Living Fossils: Nautiluses

Living nautiluses are the survivors of a large group of shelled molluscs that first appeared in the seas long before the age of dinosaurs, perhaps as far back as 500 million years ago.  For this reason and the fact that they show many primitive features, they are today considered ‘living fossils’.

Nautilus pompilius. Images by Schmidt Ocean Institute.

Nautiluses are related to molluscs such as octopuses, squid and cuttlefish. Only five species exist: these occurring only in a narrow band of the world’s ocean including waters around tropical Australia, Melanesia, south east Asia and southern Japan. The nautilus usually lives at depths of around 100-400 metres and sometimes move to much shallower depths at night to continue their search for live or dead prey, usually crabs, lobsters or fish.

Painted Nautilus shell (edge damaged)-painted New Caledonian images, portraits of man and woman, village scenes, and crossed clubs. Image by Peter Waddington. 

The spiral shell which has internal chambers, has been used for souvenirs and collectables. The inner shell layer is often used as pearly inlay. Around the world, nautiluses are collected or fished commercially and are increasingly in need of protection.

Many believe that the shell is in the shape of the golden ratio, but alas it’s not true, although it is one of the finest natural of a logarithmic spiral. This beauty was photographed on the recent Schmidt Ocean Institute Research Voyage that Queensland Museum scientists were part of, and it’s alongside some examples of Nautilus shells from our collection.

Image by Peter Waddington.