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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 .
[7] [8] In 1951, he determined that only extant species of Nautilus should be placed in the genus, despite many fossil species having already been assigned to it. [7] In the years following this conclusion, fossil species were still sometimes assigned to the genus; however, many other authors insisted that these be excluded. [4]
Furthermore, unlike the extinct ammonoids, the modern nautilus lacks an aptychus, a biomineralized plate which is proposed to act as an operculum which closes the shell to protect the body. However, aptychus-like plates are known from some extinct nautiloids, and they may be homologous to the fleshy hood of a modern nautilus. [3]
Miocene nautilids were still fairly widespread, but today the order includes only two genera, Nautilus and Allonautilus, limited to the southwest Pacific. The recent decrease in the once worldwide distribution of nautilids is now believed to have been caused by the spread of pinnipeds. [2]
As many whales begin to leave their protected zones in search of warmer waters, boats should take extra precautions. The post The Latest Whale Species Facing Extinction and What’s NOT Being Done ...
Because of their oceanic habitat, studies of their life cycle have primarily been based on captive animals and their eggs have never been seen in the wild. [7] Although nautilus have been kept at public aquariums since the 1950s, the chambered nautilus was first bred in captivity at the Waikiki Aquarium in 1995 (a couple of other nautilus species had been bred earlier) and captive breeding ...
On this day 57 years ago, Nautilus -- the world's first nuclear submarine -- accomplished its first undersea voyage to the North Pole. The submarine boasted huge proportions of 3,180 tons ...
Nautilus ' s keel was laid at General Dynamics' Electric Boat Division in Groton, Connecticut, by Harry S. Truman on 14 June 1952. [13] She was christened on 21 January 1954 and launched into the Thames River, sponsored by Mamie Eisenhower. Nautilus was commissioned on 30 September 1954, under the command of Commander Eugene P. Wilkinson, USN. [2]