Discover an Ancient Shark That Looked Like an Eel And Lived in The Swamps of North America

What we now call North America was the embodiment of wilderness a million years ago. We can only dream about learning about every creature that lived in or crossed the area! However, fossil records show that sharks were pretty common there. We’ve researched and found some incredible facts about an ancient shark with an elongated, eel-like body that went extinct millions of years ago! What are they called, and what’s so special about them? Let’s find out!

What Are Orthacanthus Sharks?

Orthacanthus is a genus of sharks that went extinct during the lower Permian, meaning around 250 million years ago. It was part of the extinct Orthacanthidae family and consisted of freshwater xenacanthid carnivorous sharks living in Europe and North America.

If you’re wondering what xenacanthid means, here’s the answer! The term refers to the Xenacanthida order of extinct shark-like elasmobranchs, meaning cartilaginous fish like sharks, sawfish, or rays.

Orthacanthus sharks inhabited swamps and bayous (bodies of water found in flat, low-lying areas) and were apex predators in their habitats.

The genus is also called Diplodus, Dittodus, and Didymodus and consists of the 12 following species:

• Orthacanthus
• Orthacanthus arcuatus
• Orthacanthus buxieri
• Orthacanthus compressus
• Orthacanthus donnelljohnsi
• Orthacanthus gibbosus
• Orthacanthus gracilis
• Orthacanthus milleri
• Orthacanthus minor
• Orthacanthus platypternus
• Orthacanthus pustulosus
• Orthacanthus texensis

These species may differ in terms of tooth size and form, dorsal spine, denticles, and distribution. For instance, Orthacanthus texensis and Orthacanthus compressus have larger teeth than the other species. Moreover, their tooth bases are wider than other sharks’ tooth bases, which are often larger rather than wider. In turn, these two can be differentiated by the basal tubercle, which is more pronounced in Orthocanthus compressus.

Besides the species differences, fossil records show that young and adult sharks in this extinct genus could be easily distinguished from each other. Their teeth contain essential information about their age, species, and sexual dimorphism.

Some sources state these sharks were approximately 10 feet long. However, fossil discoveries indicate that some might have reached 30 feet!

How Were Eel-like Sharks Discovered, and Where Did They Live?

Fossils belonging to sharks in the Orthacanthus genus were first discovered in the United Kingdom in Leeds, North Wales, Dudley, Edinburgh, and Carluke.

Over the years, fossil records showed that Orthacanthus texensis and Orthacanthus platyptemus lived in Texas during the Lower Permian, while Orthacanthus compressus inhabited Nebraska during the Upper Pennsylvanian. Archeological discoveries indicated that the Texas species came from Orthacanthus compressus, as they retained tooth information from the latter.

Even if it’s generally considered that Orthacanthus sharks primarily inhabited swamps, further research indicates that smaller specimens preferred small ponds and stream channels. At the same time, adults roamed in the depths of rivers and lakes and in marginal marine areas.

Stating that they lived in these regions for the rest of their lives would be impossible since records show that these sharks were prone to changing their habitats and diets depending on their growth rates.

What’s the Oldest Orthacanthus Fossil Specimen?

[Image needed. – Caption: The oldest specimen of an Orthacanthus shark is between 407 and 393 million years old.]

The oldest specimen of an Orthacanthus shark is between 407 and 393 million years old. It was found in New Brunswick, Canada, and dates from the Emsian. Later on, besides the specimens found in North America, archeologists discovered others in the United Kingdom, France, and Poland.

Were Eel-like Sharks Cannibals?

Recent fossil discoveries show that adult Orthacanthus sharks ate their juvenile sharks. The discovery is based on an adult poop fossil that contained baby shark teeth. It was discovered in New Brunswick, Canada, in the Minto Coalfield. Scientists are convinced it belonged to an Orthacanthus because these sharks had distinctive corkscrew rectums.

So why did they eat their young? No one knows for sure. However, researchers believed that marine fishes moved to freshwater swamps during the Carboniferous Period, and the sharks, trying to protect their young, moved to inland waterways. Since food might’ve been scarce in those waters, they ended up eating the baby sharks.

Aodhán Ó Gogáin, a Ph.D. candidate in the School of Natural Sciences and the one who made the discovery, stated that previous records showed that these eel-like sharks fed on other fish and amphibians, but none indicated they ate their own!

He also said that Orthacanthus sharks resembled bull sharks in their ability to travel from shallow areas to coastal swamps and vice versa. This might’ve played an essential role in the evolution of the world’s freshwater population.

Did These Sharks Have Predators?

We’ve already established that Orthocanthus sharks were considered apex predators. However, fossil discoveries showed that there was something even bigger roaming in ancient waters that could feed on these large sharks! A shark skeleton of a half-eaten shark, meaning a partial torso and head of a large specimen, demonstrates something that killed and ate it! However, what creature did this remains unknown.

The fossil was discovered years ago, before the 1980s, but was prepared only recently and is now for sale, the price being $29,500.

Are There Extant Ancient Sharks?

Yes, many ancient shark species survived till the present times. One of the most common is the nurse shark, scientifically called Ginglymostoma cirratum. These sharks have inhabited Earth since the Albian age, meaning they’ve been around for approximately 100 million years! Even though the IUCN lists the species as vulnerable, it’s still amazing they’ve survived for so long! Another extant species in the Ginglymostoma genus is the Pacific nurse shark (Ginglymostoma unami).

Another ancient genus of sharks that has extant species is the Heterodontus, which dates back to the Early Toarcian, meaning roughly 180 million years ago. The sharks in this genus are called bullhead sharks. All nine species in the genus are still alive! While there isn’t enough data about three species to understand how large their population is, the other six species are listed as “least Concern.”

Here are the species:

• Heterodontus francisci – horn sharks
• Heterodontus galeatus – crested bullhead sharks
• Heterodontus japonicus – Japanese bullhead sharks
• Heterodontus mexicanus – Mexican hornsharks
• Heterodontus omanensis – Oman bullhead sharks
• Heterodontus portusjacksoni – Port Jackson sharks
• Heterodontus quoyi – Galapagos bullhead sharks
• Heterodontus ramalheira – whitespotted bullhead sharks
• Heterodontus zebra – zebra bullhead sharks

Up Next:

• The 10 Craziest Prehistoric Sharks!
• 11 Types of Sharks that Went Extinct
• Why Scientists Were Stunned By An Unusual Shark Named The “Godzilla Shark”

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