The frilled shark—a roughly five-foot long fish with 300 teeth—was plucked by a trawler from more than 610 metres below the surface.
Speaking with Portuguese outlet SIC Noticisas TV, researchers said they were conducting a European Union project to minimise the bycatch, or unwanted catch, that results during commercial fishing, when they hauled up one of the world's rarest catches.
Frilled sharks are often called "living fossils," because in the 80 million years they've lived on Earth, the fish have changed little. The distant cousin of other sharks like great whites and hammerheads, frilled sharks have been swimming the Earth's depths since the time of dinosaurs.
The shark's 300 teeth may look intimidating, but they pose the biggest threat to the other fish and squid they're thought to feast on. Like modern-day sharks, frilled sharks have a hinged jaw that can catch large prey in the animal's needle-shaped teeth.
In a statement released by the Portuguese Institute for the Sea and Atmosphere, researchers aboard the ship described the shark as having a "long, slim body and a head that is reminiscent of a snake."
They also noted that little is known about the rarely seen species. It has been found throughout the Atlantic and in waters off the coasts of Japan and Australia. Because the shark lives at extreme depths, scientists are unsure of how many individuals comprise the population.
In 2007, an even rarer frilled shark sighting occurred when fishers saw the creature alive in Australia. Scientists believed it was only at the water's surface because it was sick or injured, and the fish died shortly after being transferred to a marine park.
While the International Union for the Conservation of Nature lists the frilled shark as a species of least concern, they noted that increasing deep water commercial fishing could increase the likelihood of the frilled shark becoming bycatch.
Lead Image: This frilled shark was pulled up from the waters off Australia this week, offering a rare look at a deep-sea creature. PHOTOGRAPH BY SETFIA. This image was originally posted in a National Geographic 2015 article 'Rare Shark That Inspired Sea Monster Myths Is Caught'.