The shark is said to date back 80 million years and features a range of primitive features, such as 300 sharp teeth and a weakened vertebrae among other attributes.
European Union scientists working off the coast of Portugal caught the toothy beast in a trawler net while carrying out research to "minimise unwanted catches in commercial fishing".
After noticing the creature's unusual appearance, the commercial fishermen handed it over to a research team from the Institute for the Sea and Atmospheres, who were working on a project to decrease unwanted catches in commercial fishing. It also has a rather unique teeth arrangement, but there's little else known about the shark's biology or ecology.
The captured shark was found to be a male specimen that measured five feet in length, with a slim and long snake-like body.
An even harder-to-spot cousin of Chlamydoselachus anguineus is Megachasma pelagios - or the megamouth shark - of which there have only been 63 confirmed sightings.
Its typical habitat is deep underwater in the Atlantic and off the coasts of Australia, New Zealand and Japan.
Frilled sharks are members of some of the most ancient groups of sharks that are known for having extra gills, big mouths, eyes on the side of their heads and spineless back fins.
This isn't the first time that a frilled shark has been caught, a year ago a fisherman called Roman Fedortsov had posted pictures of a frilled shark he caught in Russian Federation.
The frilled shark has rarely been encountered alive, and thus poses no danger to humans, although scientists have accidentally cut themselves examining the species teeth.