Newly Discovered 10-Foot Shark Was Hiding in Plain Sight for Decades

A closer look at the shark's anatomy and DNA revealed it wasn't what it was thought to be.

For years, researchers thought they knew all there was to know about this mysterious deep-sea predator. A closer look at its anatomy and DNA revealed an entirely different story.

Fishermen working the deep waters of the Indian Ocean occasionally hauled up an unusual shark. This new specimen was collected at Sakthikulangara Fishing Harbour in Kerala, where deep-sea shrimp trawlers had unintentionally caught them in their nets.

Growing nearly 10 feet long (three meters), with dark skin covered in thorn-like scales, the creature was hardly inconspicuous. Scientists believed they knew exactly what it was. As it turns out, they were wrong.

Indian researchers now report that the shark, long identified as the Atlantic bramble shark, is actually an entirely different species. Coined Echinorhinus roinee, or the Indian bramble shark, the animal had been hiding in plain sight for years, mistaken for a distant relative living thousands of miles away.

If scientists could overlook a shark nearly the length of a small Honda, what else might be lurking in the ocean’s depths?

A case of mistaken identity

Bramble sharks are peculiar animals. Unlike the sleek, torpedo-shaped sharks, these deepwater creatures have thick bodies covered with rough, thorn-like structures. These modified scales are made from materials similar to those found in teeth. As the sharks mature, some of the denticles merge into larger, multi-pointed plates.

The newly identified Indian species inhabits the continental slope, where the seafloor drops away from the relatively shallow waters surrounding a continent. It lives at depths of approximately 1,150 to 1,480 feet (350 to 450 meters).

Studying animals at these depths is difficult, and scientists frequently rely on specimens brought ashore by commercial fishing vessels. In this case, those specimens would eventually reveal that an apparently familiar shark was something else entirely.

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Scientists from the Zoological Survey of India and the ICAR-Central Marine Fisheries Research Institute began examining the sharks more closely. They discovered subtle differences distinguishing the Indian specimens from their Atlantic relatives.

However, the decisive evidence came from DNA.

After analysis, the results showed the Indian sharks belonged to a distinct genetic lineage, separate from both the Atlantic bramble shark and the Pacific prickly shark (Echinorhinus cookei).

“For decades, the bramble shark in our deep waters was assumed to be the same species found in the Atlantic,” said Dhriti Banerjee, director of the Zoological Survey of India.

A discovery with bigger implications

Recognizing the Indian bramble shark as a separate species does more than add another name to the scientific record. It could also change how researchers understand shark populations throughout the Indian Ocean.

Previously, fisheries records and ecological surveys had classified these animals as Atlantic bramble sharks. That means information about where the sharks live, how frequently they are caught and potentially how their populations are changing may have been grouped under the wrong species. Scientists cannot reliably assess the conservation needs of an animal unless they know which species they are studying.

Accidental catches by fishermen, known as bycatch, can provide scientists with valuable specimens, but they also raise questions about the effects of fishing on poorly understood marine populations. Genetic records suggest the species may inhabit a much larger portion of the Indian Ocean, potentially extending into waters near Oman, Sri Lanka and Thailand.

All this raises another question: How many sharks previously identified as Atlantic bramble sharks elsewhere in the region might actually belong to this newly recognized species?

Answering it will require additional specimens, genetic comparisons and more detailed surveys of these deep-sea ecosystems.

Much of the deep sea is inaccessible without specialized vessels, remotely operated vehicles or sophisticated sampling equipment. Even when animals are collected, distinguishing closely related species can be surprisingly difficult.

This is why modern genetic techniques are so valuable. They are helping researchers revisit older classifications and identify biological differences that traditional examinations sometimes miss.

The Indian bramble shark is a great example. This wasn’t a tiny creature hidden beneath a rock or a microscopic organism requiring a powerful instrument to see. It was a large predator that had appeared in fishing catches for years.

The researchers have deposited reference specimens in the National Zoological Collections in Chennai, allowing future scientists to examine the animals and compare them with other bramble sharks.

The new species is now part of the scientific record, but much about its biology remains unknown, including its reproductive habits, population trends and ecological role.

Finding something new doesn’t always require venturing into unexplored territory. Sometimes it means taking a second look at something we thought we already understood.

The new shark was described in the Records of the Zoological Survey of India.