Eutrephoceratidae

Nautilus Temporal range: Triassic–Present PreЄ Є O S D C P T J K Pg N
Nautilus belauensis
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	Nautiloidea
Order:	Nautilida
Superfamily:	Nautilaceae
Family:	Nautilidae Blainville, 1825
Genera
†Carinonautilus †Cenoceras †Eutrephoceras †Pseudocenoceras †Strionautilus Allonautilus Nautilus † = Extinct
Synonyms
Eutrephoceratidae Miller, 1951

†Carinonautilus
†Cenoceras
†Eutrephoceras
†Pseudocenoceras
†Strionautilus
Allonautilus
Nautilus
† = Extinct

The nautilus (from the Latin form of the original Ancient Greek: ναυτίλος, 'sailor') is a pelagic marine mollusc of the cephalopod family Nautilidae, the sole extant family of the superfamily Nautilaceae and of its smaller but near equal suborder, Nautilina.

It comprises six living species in two genera, the type of which is the genus Nautilus. Though it more specifically refers to species Nautilus pompilius, the name chambered nautilus is also used for any of the Nautilidae. All are protected under CITES Appendix II.

Nautilidae, both extant and extinct, are characterized by involute or more or less convolute shells that are generally smooth, with compressed or depressed whorl sections, straight to sinuous sutures, and a tubular, generally central siphuncle. Having survived relatively unchanged for millions of years, nautiluses represent the only living members of the subclass nautiloidea, and are often considered "living fossils".