Mollusca · mollusks

Chambered nautilus

Nautilus pompilius

Nautilidae · chambered nautilusesIUCN: Vulnerable
Chambered nautilus
Photo: Hans Hillewaert · CC BY-SA 4.0 · Wikimedia Commons · resized

A shelled cephalopod that controls its buoyancy by adjusting gas in its chambered shell.

Fun factIts lineage is more than 400 million years old, older than the dinosaurs.

Waters
Indo-Pacific
Depth zone
Coral reefs, Twilight zone, 200–1,000 m
Diet
Scavenger: crustaceans & carrion
Size
Shell up to 25 cm

Classification

Mollusca › Cephalopoda › Nautilidae

  1. Kingdom Animalia animals
    • Many-celled organisms that eat other living things for energy (heterotrophs)
    • Cells have no cell walls
    • Most can move at some stage of life
  2. Clade Bilateria bilateral animals
    • Body has a left and right side that mirror each other (bilateral symmetry)
    • Head end with concentrated nerves; three tissue layers
    • Includes about 99% of all living animal species
  3. Clade Protostomia protostomes
    • In the embryo, the first opening usually becomes the mouth
    • Main nerve cord runs along the belly (ventral)
    • Includes mollusks, worms, and arthropods
  4. Clade Spiralia mollusks, worms & kin
    • Embryos usually divide in a spiral pattern (spiral cleavage)
    • Many have a swimming larva with a band of cilia (trochophore)
    • Includes mollusks and segmented worms
  5. Phylum Mollusca mollusks
    • Soft body with a muscular foot and a fold of tissue (mantle) that makes the shell
    • Most have a rasping, tongue-like ribbon of teeth (radula)
    • Includes snails, clams, octopuses, and chitons
  6. Class Cephalopoda cephalopods
    • Foot is modified into arms and tentacles around the head
    • Large brains and camera-like eyes
    • Jet propulsion by squirting water through a funnel (siphon)
  7. Subclass Nautiloidea nautiluses
    • The only living cephalopods with an external shell
    • Shell has gas-filled chambers for buoyancy
    • Many (up to about 90) tentacles without suckers
  8. Family Nautilidae chambered nautiluses
    • Chambered nautiluses with a coiled, striped shell
    • Simple pinhole eyes without lenses
  9. Genus Nautilus
    • Species in the same genus are very close relatives and often look alike.
  10. Species Nautilus pompilius Chambered nautilus

Closest relatives in the guide