The fossilized remains of Cthulhu have been discovered in England – but it's probably safe to look upon its form without going mad. Palaeontologists have described a new species of extinct sea cucumber that resembles a mess of tentacles, earning it the scientific name of Sollasina cthulhu, in honor of H.P. Lovecraft's mythical sea entity.

Dated back some 430 million years, the fossilized creature has 45 tentacles, branching out from a central body covered in rigid plates. Its discoverers say that those those tentacles likely helped Sollasina crawl around the sea floor, as well as passing food to the mouth in the center of the body. While it looks pretty intimidating, the whole creature only measures a measly 3 cm (1.2 in) wide.

To get a better understanding of the insides of the animal, the researchers recreated it in 3D as a "virtual fossil." First they ground it away layer by layer, taking a photo at each stage. The images of each "slice" can then be put back together digitally, creating a 3D model of the fossil.

Doing this, the researchers discovered an internal ring that appears to have been part of a water vascular system, which animals like sea cucumbers use to move and feed. The surprising part, though, was that this system wasn't known about in this kind of creature.

"Sollasina belongs to an extinct group called the ophiocistioids, and this new material provides the first information on the group's internal structures," says Imran Rahman, lead author of the study. "This includes an inner ring-like form that has never been described in the group before. We interpret this as the first evidence of the soft parts of the water vascular system in ophiocistioids."

While Sollasina looks like a kind of sea urchin, the team's analyses of the evolutionary history of similar creatures found that it's more closely related to the sea cucumber.

"We carried out a number of analyses to work out whether Sollasina was more closely related to sea cucumbers or sea urchins," says Jeffrey Thompson, co-author of the study. "To our surprise, the results suggest it was an ancient sea cucumber. This helps us understand the changes that occurred during the early evolution of the group, which ultimately gave rise to the slug-like forms we see today."

The research was published in the journal Proceedings of the Royal Society B.

View gallery - 2 images