ago). 

Aside from the modified dorsal fin, the rest of the Stethacanthus’ body was otherwise unimpressive.

It was a small bottom feeder with a maximum length of about three meters that survived on small fish and marine invertebrates.

2. Helicoprion 

Name	Helicoprion
Name Meaning	Spiral saw
Pronunciation	HEE-lih-koh-PREE-on
Era	Paleozoic – Permian to Triassic
Classification	Chondrichthyes, Elasmobranchii, Euchondrocephali
Diet	Carnivorous
Height	N/A
Length	5-8 meters (16 to 26 feet)
Weight	500-700 kilograms (1,100-1,500 lbs)
Location	North America, Europe, and Asia

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Also known as the buzz-saw killer, Helicoprion was a prehistoric shark-like fish with a bizarre appearance. 

The only part of this shark known to paleontologists is its distinctive spiral-shaped tooth whorls. 

This modification of the shark’s lower jaw was effective in killing soft-bodied animals. 

It may have also helped them deshell hard-bodied prey such as nautiloids and ammonoids that were common in the Triassic seas. 

Helicoprion evolved during the Permian and was alive till the early Triassic Period.

Fossils of this prehistoric fish have been found in North America, Europe, and Asia. 

The Helicoprion reached lengths of about five to eight meters, around the same size as modern basking sharks.

1. Megalodon 

Name	Megalodon
Name Meaning	Big tooth
Pronunciation	MEG-uh-loh-don
Era	Cenozoic – Neogene Period
Classification	Chondrichthyes, Lamniformes & Otodontidae
Diet	Carnivorous
Height	N/A
Length	15–18 meters (49–59 feet)
Weight	55–77 tons (110,231-154,324 lbs)
Location	Fossils found globally, primarily in coastal areas.

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With an estimated length of up to 60 feet, the Megalodon was the largest shark ever found and also one of the most powerful predators to have ever lived. 

For context, the biggest great white sharks today grow to an average length of just 20 feet, just small enough for a juvenile Megalodon to feast on. 

The giant shark lived in warm coastal waters all over the world from the Miocene to Pliocene Epoch between 23 and 3.6 million years ago.

Fossil evidence suggests it had a robust jaw with enormous teeth, indicating a powerful bite. 

Each tooth had a diagonal length of at least 180 millimeters (7.1 inches), the largest of any shark species. 

The Megalodon’s diet would have included various large prey such as whales, seals, and giant sea turtles. 

Sources

• https://ocean.si.edu/ocean-life/sharks-rays/megalodon
• https://australian.museum/learn/animals/fishes/helicoprion/
• https://en.wikipedia.org/wiki/Stethacanthus
• https://eartharchives.org/articles/weird-fossil-of-the-week-edestus/index.html
• https://en.wikipedia.org/wiki/Hybodus
• https://australian.museum/learn/animals/fishes/xenacanthus/
• https://australian.museum/learn/animals/fishes/otodus-megalodon/
• https://en.wikipedia.org/wiki/Cretoxyrhina
• https://www.zmescience.com/feature-post/natural-sciences/animals/fish/the-greenland-shark-a-mysterious-and-fascinating-creature-of-the-deep/
• https://australian.museum/learn/animals/fishes/bluntnose-sixgill-shark-hexanchus-griseus/
• https://en.wikipedia.org/wiki/Abdounia
• https://en.wikipedia.org/wiki/Orthacanthus