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Cephalopod siphuncle questions


minnbuckeye

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Locally, I find quite a few large cephalopods. Here is an example: IMG_20180811_103842528_HDR.thumb.jpg.6e63a7da80c1ff934193606e523a4646.jpg

 

 Unfortunately this specimen was deteriorated. and I collected only it's exposed siphuncle. 

After gluing it back together, I noticed definite narrowings that I do not understand. Other siphuncles I have found have raised areas on them, not narrowings. Any ideas on this anatomical aspect???

 

DSC_0832.thumb.JPG.3e557a8a9b2134b9e14ac38d0569479b.JPG 

DSC_0833.thumb.JPG.f69c3fefa7c3fd30423dd7dd1f2d56be.JPG 

 

 Here is another cephalopod I found that day. Love the crystals inside.

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Congrats on a great find. Can't help with your question but will follow for hopefully more info. What is the average distance between the narrowings? And what was the size overall (length) and the width (diameter) of this awesome critter? Amazing that they could move around which leads me to ask the diameter of the siphuncle? I'm very curious since I have never found or even seen a large orthocone. Estimates would suffice to give me an idea. Thanks for posting.

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@fossilnut, I do not know the length of this cephalopod as I quit exposing it due to it's deteriorated condition. What is exposed would be about 3.5 feet as an estimate, maybe 4.  The length of the siphuncle in the picture is 13 ", 5" between narrowings, and just under 1" in diameter. If you can use it in your cephalopod lectures, I can send it to you. Still have your address. 

 

Mike

 

@Raggedy Man, have to get the fossils out before you or Bev find them. LOL

 

 

 To the rest of the Fossil Forum, no ideas??

 

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@minnbuckeyeThanks for that info. The awesomeness of the creature continues to impress. Shows how neural buoyancy can offset the size and weight. What a large siphuncle! At least in my limited experience. Sorry no responses yet re the narrowing. If I come across anything will let you know. I think that is an impressive treasure. Congrats on the find.

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@minnbuckeyeNo written info but here is a screenshot after searching siphuncle. Notice the narrowing just after its passing thru the septa. Would the thickness of the chambers correspond to the length of the sphuncle section between the narrowings?

Screenshot_2018-10-01 siphuncle fossils - AOL Image Search Results.png

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Narrowings on the siphuncle can vary from species to species, some nautiloids have straight siphuncles others have narrowings.

I know that specialists in nautiloids cut the cones throuh the siphuncle in the lenght to identify them on genus and species level, but I dont know al the details on this.

 

growing old is mandatory but growing up is optional.

 

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Wow, what a find!:envy:

"Absence of evidence is not evidence of absence"_ Carl Sagen

No trees were killed in this posting......however, many innocent electrons were diverted from where they originally intended to go.

" I think, therefore I collect fossils." _ Me

"When you have eliminated the impossible, whatever remains, however improbable, must be the truth."__S. Holmes

"can't we all just get along?" Jack Nicholson from Mars Attacks

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The narrow parts would be where the connecting rings from the septa joined the siphuncle.  However I am at a loss to suggest an ID for your critter.  Five inches between septa would have been a huge animal!  Are there any other details to be seen on the larger part, such as suture lines or any ornament?

 

Don

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@fossilnut, great image. I see the narrowing very vividly. But this picture shows the narrowing cranial (in front of) to the septal ring. This brings up the question of why?? Do a few more hours research for me, will you?? LOL Thanks for the info provided. I am serious about my offer IF it fits into your presentation on cephalopods. Just message me.

 

 @Manticocerasman, thanks for the education.
 

@fossilDAWG, we have large cephalopods locally. One was found 10 miles from here that was longer than a large couch! Unfortunately, the main body of this specimen just broke apart as I tried to salvage it. Even before I began to try and extract it, the cephalopod showed major deterioration to the body.

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As said before the septal rings/necks caused this narrowings. Here one can find basic infos about septal necks and septal rings. Fig. 7, 8, 9,

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