Tarphycerids

Discussion in 'Cephalopod Fossils' started by Hajar, Dec 23, 2010.

  1. Hajar

    Hajar Haliphron Atlanticus Registered

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    Here's a pretty 9 cm Lituites from the Ordovician of Sweden. I've just been reading here that this was one of the first fossil cephalopods to be recognised.

    There's a tarphycerid from the Ordovician of the Welsh Borderland here.
     

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  2. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

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    Nice Fossil Hajar, I wish we had those here. Funny how nautiloids like these are not referrred to as heteromorphs. Aphetoceras with open coils and a ventral siphuncle, and Plectolites with a dorsal siphuncle, are examples of Tarphycerids also.
     
  3. Hajar

    Hajar Haliphron Atlanticus Registered

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    Just found a brand new publication by Turek & Manda discussing colour patterns in the tarphycerid Peismoceras. It can be downloaded from here (Turek & Manda 2010).

    They write "A marked asymmetry of colour pattern on lateral sides has been observed in several cases, but with no proven relationship to the slight dextral coiling of the shell."
     

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  4. Hajar

    Hajar Haliphron Atlanticus Registered

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    I thought I could see colour bands on this little 5 cm example of the common Chinese Lituites. Polishing the reverse side though I now see that the bands correspond to the positions of septa.
     

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  5. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

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    Do you think the septa are somehow the reason for the color bands?
     
  6. Hajar

    Hajar Haliphron Atlanticus Registered

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    Yes, in this case each of those red bands occurs at the edge of a septum. I don't think the red bands are actually at the surface of the shell (with its fine growth lines), but are visible through the calcite. Have you ever come across something like this?
     

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