Super Rare Nautilus Observed After 31 Year Absence

Allonautilus scrobiculatus hasn't been seen since 1984.

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Nautilus pompilius (left) swimming next to a rare Allonautilus scrobiculatus (right) off of Ndrova Island in Papua New Guinea. Photo by Peter Ward
John Virata

An Allonautilus scrobiculatus, a nautilus considered by some to be one of the rarest animals in the world, was spotted after a 31 year absence by one of two researchers who had seen one decades ago. The nautilus was observed this summer by University of Washington biologist Peter Ward, who along with colleague Bruce Sanders first viewed the elusive creature back in 1984.

The nautilus was observed near Ndrova Island, Papua New Guinea, between 500 and 1,300 feet at a bait station the researchers set up. It was fighting with another nautilus for the food until a sunfish came upon the scene and kept them at bay. Ward used video cameras to capture the footage at that depth and even captured several specimens that were safely brought to the surface in chilled water where tissue, mucous and shell samples were taken before they were safely released back to the depths in which they were captured. This species is notable because it has a thick layer of slime and hair that covers its shell.

Nautiluses are called living fossils due to the fact that they have barely changed for more than 500 million years. This species has gills, jaws, and male reproductive structures that are different from other nautiluses. However, due in part to their body structure being relatively unchanged, their capability to adapt to change is limited. “Once they’re gone from an area, they’re gone for good,” Ward said in a statement released by the university. He noted that wherever nautiluses can be found, they swim just above the bottom, they can die if they go deeper than they are physically capable, and they don’t usually go to surface depths as the waters are too warm.

Nautiluses are so rarely seen that the U.S. Fish and Wildlife Service will determine in September 2015 whether to list them as a protected species under the Convention on International Trade in Endangered Species of Wildlife Fauna and Flora, or CITES treaty. If given protections, the trade in nautilus shells and harvesting would most likely be reduced.

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