One of the world’s rarest – and oldest – catches has been pulled up from 600 metres below the surface of the sea.

The 1.5-metre-long frilled shark (Chlamydoselachus anguineus) was caught in a commercial trawler off Portugal’s Algarve Coast. The trawler was working to minimize undesirable catches in European fisheries, the Portuguese Institute for the Sea and the Atmosphere (IPMA) said in a statement on Monday.

Often referred to as "living fossils," frilled sharks have barely changed in biology over the 80 million years that the species has existed on Earth. 

Scientists at IPMA describe the fish as having “a long, slender body and a snake-like head,” and a “very particular dentition” that features 300 teeth.

IPMA researchers say the frilled shark lives all over the world – from the Norwegian coast through the waters of Scotland, down to the Azores and the Canary Islands and descending into the African Coast and Indian Ocean. From there, the species can also be found in the waters of Japan, Australia, and New Zealand.

But despite its almost global dispersion, scientists say that spotting a frilled shark is extremely rare due to how deep in the ocean they live.