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It's the kind of touching reunion biologists dream about: More than 30 years after finding and identifying a then-new species of nautilus off the coast of Papua New Guinea, Peter Ward finally got a chance to see it once more.

Allonautilus scrobiculatus is a species of nautilus, cousin to squids and cuttlefish. They skim the sea floor in warm waters and have a distinctive spiral shell — and in Allonautilus' case, that shell grows a strange furry, slimy material. Ward, a biologist at the University of Washington, told NBC News in an email that the covering may help prevent predators' teeth from getting a grip on the animal.

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This rare chance to observe Allonautilus came when Ward and a group of colleagues set up bait hundreds of feet below the surface and set a camera to keep watch day-round. Two species of the elusive nautilus appeared until a sunfish came along to bully them away from the food.

Ward and colleague Bruce Saunders of Bryn Mawr College identified Allonautilus in 1984, and Saunders made another brief sighting in 1986, but it hasn't been recorded since.

Allonautilus (bottom) and the more common Nautilus pompilius swim together off the coast of Ndrova Island in Papua New Guinea. Peter Ward

"It’s only near this tiny island," said Ward. "This could be the rarest animal in the world."

On the expedition in July, a few of the creatures were caught and temporarily brought to the surface for study — carefully, since nautiluses are very sensitive to heat differences.

The nautilus is also a living fossil. Animals extremely similar to today's nautiluses can be found as far as 500 million years back into the fossil record. That means they saw the dinosaurs come and go without missing a beat — but overfishing and disappearing niches may put an end to that long history.

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"As it stands now, nautilus mining could cause nautiluses to go extinct," Ward said. He isn't optimistic about upcoming talks to classify the nautilus as a protected animal, either. But nautiluses didn't survive two mass extinctions and half a billion years of sharp-toothed competition by being pushovers.