Bear Gulch orthocones

Discussion in 'Cephalopod Fossils' started by Hajar, May 6, 2012.

  1. Hajar

    Hajar Haliphron Atlanticus Registered

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    Just some quick photos of a pair of Bear Gulch Carboniferous orthocones which show preservation of soft parts.
     

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  2. Hajar

    Hajar Haliphron Atlanticus Registered

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  3. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

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    Wonderful fossils Hajar!!

    It is amazing that the shell on these seems to have no distortion. You would think that to be compressed into a single plane like that they would show some kind of breakage. :shock:
     
  4. Terri

    Terri Sepia elegans Registered

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    Beautiful fossils!I don't think I've seen preservation like this in orthocones before. :cool: Is that link broken or is it just me?:heee:
     
  5. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

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    Forbidden
     
  6. Terri

    Terri Sepia elegans Registered

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    OMINOUS:sagrin:
     
  7. Terri

    Terri Sepia elegans Registered

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  8. Hajar

    Hajar Haliphron Atlanticus Registered

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    Exactly right Terri! Thanks for that, not sure what happened there.
     
  9. Jean

    Jean Colossal Squid Supporter

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    What wonderful Fossils!
     
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  10. Terri

    Terri Sepia elegans Registered

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    Your welcome! Really interesting paper.
     
  11. Solius

    Solius Blue Ring Registered

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    A very informative discussion of epizoans in the paper. I have never seen cornulitids on cephalopods.
     
  12. Hajar

    Hajar Haliphron Atlanticus Registered

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    Thanks Jean. I like this paper too Terri and Solius. I've still not seen Mehl's paper on the Silurian Michelinoceras with arms.

    I wonder if perhaps early dissolution of the shell could be an explanation for the lack of obvious crushing and breaking Kevin

    Here attached is a closeup of part of the group of orange objects in the smooth-shelled orthocone (95 mm long), field of view about 2.5 mm so they're tiny. The arrowhead-shaped one looks a bit like a rhachidean tooth and there are several more elongate structures reaching about half a mm long in that area. I'm not sure. It would be great to find an articulated radula in these rocks.
     

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  13. Terri

    Terri Sepia elegans Registered

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    Great! I was hoping for a closer view.:cool:
     
  14. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

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    Have any of these from Bear Gulch ever been CT'd, UV'd, or Xrayed? Do you think it would help?
     
  15. Hajar

    Hajar Haliphron Atlanticus Registered

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    Great thought Kevin. I just found my old UV lamp again and the only thing that lights up (apart from a few scattered dust particles) are the robust-looking phosphatic structures in both of these orthocones. Tempting to think of these as beaks, but in the strongly ribbed individual there's a carbonized structure in front of that which is similar to what I think has been interpreted as mandibles in the coiled nautiloids of Bear Gulch. CT and Xradiography could show something, but contrast in these specimens will be less than in the cases of pyritized fossils in mud rocks.
     
  16. Hajar

    Hajar Haliphron Atlanticus Registered

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    I got hold of the Mehl Silurian Michelinoceras paper and here are some pictures of radulae from the paper.
     

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  17. Hajar

    Hajar Haliphron Atlanticus Registered

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    Just one more picture from the Mehl paper - the supposed pair of tentacles. I wonder if these could be trace fossils since there seem to be some other horizontal burrows on this bedding plane.
     

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  18. Terri

    Terri Sepia elegans Registered

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    Cool! I had a feeling you would come up with that paper. :smile: I really wanted to see the pics. of the as you put it "supposed tentacles". I'm definitely not an expert on these things but (without seeing a closer view) I agree they do "appear" to be conveniently placed burrows. Still intriguing....one of my dreams to find some sort of tentacle trace.
     
  19. Hajar

    Hajar Haliphron Atlanticus Registered

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    A little disappointing isn't it? I've seen the paper referenced as saying that there are ten arm impressions, but actually it says that two large tentacle impressions are in evidence and that an eight-armed plus two-tentacled ("10 Fangarme") beast is plausible. Keep looking !
     
  20. Hajar

    Hajar Haliphron Atlanticus Registered

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    .. and I'll keep looking too!
     

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