© Monterey Bay Aquarium Research Institute
The mystery of a deep-sea creature that resembles a discarded purple sock has been solved, scientists report.
The animal, called
Xenoturbella, is so bizarre that for 60 years researchers could not work out what it was - or where it fitted into the family tree. But the discovery of four new species in the Pacific has enabled scientists to conclude that this animal belongs to one of the earliest branches of life.
The study is published
in the journal Nature. Lead researcher Prof Greg Rouse, from the Scripps Institution of Oceanography in the US, said: "Our nickname for them was purple socks. "So if you think of a sock that you have taken off and thrown on the floor - they literally look like that. "Or a deflated balloon."
Xenoturbella was first described in 1949. The ocean oddity has no eyes, no brain and no gut. Just a small gaping mouth from which food goes in - and then waste comes out. Only one species was known, and it left scientists scratching their heads.
Early genetic tests mistakenly placed the marine "sock" as a mollusc.
"But, it turned out they had sequenced the DNA of what it eats," explained Prof Rouse. Other researchers thought that it was a once-sophisticated creature that had got rid of all of its complex features as it evolved.
© Monterey Bay Aquarium Research Institute
With Remotely Operated Vehicles (ROVs), they have been able to
film these creatures for the first time. They include a new large specimen, which is more than 20cm-long, which has been called
Xenoturbella monstrosa. And also
Xenoturbella churro: named after the sweet, fried Spanish pastry, which it resembles - in an admittedly less appetising way.
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