Parasite nicknamed 'monster in a barrel' and inspired Alien films found on Isles of Scilly

  • Footage captured showing the "monster in a barrel" parasite found off the Isles of Scilly

A parasite believed to have inspired the 'Alien' films has been found off the Isles of Scilly.

The phronima sedentaria — nicknamed "monster in a barrel" — was spotted on Porthcressa beach by Scott Reid on Monday 23 October.

The marine creatures, which are about an inch in size, were last recorded on the Isles of Scilly in 2018.

"There are not many documented records of them, as people tend to walk past them," Mr Reid said.

He added: "The barrel structure was no bigger than the end of my thumb, and the creature was slightly longer than a fingernail."

Mr Reid moved to the Isles of Scilly six years ago and leads wildlife rock pool tours on the island.

He studied ecology at university and has been trying to spot the creature for years.

The parasites are about an inch long Credit: Scott Reid

Mr Reid said: "I became aware of this amphipod crustacean a few years ago, and started looking out for them because I was just fascinated by their appearance."

He knew there was a chance of spotting one, he added, but couldn't believe it when he saw the clear barrel-like structure on the beach.

"I was incredibly happy and excited," he said. "After four years of looking for this species, it was a really special moment."

The marine creatures are a species of amphipod crustaceans, which are found in oceans at a depth of up to 1km.

They are parasitic creatures that prey on gelatinous plankton, such as salps.

Mr Reid explained: "They are really fast swimmers and they go in search of salps.

"They cut into the bottom of them, and eat the salp from the inside to construct a barrel-like vessel for themselves."

"She basically lives in there, and that's where she reproduces," he added.

In total, the creatures can raise up to 600 young inside the vessel.

Since posting his video online, Mr Reid said it has been shared all over the world.

He said: "They've got this stereotype of what we'd think of as an alien.

"But the creatures are absolutely harmless which is why I think they've captured people's imagination."

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