The Bellybutton Nautilus (Nautilus macromphalus) is a species of nautilus, a marine cephalopod mollusc. It is distinguished by its distinctive spiral shell, which is characterized by a large, open umbilicus (the central opening in the shell), giving it its common name. The Bellybutton Nautilus is a fascinating and ancient creature, having existed for millions of years.
Description & Characteristics
The Bellybutton Nautilus, like other nautilus species, possesses a distinctive, coiled, external shell that provides protection and buoyancy. The shell is typically white or cream-colored with brown or reddish-brown markings. The umbilicus, or the central opening in the shell, is a defining characteristic of the species and is notably larger than in other nautilus species. This feature is responsible for its common name. The shell can reach a maximum diameter of around 20 cm. Nautilus macromphalus, like its relatives, has numerous tentacles surrounding its mouth, which are used for capturing prey and maneuvering.
Habitat and Occurrence
The Bellybutton Nautilus (Nautilus macromphalus) is found in the western Pacific Ocean, primarily in the waters surrounding Indonesia, the Philippines, and New Guinea. It is a deep-water species, typically inhabiting depths ranging from 100 to 600 meters. This depth range places it within the bathypelagic zone, often referred to as the “midnight zone,” characterized by perpetual darkness and low oxygen levels.
Taxonomy
The Bellybutton Nautilus (Nautilus macromphalus) is classified within the phylum Mollusca, specifically within the Class Cephalopoda, which encompasses squid, octopus, and cuttlefish. It belongs to the Order Nautilida, a group that includes all nautilus species. This order is further categorized within the Family Nautilidae, which encompasses all living nautilus species.
Feeding
The Bellybutton Nautilus (Nautilus macromphalus) is a carnivore, primarily feeding on a diet of crustaceans, such as krill, mysid shrimps, and zooplankton. It also occasionally consumes small fish. To capture prey, the nautilus extends its tentacles, which have sensitive receptors that allow it to detect prey in the dark depths of its habitat.
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