Nature Blog Network

Friday, October 9, 2009

Nautilus Night - Cephalopod of Diamonds

Ok. I said for each of the Ocean in the Classroom projects fully funded I would put up a post about one invert from the deck of cards I have been working on, along with a sneak peak at a card. So, since the Making Waves, Oceans and Landforms got fully funded, and in honor of Nautilus Night I bring you the Cephalopod of Diamonds - The Chambered Nautilus.

Classification for the Chambered Nautilus







N. belauensis

ResearchBlogging.orgSome interesting facts about the chambered nautilus (and other extant nautiloids):

The 6-7 (there is still debate on the status of one species) extant species of nautilus come from two genera, the 4-5 smooth nautilus'(genus Nautilus) and the 2 species of hairy nautilus (genus Allonautilus - literally "other nautilus").

They are the only remaining cephalopods that retain an external shell, which they use for defense and as a buoyancy control system. The shell, with buoyancy control, was a significant weapon evolutionarily, as it afforded the early cephalopods the protection of a thick shell yet the advanced buoyancy control unchained them from the sea floor as most of the periods marine arthropods were.

Modern nautilus are generally found on steep coral reef slopes at a depth of 200-400m during the day. They rise at night to feed near or at the surface, using the adjustable buoyancy of their gas filled shells to good effect during the vertical migration.

Unlike other cephalopods, the nautilus do not have a lensed eye. The nautilus eye is more like a pinhole camera, leading to the hypothesis that it uses olfaction to find it's prey (mostly shrimp and other crustaceans along with some small fish.)

Nautiloids also have upwards of 90 tentacles (compare with 8 arms of octopods and 8 arms an two tentacles of squid and cuttlefish.)

Last bit for this post is their lifespan and reproduction. Most cephalopods are short lived with overall lifespans of even the Giant Pacific Octopus being around 2-3 years. For most studied cephalopods natural death from old age occurs after mating, (and for females egg guarding), which is only done once (called semelparity). Nautilus can live in 15-20 years and mate year after year (iteroparity).

The nautilus are the ancient lineage of the cephalopods, descendants of and most like the orthocerids and other nautiloids that were a major predator of the seas in the Ordovician period. Modern nautiloids are the only cephalopods that retain their external shell and are often considered to be "living fossils" as they are very similar in appearance to the ammonites and nautiloids that emerged half a billion years ago in the Cambrian. However recent molecular studies are casting some doubt on the appropriateness of the "living fossil" moniker. Studies published in the past couple years have revealed that the 6-7 extant species of nautilus evolved much more recently, around 2 million years ago, in the seas around New Guinea. They then

Sinclair, B., Briskey, L., Aspden, W., & Pegg, G. (2006). Genetic diversity of isolated populations of Nautilus pompilius (Mollusca, Cephalopoda) in the Great Barrier Reef and Coral Sea Reviews in Fish Biology and Fisheries, 17 (2-3), 223-235 DOI: 10.1007/s11160-006-9030-x


  1. So, so nice! Will your cards be available for purchase once they're complete?

  2. Wow - love the card idea. A great hybrid between collector's cards and playing cards. Bravo!

  3. Thanks all!

    Yes, the cards will be available for purchase once completed. We are examining the legal issues since it involves a great deal of copyrights clearances and non-profit issues.

  4. These cards are amazing; I can't wait to buy a set for my lab! Also, I am giggling about the typo which makes it sound like nautilus use olfaction to hunt down and eat psychiatrists. (At least, I think it's a typo--unless shrink is a kind of small fish?)

  5. Thanks Dana, we'll be sure to let you know when they are available.

    The Nautilus has been known to lash out while in therapy (issues surrounding being hung with the whole living fossil label, quite the burden, especially since they are really relatively young.)

    Personally I sort of like the idea that Nautilus may act as a natural control against an overabundance of shrinks. Interesting....


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