Nautilus! The start of something new, not the end of something old Brian McGowran

It was Charles Darwin who coined "living fossil" for those animals and plants, once diverse and widespread but not so in recent geological times, perhaps lurking only in a faraway place like Australia, and changing very little down the ages and through the epochs, seemingly going nowhere in their evolution whilst most of life was moving on.

For the naturalists of Europe the enigmatic and beautiful Nautilus pompilius was a classical living fossil. The swimming predatory molluscs known as Nautiloids flourished 500-400 million years ago but fell upon hard times in the age of the famous ammonites. A species here, a species there, they persisted while so many others went extinct, and their last representatives are to be found lurking only around the coral reefs of the southwest Pacific and northeast Indian Oceans.

Surely, a fine example of a lingering loser, a living fossil? Not so fast!

Eutrephoceras, the ancestor of Nautilus, indeed disappeared from our warm shallow seas such as the Murravian Gulf, covering the Murraylands and Riverland and extending almost to Broken Hill. But one species (in my opinion, Eutrephoceras altifrons) about two million years ago sought refuge from the predators of those shallow seas in the deeper waters off the coral reefs to our north.

And now the evolutionary geneticists are finding that populations of living Nautilus are speciating, sprouting new species. Nautilus includes a few living species with distinct shells, but there might be many more that are cryptic, not as yet looking distinctive. This is the start of an evolutionary radiation triggered by an ecological shift into a new habitat, and we can but hope that the radiation is not aborted by that most ruthless of predation, the unsustainable collecting for self-indulgent humans.

What an omen it is for the Nautilus Centre to perceive Nautilus not as the last of its kind after all, but as a promising evolutionary innovation, a risk-taking venture into a new habitat!