| Nautiloidea | |
|---|---|
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| Scientific classification |
Nautiluses are a large and diverse group of shelled cephalopods that appeared during the Cambrian, and have changed very little since. Because of this, they're seen as living fossils. Nautiluses resemble ammonites, but have several key differences. Nautiluses have pinhole eyes, whereas ammonites are presumed to have had camera lens eyes, much like other tentacled cephalopods (such as squid and octopi) and vertebrates.