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Marine Biologists Identify Three New Nautilus Species

by Admin Staff
Marine Biologists Identify Three New Nautilus Species

The three new species of nautiluses belong to the genus Nautilus and represent populations on the easternmost edge of the overall habitat range of the genus.

Nautiluses are a charismatic group of marine mollusks best known for their rich fossil record.

But today they are restricted to a handful of species in two genera (Nautilus and Allonautilus) of the cephalopod family Nautilidae.

The three ‘universally’ accepted modern Nautilus species of 21st century taxonomists are Nautilus pompilius (type species), Nautilus macromphalus, and Nautilus stenomphalus.

Nautiluses first appeared 500 million years ago during the Cambrian explosion and are distant cousins of squid and cuttlefish.

These creatures are described as ‘living fossils’ because they have remained virtually unchanged for millions of years.

They occur in the tropical waters of Pacific and Indian oceans, near the coast of Japan, Fiji, New Caledonia and Australia.

Nautiluses have a shell diameter 10 and 25 cm across and more than 90 tentacles — the most of any cephalopod.

Unlike those of other cephalopods, their tentacles have grooves and ridges instead of suckers. These grooves and ridges are coated with a sticky secretion that help the animals grip food and pass it to their mouth. They use their sharp, beaklike mouth to break food apart, and their radula (a band of tissue lined with tiny teeth) to further shred their food.

Nautiluses swim using jet propulsion, expelling water from their mantle cavity through a siphon located near their head. By adjusting the direction of the siphon, they can swim forward, backward or sideways.

To avoid predators by day, nautiluses linger along deep reef slopes as deep as 700 m. At night, they migrate up to shallower depths of about 70 m to feed and lay their eggs.

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by Admin Staff


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