According to a press release by the Alliance of Mediterranean News Agencies, scientists from the country’s Institute For The Sea and Atmosphere have dubbed the shark a “living fossil”, as remains of the shark date back around 80 million years.
The discovery of the shark – a male 1.5 metres in length (5ft) and caught at a depth of 700 metres (2,300ft) off the resort of Portimao - was considered a rare find.
The shark itself is little known in terms of it's biology or environment and is rarely caught.
The frilled shark's snake-like movements and elongated, eel-like body is said to have inspired sailors' stories of sea serpents, after Samuel Garman first studied the shark in 1884.
Professor Margarida Castro of the University of the Algarve told Sic Noticias that the shark gets its name from its frilled arrangement of 300 teeth, which allows the shark "to trap squid, fish and other sharks in sudden lunges."
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.