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The chambered nautilus (Nautilus pompilius), also called the pearly nautilus, is the best-known species of nautilus. The shell, when cut away, reveals a lining of lustrous nacre and displays a nearly perfect equiangular spiral, although it is not a golden spiral. The shell exhibits countershading, being light on the bottom and dark on top. This ...
Nautilus (from Latin nautilus 'paper nautilus', from Ancient Greek ναυτίλος nautílos 'little sailor') [3] are the ancient pelagic marine mollusc species of the cephalopod family Nautilidae. This is the sole extant family of the superfamily Nautilaceae and the suborder Nautilina .
Empty nautilus shells may drift a considerable distance and have been reported from Japan, India and Africa. Undoubtedly the same applies to the shells of fossil nautiloids, the gas inside the shell keeping it buoyant for some time after the animal's death, allowing the empty shell to be carried some distance from where the animal lived before ...
Nautilus have been noted to exhibit an extensive range of depth, close to 500 metres, however, they were demonstrated to be at risk of implosion when exceeding their depth and pressure limits. Depending on the species, the shells of live Nautilus will collapse at depths of 750 metres or deeper. [18] [4]
The Nautilaceae are represented by Nautilus and Allonautilus, genera included in the Nautilidae. Species in the Nautilaceae are generally smooth and involute with straight to strongly sinuous sutures and a small siphuncle. Some groups have sinuous plications or ribs.
When motionless, Nautilus can only extract 20% of oxygen from the water. [62] The jet velocity in Nautilus is much slower than in coleoids, but less musculature and energy is involved in its production. [75] Jet thrust in cephalopods is controlled primarily by the maximum diameter of the funnel orifice (or, perhaps, the average diameter of the ...
The Palau nautilus (Nautilus belauensis) is a nautiloid mainly found off of Palau in the Western Carolines. [2] It can be found on fore reef slopes, [3] at depths of 95m-504m (311'-1,653'), though typically preferring a range of 150m-300m (492'-984'), where water temperatures stay around 16.6 °C (61.88°F) and do not go much lower than 9.4 °C (48.92°F). [4]
Nautilus macromphalus, the bellybutton nautilus, is a species of nautilus native to the waters off New Caledonia and northeastern Australia. The shell of this species lacks a callus, leaving the umbilicus exposed, in which the inner coils of the shell are visible. This opening constitutes about 15% of the shell diameter at its widest point.