Nautilus, A living fossil

In the deep, cool waters of the Indo-Pacific, you will find a pre-historic relic which dates back to the late Triassic period. One of the last remaining Cephalopods with an externalised shell, the Nautilus is a slow moving, primitive creature that has remained largely unchanged for millions of years. The fossil record shows that the first Nautiloids were orthoconic (having straight shells) but rapidly evolved to form a planispiral (coiled) shell by the Devonian period, which is how they have remained. Both the Nautilus and their close cousin the Allonautilus are members of the Nautilidea family which has 6 extant species and several extinct species.

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