The mysterious angelshark is thriving in Wales, new research by the Zoological Society of London (ZSL) has suggested , making it one of the last global "hotspots".
The rare creature comes from a family of sharks that is evolutionarily distinct, meaning that it represents its own branch of the evolutionary tree and has few or no close relatives in the animal kingdom.
Until recently, evidence for the sharks was haphazard and occasional sightings were reported on social media or to Natural Resources Wales.
But the first phase of the Angel Shark Project, part-funded by the Welsh government and run by the ZSL, the charity which also runs London Zoo, has seen 30 sightings reported in the last five years by fishermen trained to release the rare animal if they catch it by accident. It has been strictly protected in UK waters since 2008.
The numbers have prompted scientists to launch a cutting-edge DNA project to find out more about its life off the west coast.
Researchers are taking samples of water in Tremadog Bay, north Wales, every month for the next year to search for traces of the rare angelshark, which was once common throughout the north Atlantic but is now critically endangered.
Dr Joanna Barker, project lead, said the team was now trying to establish whether the rare sharks were living in the area all year round or just during the summer, when most sightings so far have been reported.
Scientists hope to identify areas where they are living in order to better protect them.
The Canary Islands is the last major stronghold for the animal, but Wales is one of a handful of other places where they are still thought to be living.
Three species of angelshark were once widespread in the north Atlantic but fishing and loss of habitat have left them under threat.
"When we’re talking about the north Atlantic, Wales really is quite unique because we haven’t seen records for many of the other countries that surround Northwest Europe.
"In the broader context, the Canary Islands is this huge hotspot and then a few separated pockets elsewhere in their range, of which Wales is one," she said.
The high-tech environmental DNA method involves filtering water samples and searching the residue for molecular traces of the sharks.
Typically used to search for invasive species, it is now increasingly being used to confirm the presence of endangered animals.
Angelsharks are thought to be particularly suited to the method because of their hunting practices, which involve burrowing into the sand to ambush unsuspecting prey.
This leaves behind traces from their mucus, skin, teeth and faeces.
Diver and Atlantic angelshark (Squatina squatina) with threatening gesture; the shark straightens up and shows teeth and dentition
The shark can be hard to spot in murky waters and is often mistaken for other species of fish or ray, so the team hopes this method will provide more evidence of their presence.
Dr Nisha Owen, director of conservation at charity On the EDGE Conservation, which part-funds the project, said: "Angelsharks are the second most threatened family of shark or ray in the entire world.
"Very little is known about them, because they’re so cryptic."
The UK has been a world leader in protection for angelsharks, banning any disturbance of them in 2008, a year ahead of the rest of the EU.
There is also a theory that Wales may be serving as a breeding ground for the sharks, because of a series of sightings of juveniles.
Records provided to the project date back to 1812 and include more than 2,000 sightings.