Extinction: Why some and not others?

Discussion in 'Cephalopod Fossils' started by neurobadger, Jun 6, 2011.

  1. neurobadger

    neurobadger Vampyroteuthis Registered

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    Since I'm having a really hard time finding much information on this, what's the current idea on why ammonoids and belemnoids died while nautiloids and coleoids lived past the K-T boundary?
     
  2. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

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    My understanding is it has to do with 2 main things. 1, Reproduction strategy, Nautilus and some coleoids lay large eggs, ammonoids had small planktonic eggs and the hatchlings were plancktonic. 2, feeding habits, Nautilus is a scavenger, ammonoids ate planckton.

    These are generalized explanations, there are just as many theories on the extinction of ammonoids and belemnoids as there are for the extinction of non avian dinosaurs.

    I'll look for some references that may help.
     
  3. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

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    This Blog has an explanation and some references
     
  4. hallucigenia

    hallucigenia O. bimaculoides Supporter

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    It's also worth noting that the marine part of the K-T extinction is pretty diachronous, and doesn't line up particularly well with anoxic episodes in any of the shallow seas.

    Then again, Whiteside and Ward (2011 in Geology) claim to correlate the extinctions of the endoceratids and actinoceratids with intervals of chaotic carbon cycling, so there might be hope for the ocean-chemistry idea...
     

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