In a chance discovery, a new species of deep-water hermit crab - the “green-eyed hermit crab” - has been discovered.
The creature is unique to South Africa’s West Coast.
UCT alumnus Lara Atkinson made the discovery while she was conducting a survey for the Department of Agriculture, Forestry and Fisheries three years ago, a UCT PhD candidate and researcher of this species, Jannes Lands-choff, said.
While Atkinson was investigating hake fish, she stumbled on the species.
Curious about the little crab, she sent it in for identification, and was surprised to find that she had discovered a new species.
It is unique for its “living shell” - soft, polypy masses that are amalgams of sand and material created by colonies of sea anemones that live on their backs.
Instead of a normal sea-like shell that most deep-water hermit crabs have, the green-eyed hermit crab has a pseudo-shell as it consists of the symbiotic relationship it has with anemones. Sea anemones anchor themselves on the backs of these hermit crabs for shelter and simultaneously grow as the crab grows.
In addition to their green eyes, other unique features include biserial gills and extreme sexual dimorphism. This means the male species grow a much larger right claw compared to females.
The crab measures around 70mm, and has been named after Atkinson, Paragiopa-gurus atkinsonae.
There is no indication why this species is restricted to this very small area of the West Coast, where Landschoff said there are between 2000 and 3000 of these crabs.
Landschoff and Rafael Lemaitre of the National Museum of Natural History at the Smithsonian Institution in the US described the new species in the journal ZooKeys.