Deciding on my next sculpture

Discussion in 'Cephalopod Fossils' started by modelnut, Apr 3, 2014.

  1. modelnut

    modelnut O. vulgaris Registered

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    Deciding on my next sculpture. I just need to decide which style is best. Style A has a squid stuck in a conical shell. Style B has a nautilus stuck in a conical shell.
    Will the real
    giant orthocone please stand up!
     

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  2. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    It would seem that the body type of the squid would be less likely to have a tube (siphuncle) attachment and the large array of arms might be needed to haul the shell around. Since nautilus are the only remaining ceph attached to an outer shell and everything else has an internalized shell or no shell, I would use that weak logic to go with B. Pondering the body type, I wonder how long the arms would be in ratio to the cone. I lack any kind of swimming dynamics understanding but it would seem that a long straight cone would require long or very fat arms to maneuver. I wonder if the hood could have been used as a rudder of sorts.
     
  3. modelnut

    modelnut O. vulgaris Registered

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    We all saw type A in Nigel Marven's Sea Monsters.
    And that is the type I see online and in other documentaries.

    Type B makes a little more sense. But no soft parts have ever been found preserved.

    I may just sculpt both and to hell with it.

    - Leelan
     
  4. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    Where would the squid like animal put its arms for protection? Maybe it never withdrew them but the more you have me daydreaming, I think of short squat arms rather than long slim appendages.
     
  5. modelnut

    modelnut O. vulgaris Registered

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    Just found this to the right hand side of the Nigel Marven video:



    This is one of the only videos I have seen that have Cameroceras with a nautiloid body. It appears at the 15 minute mark.
     
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  6. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    Interesting tentacle idea but have we seen any evidence of a sheath like that? The creator must have been going down my, "how would it withdraw its arms" rabbit trail. This animal, however, would not likely be the super predator suggested in the first video. Following that idea, there is recent evidence that several of the larger sea creatures were more likely plankton feeders, detritus eater than carnivores.
    This is one I read about just last week.
     
  7. cuttlegirl

    cuttlegirl Colossal Squid Supporter Registered

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    What if the arms were more web-like, so they could capture plankton? Like vampyroteuthis maybe?
     
  8. modelnut

    modelnut O. vulgaris Registered

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    I saw this article (or one very like it a few weeks ago): http://www.wired.com/2012/04/ammonite-eats/

    I know very large animals like whales and sharks eat krill and plankton today. But they are lunge or cruise feeders. I don't see ammonites or orthocones building up enough steam to make that practical. Sure, orthocones with their jet engines were probably the fastest animals in the water at that time. But could an animal the size of a small couch with a telephone pole hanging off the back catch enough tiny morsels to make it worthwhile?
     
  9. modelnut

    modelnut O. vulgaris Registered

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    I don't see this fellow doing that when he was alive:

    [​IMG]
     
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  10. modelnut

    modelnut O. vulgaris Registered

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    I could build this:

    [​IMG]

    Rayonnoceras giganteum for National Geographic magazine

    But it isn't very sexy or dynamic.
     
  11. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    The guy above does look boring (and not very life like). I had to laugh though because I read your comment associated with the Rayonnoceras as being attached to the ammonite and was expecting an interesting scale model.

    I think I would agree (all from trying to think about dynamics I have no understanding of) the the curled shelled animals are likely to be meat eaters or at least scavengers but watching the humboldt video and thinking about that straight shell and the similar torpedo body design, I could imagine a similar feeding strategy but squid have "wings" to help swim and navigate, all this guy had was whatever poked out of the shell. I keep going back to where and how they retracted their arms and how powerful did the arms need to be to maneuver that shell. Surely the funnel was not their primary swimming engine as it would have had to be very large, very muscular and the internal capacity for water would need to take most of the shell, not leaving much room for the rest of the body parts. Maybe they didn't retract their arms at all and arms got shorter to become protectable?

    It would be so cool to see something like that fossil alive. I get it why @Architeuthoceras keeps hoping one will turn up.

    Edit: Another thought, maybe the body was not all that big so the quantity of food would be less important. A new nautilus keeper posted that his naut will eat once and only once a day, regardless of the size of the food offering.
     
    Last edited: Apr 4, 2014
  12. modelnut

    modelnut O. vulgaris Registered

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    [​IMG]
    This is the final sketch. The building has commenced.

    D,

    I've watched those video clips a few times now and I have some ideas.

