Bellybutton Nautilus
Encyclopedia
The Bellybutton Nautilus (Nautilus macromphalus) is a species of nautilus
native to the waters off New Caledonia
, the Loyalty Islands
, 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 approximately 15% of the shell diameter at its widest point.
Like all Nautilus species, N. macromphalus usually lives at depths of several hundred metres. During the night, however, they rise to much shallower waters (2 to 20 m depth) in order to feed.
The tentacle
s of this species are long and thin, having raised ridges which help provide grip when catching prey. N. macromphalus is the smallest species of nautilus. The shell is usually up to around 16 cm in diameter, although the largest specimen ever recorded measured 180 mm.
Nautilus
Nautilus is the common name of marine creatures of 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...
native to the waters off New Caledonia
New Caledonia
New Caledonia is a special collectivity of France located in the southwest Pacific Ocean, east of Australia and about from Metropolitan France. The archipelago, part of the Melanesia subregion, includes the main island of Grande Terre, the Loyalty Islands, the Belep archipelago, the Isle of...
, the Loyalty Islands
Loyalty Islands
The Loyalty Islands are an archipelago in the Pacific. They are part of the French territory of New Caledonia, whose mainland is away. They form the Loyalty Islands Province , one of the three provinces of New Caledonia...
, and northeastern Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. The shell of this species lacks a callus
Callus (disambiguation)
Callus means a hardening of a certain object or substance. It can refer to:*Callus, an area of toughened skin*Fibrocartilage callus, the temporary new bony tissue that forms at the ends of a fractured bone...
, leaving the umbilicus exposed, in which the inner coils of the shell are visible. This opening constitutes approximately 15% of the shell diameter at its widest point.
Like all Nautilus species, N. macromphalus usually lives at depths of several hundred metres. During the night, however, they rise to much shallower waters (2 to 20 m depth) in order to feed.
The tentacle
Tentacle
A tentacle or bothrium is one of usually two or more elongated flexible organs present in animals, especially invertebrates. The term may also refer to the hairs of the leaves of some insectivorous plants. Usually, tentacles are used for feeding, feeling and grasping. Anatomically, they work like...
s of this species are long and thin, having raised ridges which help provide grip when catching prey. N. macromphalus is the smallest species of nautilus. The shell is usually up to around 16 cm in diameter, although the largest specimen ever recorded measured 180 mm.