Bellybutton Nautilus

Bellybutton Nautilus
Bellybutton Nautilus
Nautilus macromphalus
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Order: Nautilida
Family: Nautilidae
Genus: Nautilus
Species: N. macromphalus
Binomial name
Nautilus macromphalus
Sowerby, 1848

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 tentacles 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.[1]

  • N. macromphalus seen during a night dive in Sandal Wood Bay, Lifou, New Caledonia at a depth of 15 m

  • Pair of N. macromphalus in Sandal Wood Bay

  • Nautilus macromphalus shell

  • Anatomy of N. macromphalus from Arthur Willey's monograph, 1912

  • Map of Gazelle Peninsula, where Arthur Willey attempted to catch N. macromphalus

References

  1. ^ Pisor, D. L. (2005). Registry of World Record Size Shells (4th edition ed.). Snail's Pace Productions and ConchBooks. p. 93. 
  • Norman, M. 2000. Cephalopods: A World Guide. Hackenheim, ConchBooks, p. 30.

External links

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