Nautilus. The nautilus 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 hundreds of millions of years, nautiluses represent the only living members of the subclass nautiloidea, and are often considered living fossils.
The word nautilus is derived from the Greek nautílos and originally referred to the paper nautiluses of the genus Argonauta, which are actually octopuses. The word nautílos literally means sailor, as paper nautiluses were thought to use two of their arms as sails.
The tentacles of the nautiluses are actually cirri, composed of long, soft, flexible appendages which are retractable into corresponding hardened sheaths. Unlike the 8-10 head appendages of coleoid cephalopods, nautiluses have many cirri. In the early
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 hundreds of millions of years, nautiluses represent the only living members of the subclass nautiloidea, and are often considered living fossils.
The word nautilus is derived from the Greek nautílos and originally referred to the paper nautiluses of the genus Argonauta, which are actually octopuses. The word nautílos literally means sailor, as paper nautiluses were thought to use two of their arms as sails.
The tentacles of the nautiluses are actually cirri, composed of long, soft, flexible appendages which are retractable into corresponding hardened sheaths. Unlike the 8-10 head appendages of coleoid cephalopods, nautiluses have many cirri. In the early
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