A team of scientists have discovered a new shark species, specifically the third kind of sixgill shark, in the Atlantic Ocean.
What differentiates the Atlantic sixgill shark from its cousins in the Indian Ocean and Pacific Ocean, and why are these sharks so special?
The Atlantic Sixgill Shark: A New Species
Through genetic testing, scientists confirmed the Atlantic sixgill shark is a new species that is different from the other kinds of sixgill shark found in the Indian Ocean and Pacific Ocean. The other two species in the family are the bluntnose sixgill shark and the bigeyed sixgill shark.
"We showed that the sixgills in the Atlantic are actually very different from the ones in the Indian and Pacific Oceans on a molecular level, to the point where it is obvious that they're a different species even though they look very similar to the naked eye," said Florida Institute of Technology assistant professor and shark biologist Toby Daly-Engel.
Scientists analyzed 1,310 base pairs of two mitochondrial genes to make the discovery, which was published in the Marine Biodiversity journal. They found that there were enough differences in the sixgill sharks in the Atlantic Ocean to consider them as a new species. The Atlantic sixgill shark is also called the Hexanchus vitulus.
The Atlantic sixgill shark has a length of up to 6 feet, smaller than their counterparts in the Indian Ocean and Pacific Ocean that can grow longer than 15 feet. In comparison, the average female Great white shark is 15 feet to 16 feet long. The lower teeth of the Atlantic sixgill shark resemble saws, and they have six gill slits, as suggested by their name, compared to five gill slits for most other shark species.
The importance of the discovery of the Atlantic sixgill shark is that it gives the species a better chance of survival in the long-term. Now that the third species has been identified, it is now known that overfishing sixgill sharks in the Atlantic Ocean should be prevented, as they are not the same ones found in the Indian Ocean and Pacific Ocean.
The Ancestors Of Sixgill Sharks
The sixgill sharks are one of the oldest residents of the Earth, with ancestors that date as far back as 250 million years. This means that sixgill sharks were already around even before the dinosaurs ruled the earth and survived through the catastrophe that wiped out the dinosaurs.
However, because sixgill sharks live thousands of feet below the surface of the ocean, they have proven to be challenging to study for scientists. The discovery of the Atlantic sixgill shark may lead to a better understanding of shark diversity, not just for the sixgill sharks but also for the entire species.