Rare nautilus sighted for first time in 30 years

Biologist Peter Ward has recorded a sighting in the South Pacific of an Allonautilus scrobiculatus, a species of nautilus considered one of the world’s rarest animals.

Ward and a colleague previously discovered the species of nautilus off of Ndrova Island in Papua New Guinea.

Nautiluses are small, distant cousins of squid and cuttlefish with an accent lineage, so ancient they are often called “living fossils”. Their distinctive shells appear in the fossil record over a 500 million year period.

Ward says this recent sighting of Allonautilus indicates that there is still much to learn about these creatures. The University of Washington professor hasn’t seen one in 30 years. He says that they are threatened by illegal fishing.

“Before this, two humans had seen Allonautilus scrobiculatus,” said Ward, who holds appointments at the UW in both the Department of Biology and the Department of Earth and Space Sciences.

“My colleague Bruce Saunders from Bryn Mawr College found Allonautilus first, and I saw them a few weeks later.”

Those sightings were in 1984. Ward and Saunders collected several Allonautilus scrobiculatus specimens for analysis and realised that their gills, jaws, shell shape and male reproductive structures differ significantly from other nautilus species.

“Some features of the nautilus – like the shell giving it the ‘living fossil’ label – may not have changed for a long time, but other parts have,” said Ward.

Nautilus 2
Nautilus pompilius (left) swimming next to a rare Allonautilus scrobiculatus (right) off of Ndrova Island in Papua New Guinea.
Credit: Peter Ward

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