'Lliving fossils' nautilus and allonautilus shaped by depths and diets over 500 million years

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Peter Ward, UW professor of both biology and Earth and space sciences, has spent his career studying the "living fossils" of Nautilus and Allonautilus species. Shown here is Ward holding Nautilus pompilius (white) and Allonautilus scrobiculatus (yellow) while scuba diving off the coast of Manus Island in 2015. Credit: Peter Ward/University of Washington

Nautilus and Allonautilus cephalopods and their extinct ancestors have been drifting through the mesophotic zone of the ocean for more than 500 million years. Researchers have spent the last 40 years trying to understand how these mysterious "living fossils" thrive in areas with limited nutrients.

In a recent paper published in Scientific Reports, a UW-led team documented new habits and habitats for current Nautilus and Allonautilus species. These creatures appear to live in deeper water than their extinct cousins did, and the younger ones live twice as deep as the fully mature adults. Nautilus and Allonautilus species scavenge their food and never stop moving.

While a few species migrate hundreds of meters down at dawn and then back up at dusk every day, the team found that most species aren't quite as intrepid. The researchers also describe a new population of Allonautilus in waters off the island of New Britain, one of several populations thriving due to hunting restrictions inspired in part by research efforts from this team.

Publication details

Peter D. Ward et al, Comparative habits and habitat in extant and extinct nautiloid cephalopods from acoustic telemetry and stable oxygen isotope analyses, Scientific Reports (2026). DOI: 10.1038/s41598-026-36623-x

Journal information: Scientific Reports

Key concepts

migratory speciesinvertebrate paleontologymigration (organisms)mollusks

Provided by University of Washington