New species of sharks emerge from the depths

More and more new species of sharks are being discovered as humanity deepens into the oceans. Until the mid-eighties, science settled on about 360 species of sharks, but in less than 40 years, that number jumped by about 40%. There are more than 500 known species, and in 1989, scientists in Australia found a strange type of "mermaid purse" – a leather egg tray that some shark species put instead of being born alive. Empty egg trays had an almost unique feature - a row of ridges protruding along the top. In September 2024, a new species of ghost shark was identified thanks to the discovery of a specimen caught from the deep ocean off New Zealand's east coast. In 2011, a researcher named Brett Human found a pack of corrugated shark eggs. The animal has never been found in Australian waters. Human tied the egg tray to other eggs found off Australia, narrowing the species to being a member of the cat shark family.

A new wave of discoveries

Scientist White and his colleagues knew that the eggs recovered in the eighties came from a certain depth—between 410 meters (1,345 feet) and 504 meters (1,640 feet)—and began to search for sharks caught at the same depth. The Commonwealth Scientific and Industrial Research Organization group contained what was believed to be a South China cat shark, which turned out to be pregnant when it was caught. Scientists dissected it and found a developing embryo inside an egg tray in the same ridges that were discovered years ago.The investigation work proved that it is a completely new species, now the species has a scientific name and was revealed in the Journal of Fish Biology in April 2023. This new species of demonic shark, also known as Apristurus ovicorrugatus, is thought to dwell about 700 metres (2,297 ft) below the surface, laying its eggs above the coral in waters too deep for sunlight to penetrate. The demon shark wasn't the only discovery White had recently been involved in identifying. Another species, a species of shark, was caught in surprisingly deep waters off Western Australia in a survey last year. sharks tend to live in shallow water, but this new species is found at a depth of 150 metres (500 ft). The waters around Australia aren't the only ones introducing new species of sharks. On the other side of the Indian Ocean, German sharkologist Simon Wegman helped discover two new species of saw sharks – strange-looking creatures armed with a long snout, or beak, studded with sharp teeth – off the southeast coast of Africa. The saw sharks were found with the help of a colleague who was searching for new species of related sawfish off the coast of Madagascar. Wegman says one of her colleagues called her because fishermen kept two introductions for her, which they thought were sawfish. When she saw the pictures, she immediately realized that these were not chainsaw fish, but saw sharks, which is also an interesting discovery because saw sharks are not caught all day.

New types?

The saw sharks had some interesting details: instead of the five gill cracks that most sharks have, they had six – an evolutionary echo of the much older shark species that lived millions of years ago. It also had small fleshy cavities known as mustaches much closer to the tip of the front than in other species of saw sharks. Another shark researcher – Andrew Temple from KAUST in Saudi Arabia was contacted. They found a saw shark off Zanzibar in Tanzania, surveying the landing sites of local fishermen, which were even different from those found. "It's very special because saw sharks are not common and you only have a few species." But scientists like Weigmann weren't the first to notice something different, it was fishermen in Madagascar who caught them. "It was really important that we used local fishermen to supply us with these materials. If they hadn't collected the shark bones, or later brought the specimens taken in Zanzibar, we wouldn't have noticed. Many of the saw sharks discovered so far live at relatively distant depths in the ocean—at depths of up to 300 metres (1,000 ft)—but species off Zanzibar have been caught less than 30 metres (100 ft) from the surface. "We think they may have reached lower depths at night, which is normal for many marine populations," Weigmann says.

Future

There's much more in this discovery than just adding to the known genres in a reference book, or a new display at a museum. In 2021, scientists discovered three new deep-sea shark species that glow in the dark, including one that can grow up to 1.8 metres (5.9 ft). It's also been less than 50 years since researchers discovered a strange shark tangled in a naval anchor for a U.S. Navy ship off Hawaii. The shark in question was about 15 feet (4.5 m) tall and was a species never seen before – it feeds by filtration and swims with its jaws open. Sharkologist Leighton Taylor called it the "giant mouth shark"; this species is now considered one of the largest ever grown today. What might await shark scientists, far beneath the ocean's surface?