    According to what paleontologists think they know, the shell aft of the body could be filled with air and water at the animal's desire via the siphuncle. Like a submarine this would determine the animal's depth in the water column. At whatever depth that was the entire beast would have neutral buoyancy. From the overall shape I would think that the center of gravity would be between the eyes and the stomach --- and balanced like a fine sword. So the orthocone would be very maneuverable and nimble. That's not to say that there wouldn't be considerable inertia to overcome. But surely the animal had evolved to be able to handle this otherwise they would not have achieved this incredible size.

    Given all of this I would think that Cameroceras moved like a modern squid or cuttlefish. Minus the fin of course. I'm sure the siphon or hyponome would have been very large and muscular. So I don't see why they wouldn't have moved very much like they were portrayed in these documentaries.

    - Leelan
     
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  13. modelnut

    modelnut O. vulgaris Registered

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    I've made two cones out of printer paper and covered with painters tape.

    [​IMG]

    And filled them with plaster. Once they are dry I will skin them with Apoxie Sculpt. I poured the plaster yesterday so they should be ready to skin today.

    [​IMG]

    Now I'm off to put the putty on them.

    - Leelan
     
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  14. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    It will be interesting to see what you come up with and how you "explain" the design (see what trouble you get yourself into by asking :sagrin:). I'm still hung up on envisioning how something that large moved. When I used to dive, I was neutrally buoyant with a full tank at 33 feet (one pressure depth) so I when I was in a known area, I would drop my 5 pound weight belt (always thought this was cool just because of the science). It still took a lot of arm and leg movement to swim, I just did not float to the top or sink. Granted, I may be considerably larger than the animal wielding the shell and am not cone shaped but I can't see those puny arms being useful for swimming and I don't see where there would be enough internal room to include enough water to jet for any sustained distance. So, to my way of thinking either the animal floated about and caught little stuff or it had very robust octopus like arms that could not retract (more like the film in post 3). Fun stuff to think about. It also gives me an a question to get @gjbarord to post an answering photo to on his FB nautilus page :grin:
     
  15. modelnut

    modelnut O. vulgaris Registered

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    If only some university professor would get together with a radio-controled submarine builder. They could test all of this out. Put three or four ballast tanks in the shell and a pulse jet in the back with a pivoting nozzle. They could get this figured out in no time. After all there was that professor who built himself a flying pteranodon and another who built a robot with four flippers to see how liopleurodon would swim. Surely a giant orthocone would be simpler than either of those.
     
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  16. modelnut

    modelnut O. vulgaris Registered

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    Skinned and sanded. One came out perfect --- the one I thought would be the most work to finish. The other has divots that need filling.

    [​IMG]
     
  17. modelnut

    modelnut O. vulgaris Registered

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    Can you tell the difference? The divots are filled now. I'm going to give the putty a good hour to cure before re-sanding.

    [​IMG]
     
  18. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    That is just plaster of paris that is sanded? What give it the purple and green colors? I assume the divots were air pockets.
     
  19. modelnut

    modelnut O. vulgaris Registered

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    This should explain things.

    [​IMG]

    The outer layer is Apoxie Sculpt, a two-part epoxy putty. The blue is the painter's tape. The white center is the plaster of Paris.

    The first step was to make the cones out of paper. I reinforced that with the painter's tape because paper just isn't water proof. I filled the cones with the water and plaster mixture and set it aside to dry for 24 hours. I needed a strong base to lay the putty on. Once the plaster hardened I sprayed primer on the cones because the putty needed the primer to be able to stick to the cones. The putty is grey. Sanding the putty lightens the color a bit so the divots stand out as a darker grey. The divots are there only because I didn't put enough putty in those places. It's hard to tell when the putty is wet. That's why the model builder's mantra is "putty-sand-and-repeat."

    The green highlights are just camera artifacts I think. The purple spots are the dark grey divots.
     
  20. modelnut

    modelnut O. vulgaris Registered

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    Here are the shells ready to receive their occupants. And here is a 35th scale diver to give them scale. You can see that one is a bit bigger than the other. (Oh well. I tried.) The upper shell will hold an animal much like the one that faced Nigel Marven. The lower one will have a more nautiloid face inside.

    [​IMG]

    The dark grey spots here just show where I filled in the divots with another contour putty. They don't show at all after I sprayed a primer coat on them. Now I need to make some arms after I have studied the two styles just a bit more. For that I need to get some screen captures from "Prehistoric Predators of the Past." I figure by Wednesday morning I can get the critters at least 80% sculpted. Maybe by this weekend or next Wednesday they will be ready to paint.

    - Leelan
     
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