30多年间生物学家首次发现鹦鹉螺

In early August, biologist Peter Ward returned from the South Pacific with news that he encountered an old friend, one he hadn't seen in over three decades. The University of Washington professor had seen what he considers one of the world's rarest animals, a remote encounter that may become even more infrequent if illegal fishing practices continue. The creature in question is Allonautilus scrobiculatus, a species of nautilus that Ward and a colleague had previously discovered off of Ndrova Island in Papua New Guinea. Nautiluses are small, distant cousins of squid and cuttlefish. They are an ancient lineage of animal, often christened a "living fossil" because their distinctive shells appear in the fossil record over an impressive 500 million year period. Ward says this recent sighting of Allonautilus indicates that there is still much to learn about these creatures. 

"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, when Ronald Reagan was finishing his first term as president and the oldest millennials were starting preschool. Ward and Saunders collected several Allonautilus scrobiculatus specimens for analysis and realized 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.