Extinct sharks are a fascinating chapter of our planet’s history, often overshadowed by the story of dinosaurs. They are the long-gone species that once roamed the oceans, with some dating back to before the age of the dinosaurs.
This guide is designed to dissect the veil of time, offering a comprehensive overview of these ancient predators, their evolution, and the factors that led to their extinction.
As we explore the world of extinct sharks, we will also take a look at some of the most famous and fascinating species that have ever lived.
Factors Contributing to Shark Extinction
Numerous factors are contributing to the looming threat of shark extinction. The underlying causes primarily stem from destructive human activities that significantly impact and disrupt shark populations.
- Overfishing: This is the primary reason sharks are on the brink of extinction. Overfishing involves capturing too many fish from one area, depleting the population faster than it can replenish itself.
- Bycatch: Sharks are often unintentionally caught in fishing nets and longlines while other species are being targeted. These trapped sharks usually don’t survive.
- Finning: The demand for shark fins, especially for culinary purposes like shark fin soup, has led to this cruel and unsustainable practice where sharks are killed just for their fins.
- Climate change: As global temperatures rise, ocean dynamics are changing. These changes are causing shifts in prey distribution, altering shark migratory and breeding patterns.
The Most Notable Extinct Shark Species
1. The Megalodon (Otodus megalodon)
Likely the most famous extinct shark on this list, the Megalodon tops our chart. This monstrous creature lived approximately 3.6 to 23 million years ago.
It was by far the largest shark species that has ever existed, with estimates suggesting it could grow anywhere between 15 to 20 meters long.
The Megalodon’s teeth, which have been discovered across the globe, indicate its broad diet, from whales to large fish.
2. The Helicoprion (Helicoprion bessonowi)
The Helicoprion is well-known for its unique ‘buzzsaw’ arrangement of teeth. Fossil records suggest that these amazing creatures lived about 290 million years ago during the Early Permian era.
The exact placement and purpose of their strange set of teeth, however, are still disputed among scientists.
What’s certain is that their distinctive jaw structure, unlike anything we see in current shark species, contributes greatly to their mystique.
3. The Stethacanthus (Stethacanthus altonensis)
Dwelling in the oceans of the Late Devonian to Early Carboniferous period, roughly 360 to 320 million years ago, the Stethacanthus was a shark of peculiar appearance. Its main distinguishing feature was a flat, anvil-like dorsal fin that is thought to have acted as a mating display. Its small size (about 70cm in length) contrasted the bizarre enormity of its fin structure.
4. The Cretoxyrhina (Cretoxyrhina mantelli)
Fondly known as the “Ginsu Shark,” this formidable predator lived during the Late Cretaceous period, about 100 to 82 million years ago.
An impressive beast, the Cretoxyrhina grew up to 7 meters long. Well-preserved fossil records reveal its large, razor-like teeth, reminiscent of a kitchen knife set, thus earning its nickname, the Ginsu Shark.
5. The Edestus (Edestus giganteus)
This unusual extinct shark was part of the early Carboniferous period, existing around 300 million years ago.
One distinctive feature of the Edestus was its weird teeth that were shaped like scissors which did not shed as they wore out, unlike other sharks. This resulted in a large, curved cutting edge in their jaws.
6. Scapanorhynchus (Scapanorhynchus texanus)
This is an ancestor of the modern goblin shark, having lived during the Late Cretaceous period around 85 million years ago. Scapanorhynchus was likely a deep-water predator, similar to its freakish-looking descendent.
With its elongated snout and large, protruding teeth, the Scapanorhynchus was built for deep-sea hunting.
7. Cladoselache (Cladoselache fyleri)
From the Devonian period, the Cladoselache is one of the oldest known shark species, dating back 370 million years.
Interestingly, this shark was almost completely scaleless except near its fins, a striking ‘modern’ feature. The Cladoselache also had a streamlined body for fast predatory action.
8. Xenacanthus (Xenacanthus decheni)
Living from the late Devonian to the Triassic, the Xenacanthus was a freshwater shark with a distinct, elongated dorsal fin and a single ‘fang’ projecting from the top of its skull.
