THIS spectacular marine creature — “one of the world’s rarest animals” — has been spotted by biologists for the first time in 31 years.

    The elusive mollusc was pictured in waters around Papua New Guinea after a painstaking four-year search.

    The nautilus called Allonautilus scrobiculatus is thought to have been around for more than 500 million years.

    Even since he first spotted it in 1984, University of Washington biologist Peter Ward has been looking to picture the animal.

    Ward and colleagues set up “bait on a stick” systems each evening — fish and chicken meat suspended on a pole between 500 feet (152 meters) and 1,300 feet below the surface — and filmed activity around the bait for 12 hours.

    “We started using this approach in 2011,” Ward told the University of Washington News.

    Then in July this year the biologists finally struck gold when one of the creatures appeared with another nautilus.

    Night footage from a site near the Ndrova Island showed the Allonautilus approach the bait — displaying unique features.

    Ward said: “It has this thick, hairy, slimy covering on its shell.

    “When we first saw that, we were astounded.”

    The team trapped several nautiluses, including Allonautilus — at a depth of about 600 feet.

    They got tissue, shell and mucous samples before releasing them.(SD-Agencies)