A tiny, vividly coloured sea slug discovered off the British coastline may represent an entirely new species, according to marine experts.
The eye-catching nudibranch, with striking orange, purple and white markings, was found by diver Maggs Ashton while exploring a shipwreck near Lundy Island, Devon. At just 0.6 inches in length, the creature was located roughly 65ft beneath the surface, nestled within the remains of the MV Robert, which sank in 1975.
Marine naturalist Bernard Picton described the find as significant, suggesting the animal is probably a species that has never been formally recorded. Despite its small size, Maggs said the vibrant sea slug instantly caught her attention, as reported by What's The Jam.
She said: "I was just swimming along and not really looking that carefully when I suddenly saw it.
"It just stood out, and I'd never seen anything like it before in my 29 or 30 years of diving – it was really special."
After sending images of her discovery to marine biologists, Maggs was told it seemed to be a previously undocumented species. She has since made several trips back to the wreck hoping to spot it again, though without success so far.
She said: "I've actually been back to the wreck to try and see it again, but I can't find it.
"Hopefully it is just hiding and hasn't been eaten by a fish."
Picton suspects the creature may be an unrecorded species within Lomanotus, a genus of sea slug. He explained: "I think it is likely to be an undescribed Lomanotus species.
"In scientific terms, this is significant – an 'undescribed species' is one that has never been formally identified, named and documented in the scientific literature."
The organisation is now calling on divers, rockpoolers, sailors and fishers to stay alert for similar creatures and submit any photographs to DASSH, its data archive centre. A spokesperson said such records help researchers build a fuller picture of the changes taking place along Britain's coastline and in its waters as temperatures rise, including observations of "unusual visitors and shifting species ranges".
The body further noted: "The discovery is another reminder that the marine life around Britain is ever-changing."
This follows the finding of a scarce depilatory sea hare by young rockpoolers taking part in the monthly Rock Pool Project Bioblitz at Mount Batten beach in Plymouth during 2025.
Devon Diver Finds New Sea Slug Species Near Lundy Island