Its unique adaptation to freshwater environments separates the Xenacanthus from most other shark species which were (and are) largely marine.
9. Ptychodus (Ptychodus mortoni)
This extinct shark swam in the seas of the Late Cretaceous period, approximately 89 million years ago. Not a massive predator like some other extinct sharks, the Ptychodus had pavement-like teeth suited to crushing shells.
It was likely a bottom-dwelling shark feeding on mollusks and crustaceans.
10. Hybodus (Hybodus Fraasi)
Living in the waters from Late Permian to Late Cretaceous, the Hybodus was a successful genus with multiple species.
What’s fascinating about Hybodus is how this shark species managed to survive several mass extinction events, including the Permian-Triassic extinction.
11. Carcharocles angustidens
Predating the Megalodon, Carcharocles angustidens lived during the Oligocene Epoch roughly 33 to 22 million years ago. This substantial shark is notable due to its considerable size, potentially reaching up to 9.1 meters in length.
12. Falcatus falcatus
The Falcatus falcatus is an extinct shark from the Carboniferous period, living approximately 323 to 316 million years ago. This small shark grew up to about 25 centimetres in length.
What makes this shark significant is the discovery of sexual dimorphism where male Falcatus individuals bore a pronounced spine extending over their heads, whereas females did not.
This was the first time scientists could determine the gender of an extinct shark.
What Did Extinct Sharks Eat?
Extinct sharks, much like their modern counterparts, were apex predators in the ocean’s ecosystems. Their diets typically included a variety of prey, ranging from smaller fish and invertebrates to larger marine mammals, depending on the shark’s size.
Some of the largest species, such as the megalodon, may have hunted whales, as suggested by bite marks found on fossil whale bones.
The dietary habits of these extinct creatures were influenced considerably by their physical attributes, with larger sharks being capable of taking down sizable prey due to their formidable jaws and robust teeth.
On the other hand, some extinct shark species were not giant predators but rather adapted to a different kind of sustenance. These sharks likely fed on small fish, crustaceans, and cephalopods.
Ocean bottom dwellers, such as the smaller shark species, would have had diets that chiefly consist of organisms found in benthic environments.
The availability of food sources and the competition for those resources would have also played a significant role in their eating habits. Their teeth’s morphology and wear patterns often offer clues to paleontologists about their diet and feeding behavior.
Preventative Measures to Protect Current Shark Species
In addressing the crucial task of protecting current shark species, it’s imperative to adopt a series of preventative measures that aim to safeguard these magnificent creatures for future generations.
Sharks play a vital role in maintaining the health of ocean ecosystems, balancing marine life populations, and ensuring the overall health of our oceans.
Here are ways to educate and facilitate the protection of shark populations worldwide:
- Enforce and Strengthen Fishing Regulations: It’s critical to regulate fishing practices to prevent overfishing and illegal catch. By-catch, the accidental capture of non-target species, often results in shark deaths. Implementing stricter regulations and monitoring fishing activities can significantly reduce these incidents.
- Support Shark Sanctuaries: Establishing and maintaining areas where sharks are protected from fishing and hunting helps to ensure their survival. These sanctuaries provide safe havens for sharks to breed and thrive, away from human threats.
- Advocate for Sustainable Seafood Choices: Consumers play a substantial role in conservation by choosing seafood from sources that do not harm sharks or their habitats. Look for certification labels that indicate sustainable practices, and avoid seafood known to negatively impact shark populations.
- Educate the Public on the Importance of Sharks: Awareness and understanding are fundamental in changing public perceptions of sharks. Education campaigns that highlight the crucial role sharks play in marine ecosystems can foster increased support for their protection.
- Support Research and Conservation Efforts: Funding and participating in research and conservation projects can lead to better understanding and protection strategies for sharks. These efforts are essential in developing effective policies and practices to conserve shark populations.
By taking these steps, we can work together to mitigate the risk factors threatening shark species and ensure their presence in our oceans for years to come. Remember, the survival of sharks is closely linked to the health of the ocean environment, reinforcing the importance of these protective measures.