'Unmissable' sea slug could be new species

A brightly-coloured sea slug spotted off an island's coast could potentially be a new species, according to marine experts.

The Marine Biological Association said the orange, purple and white nudibranch, also known as a sea slug, was spotted by Maggs Ashton while she was diving with Ilfracombe and North Devon Sub-Aqua Club off Lundy.

The creature, which was spotted in the wreckage of the MV Robert and measured 15mm (0.6 inches) in length, was found about 20 metres (65.6ft) under water.

Marine naturalist Bernard Picton said the find was "significant" and could be a species which had not been formally identified before.

Ashton said while the sea slug was small, her attention was drawn to its colourful appearance, while swimming around the boat which sank in 1975.

"I was just swimming along and not really looking that carefully when I suddenly saw it," she said.

"It just stood out and I'd never seen anything like it before in my 29 or 30 years or diving - it was really special."

Ashton said she sent her images off to marine biologists, who told her it appeared to be a species which had not been documented before.

"I've actually been back to the wreck to try and see it again, but I can't find it," Ashton added.

"Hopefully it is just hiding and hasn't been eaten by a fish."

Picton said he believed the animal to be an undescribed Lomanotus species, a genus of sea slug.

Being undescribed means it had never been identified, named or documented before, the Marine Biological Association added.

The association has appealed to divers, rockpoolers, sailors and fishers to record anything similar they spot and submit photographs to its data archive centre called DASSH.

A spokesperson said the recordings helped scientists to build a clearer picture of how coasts and seas were changing as waters warmed, including sightings of "unusual visitors and shifting species ranges".

"The discovery is another reminder that the marine life around Britain is ever-changing," the association said.

In 2025, young rockpoolers who joined the monthly Rock Pool Project Bioblitz, found a rare depilatory sea hare on Mount Batten beach in Plymouth.

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